Peugeotech's 505 V8 build (Rover 4.6L)

[Bean]

Interesting point that the 504's prefer less castor with wide tires - I thought the rule of thumb was as much castor as you can as it increases stability especially on loose surfaces as well as the self centering of the steering wheel more. I'll definitely keep it in mind with the huge jump to the 17" wheels on the 505. Do you have any recommendations for suspension tuning to reduce the negative effects increasing the scrub radius when fitting wider tires and rims?

Rear cross member: I have a few spares, so I really want to try welding the ends up solid, along with some cross member reinforcement like the Safari cars had. If I bodge it up I can replace it, but I think it's worth a try. A good friend is a suspension engineer and he advised trying to lower the cross member so that the trailing arms were horizontal - he said it should reduce suspension hop on hard acceleration and allow it to put the power down better - so I'll be welding the cross member to the bottom of the boxes as an experiment - but all depends on how much lower I can bring the suspension down and still retain good wheel and tire clearances.

504: I'll try to hold out for some proper 83 wagon LCA's as the car is just a really fun street car. It was a blast on the race track for my road racing school - but my 505 Turbo with all the trick bits will be my tarmac car - the 504 is just going to be my summer DD / fun car.

Rabin

[Stewart]

As Cookie Monster say's, OK, Ok , Ok, Me get thinking, Rabin!

A change in scrub radius, circumference of tyre and the tyre profile needs to be nutted out. The whole aim of steering geometry mathematics is to get as close to full, tyre contact patch engagement, with the road. That patch is quite small so, if using a low profile tyre, it's sidewall flexes less than a larger side wall. Tyre load rating and traction rating, will give us an idea about it's flexibility.

Remember " Slip Angle"? Stiffer tread band and side wall band means less "slip angle". That gives us less flexibility. Less Toe , less Camber for turn in and Castor can be reduced. Castor is the Vertically Angular difference , with our 505's, through the centre of the top of the strut, through the centre of the ball joint to the ground and a line 90 deg through the top of strut to ground.

Engineers in Peugeot,Citroen and Renault have mastered this. A bit of thinkin' and measurin' should get us close.

[Bean]

Biggest problem with going with wider tires is the clearance to the strut tube. I am very familiar with the meanings of the suspension settings, but what I lack is the experience in tuning them with relation to the effect on the handling of the car which is why your feedback is awesome!

I have 17x8.5" rims to fit onto the 505, and they'll essentially have the same wheel backspacing as the stock wheels (4.5") in order to clear the strut tubes, but the width being 8.5" means the center of the contact patch is being moved 2.5" outside the designed center of the contact patch therefore increasing the scrub radius 2.5"... Tires will likely be Continental DW's - but I may go all out and fit R compound tires, and the DW's to the stock style 138 BMW wheels. I fitted 235-45-17's on these 7.5" rims to flush the design and clearances out with, and if all goes well - I'd like a set of 255-40-17's on the 8.5" Racing Dynamic RGP rims on the car. I'll admit looks being a big driver, but with the brake and power mods the car should rival some pretty serious sports cars.

The only way around this scrub radius increase is to change the suspension design, so not really an option at this point - so the only other options I have are to tweak the alignment specs to hopefully counteract the tendency to tramline or climb out of road grooves making the car quite darty. This characteristics I'm expecting - not certain about any other ill handling symptoms to expect. I can live with a little, and I really have no idea how the car will handle with the changes I'm making - so it'll be a total learning experience once I get it all fitted and can start playing around with the set up. Biggest worry is that I'll bodge up the sweet driving feel and have to take even further steps to get it back!

If all goes well - I'd like a set of 255-40-17's on the 8.5" rims on the car. I'll admit mostly for looks, but with the brake and power mods the car should rival some pretty serious sports cars.

Rabin

[Stewart]

Mate, I'm so glad I didn't offend! I get a bit serious about it all sometimes! What happens if you use the 2 piece strut and knuckle?

This thinking has made me remember my the 505 V6 beast my brother Andy, built. He ran 7" on the front in 15". with a very low profile Mich. The inner rim was a good 1' off the strut, too. He ran manual steer with a 604 pinion turned down to suit. It pushed a little sometimes but only if you forgot how fast you were going and how wet it was. I reckon your idea will end up a little better because of the larger diameter brings the scrub in more than what Andy had and you have power steer. Andy liked to keep fit and wasn't scared of heavier steering any way. He looks like a retired Rambo now!

I have the engine from the V6, as luck has it. The heads were worked over and cams designed by guy called Ian Woodwood. He did an engeering trade apprenticeship with a bloke called Ron Richards. A lot of water gone under the bridge but I can say the torque was fantastic. We used the Renault 30 exhaust manifolds swapped left to right, I still have them too.

Back to the front end, we ran close to 0 camber with those rims. My thinking is 1/4 neg to 0 and as low Castor we might get from a urethane front bush pushing the arm back. I think we could get close to 8 or 10mm thickness behind the castor mount and start with 1 mm toe total?

I've nearly got myself organised to unpack and set up the lathe I bought for my 50th so if you like I could knock up a couple of test bits to try for castor.

I have this old 505 to set bits up on and a wheel alignment machine so if you have any ideas regarding the steering I can probably test them here. It helps me too!

Nice to compare notes. Thanks.

.

[andrethx]

noob question -- i understand that, when one goes to wider wheels with the 505, you can't change the backspacing (since there's no more room against the struts) so wider wheels means a different offset, which means a change in the scrub radius. here's my question -- is it possible to change the top mounting point of the front strut (moving it inboard, i guess) to preserve the original scrub radius, or does that do horrible things to the camber? would you have to move the lower pivot points on the front suspension (custom-fabricated arms?)?

andré

[Bean]

noob question -- i understand that, when one goes to wider wheels with the 505, you can't change the backspacing (since there's no more room against the struts) so wider wheels means a different offset, which means a change in the scrub radius. here's my question -- is it possible to change the top mounting point of the front strut (moving it inboard, i guess) to preserve the original scrub radius, or does that do horrible things to the camber? would you have to move the lower pivot points on the front suspension (custom-fabricated arms?)?

andré

Great question Andre - and it's a bit complicated since the early 505's use a 1pc strut/spindle assembly, and my 89' uses a 2pc strut/spindle assembly much like your Jetta. So the best way I can describe what is happening is to imagine the whole strut assembly turning from side to side. The strut itself pivots on two points - the top strut mount, and the ball joint. If you draw a line through those two points and continue it down to the pavement, that line should be dead center of the tires contact patch. So if you were to turn your tires side to side and then drive off - the tire contact patch marks should show the contact patch rotated about it's center.

When you increase the scrub radius - that center of the contact patch moves to the outside of the patch, and instead of rotating about the center the contact patch moves in an arc - and that arc is the scrub radius.

So on the 1pc strut the only way to move that point when fitting wider tires would be to change the angle of the strut tube in relation to the spindle by cutting and re-welding, but then you would either have to extend the LCA or move the top mount in so that your wheel camber was OK. (so yes it would bugger the camber if you just moved the strut mount inward or extended the LCA without strut modification)

On the 2pc strut it's the same principle, but instead of cutting and welding you would have to play with the strut to spindle mounting holes, and do the same LCA extension or move the top mount in. It all comes down to that rotating motion of the strut assembly so that the tire rotates about the very centre of the tire's contact patch.

My project already spiraled out of control, so I thought I'd assemble it as is, and then try to tune out some of the negative effects though alignment tweaks. I have done a little bit to minimize the scrub radius: Since my wheels are 2" larger in diameter, I was able to move the wheels a little closer to the strut tube to reduce the increased scrub radius by almost 1/4". and since the wheels are a little larger in diameter the point that intersects the contact patch moves a little closer to the middle.

I really don't know what to expect to be honest, but I have to admit my instinct was the exact opposite of Stewart's suggestion and I was going to try more Castor. 0 degree alignment feels really nice - so I's start there and see how the car handles. With Stewart's suggestion - I'll now play with castor as well to see how I can try to offset some of the side effects of scrub radius.

Stewart - No offense taken at all, I just wanted to save you some time on the discussion, but it's still great info since others are going to be reading this and the more clarity the better. Your offer to make and test fit is absolutely amazing - but my 89' has the newer suspension that pretty much uses an entirely new suspension design - including the bushings in the front that would determine castor, and a one piece LCA. What I may do however is draw up the dimensions of the bushing and see if you'd be able to make something up depending on how I'm able to make out with my alignment tuning. I'll likely just use shims to get an idea of what feels good, and once I've finalized a set up look at a proper set of bushings done to spec.

Rabin

[Stewart]

Love to.

I did some quick sypherin' ( Jethro Bodine style) and some remembering back to the 80's and as I said, I reckon it'll be pretty sweet with 0 to -0.15 deg. Camber and about 8 to 10mm backwards from the front castor mount. (old 505). And, with a larger diameter the scrub radius starts to head back in.

I recall Andy used the std front bushes which really flattened out quickly. They stayed pretty flat about 8mm thick on the front side of the bush.

Quite absorbing this chat, Rabin! Good fun. It'll be interesting for everyone to establish just what is going to work! Especially with the late gear you have.

I looked over a 208 today, which has 17" Pug optional rims. They were 225 or something. I must admit I'm looking at this sort of sizing myself. Pick up some 2nd hand late rims. We have trouble here getting 16" Michelin tyres. Every thing wide seems to be 17". I can get 15" street legal Yoko. motorsport rubber though.

[Bean]

Sweet Beverly Hillbillies reference Stewart! I didn't know that show as popular down there.

Tires selection is very similar here, and 17's are pretty much the smallest size that still has excellent tire selection. The 505 is a fairly small sedan, and 17" rims are pretty much my own personal maximum size wise not only asthetically - but also because our roads are so bad that running low aspect ratio tires means your rims take a beating.

I LOVE discussing technical aspects like this, and gaining new perspectives and new knowledge! So thanks very much indeed. I just need the weather to smarten up so I can make some quick progress on my garage so that I can work on my Peugeot. We had even more snow fall this morning and it's April 15th - it's by far the latest winter in recent memory by far.

I'm really under the gun to get some results quick on my car as I REALLY want to drive it to Pike's Peak for the June 30th race - It's a must see with Peugeot returning to the hill with the 208 T16!

Rabin

[Stewart]

I think it was Ellie May did it for me. Her and Catwoman. Hot dawg! I still think of Jethro eatin' Grannies vittles licking the pencil to do some sums and a sypherin' Uncle Jed. Funny boy. That lunatic who plays Oswald on Drew Carey channels Jethro, I reckon. Not enough clever people in humor, these days.

By the way, what bore, boost and compression are you anticipating using in the engine? I've developed a tidy set of Algebra that has been undergoing testing in my 2.2 as a method of writing a safe drivable curve that gets close first go. It's for 13 to 1 loaded and 14 to 1 cruise mixture and has proven itself once I got the ratios right. It would be interesting to see how my thinkin' and tinkerin' shows against your VEMS.

I've been working on it in my spare time, for the past 2 long years. Worked out of the box on a 347 SBF and a 351 Cleveland I built for street use.

In NA Carb engines it is actually very accurate against the higher output factory engine's curves. I did the 2l. Ti engine in my fathers 404 ute and even he had to admit it was smoother and added torque. Added another 10% economy saving without touching the mixture. Might be worth a go to reduce the tune time?

[Bean]

OK - now I'm just flat out giddy writing this as my engine plan is mostly based on educated guessing, and sheer displacement.

Plan so far is to use 94mm air cooled VW forged pistons with custom rods on an offset ground crank. Idea was to hopefully find a suitable existing connecting rod that's easily available, the have the pistons custom machined to make it all work.

Compression I was thinking of 8.5:1 or even 9:1 if the combustion chamber looks to be detonation resistant enough. It's the Danielson head with 10mm spark plugs and a redone chamber design that doesn't have the stock spark plug recess.

Boost I'd like a max of 18 - 20 psi, but it all depends on how the engine turns out and what my numbers are. If I can make 300 RWHP on less boost - great.

I'd be very happy to hear your thoughts on that tentative plan, and happy to flush out a better design based on your experiences and your findings.

Ditto on Ellie May too...

Rabin

[Stewart]

I'm running 9.2 at 18, no worries with proper accurate ignition. I see how you thinking 300 atw with the engine. 94mm bore, yes Sir! Funny with the 94 VW stuff. We are running a set in a 4.6 Rover. Plenty of meat to work with and trim. Very heavy gudgeons so that needs addressing. Easy.

I have a program here at home, of one of my suppliers, Precision International that might be of use. Piston pin heights, crown dimensions etc. I can tell you though that, an extra point in compression makes a big difference in off idle torque, ( actually 1 point in CR is considered close to 10% increase) but one must be carefull as the starter motor's are not really up for it. I made a reduction gear one up , that stopped it farting in Church! More capacity and a DCR between 7.0 and 8.5 to 1 at crank speed, is in the back of my thoughts. That would be about 8.5 to 10 static, depending on cam from, my rough calcs.

Bare with me everyone!

I noticed something today on that great build Tama has done. A fine and fast machine.

There is an image of broken rings and damaged piston between top and second rings.

( Apart from dusty air wearing ring lands and causing ring flutter which breaks ring lands), there are two usual causes for that damage between the two top rings. Predominately it gets down to ring material ( not bedding in, giving blowby and crappy oil control) and wide ring gaps.

Plenty more in that but, the oil explodes during the fuel burn process and the poor pistons rings and lands get smashed with an uncontrolled blast many times over . Have a look at the piston. Why did the piston break, between the two top compression rings?

[Bean]

Is 9.2:1 the static compression you're running?

Yup - The VW pistons seem to be the universal slug for engine modifications. I found threads on them being used in Saab and Volvo engines which is why I started looking at them. Plan was to contact one of the companies that supply forged VW pistons AND how have the N9TE patterns - then request the N9TE piston dish on the VW piston with the the pin height needed as determined by the connecting rod.

For the connecting rods I was looking at the Mitsubishi 4G63 or even the Ford 2.3 Turbo connecting rods as a starting point, and then figure out what my pin height needs to be in the custom piston. If you're program can let you run options and determine the numbers and such based on the changes made that would be ideal. If I had the time I'm sure I could build a spread sheet that could do the math automatically - but time is the tough part these days.

I should be able to provide you with the Danielson cam specs (I think) as I believe August got the specs for having stock cams reground to Dani specs. The more educated my engine build the better!

DCR: I needed to educate myself on Dynamic Compression Ratio and found this: http://www.wallaceracing.com/dynamic-cr.php That then led me to all sorts of calculators: http://www.wallaceracing.com/Calculators.htm I had heard the term many times, but never given much thought to it. After some quick reading I'm very glad you brought it up! Seems like an excellent tool to help flush out details on a totally new engine build. Once I'm in a position to do some hard number crunching I'll have to work with you Steward to find out what should be the best engine combo to go with. I'm totally fine basing my desicions on calcuations - but having your experience to sort though and suggest a direction is more valuable than any online calculator can be.

As for the piston failure you mention - my guess would have been ring end gap too tight, or too much clearance in the ring groove itself that allowed the ring to move

Rabin

[Stewart]

Yep! 9.2 static. After blowing a few and also running 12 :1 with an SC12 supercharger at 5 psi. ( Which was very torquey but nowhere near the sting I wanted) I decided that easy drivability in heavy traffic was smarter. The set up I had with 12:1 and the cam was getting hard to live with as I could'nt keep the speed limit of 60 kph if the blower was on. Crazy hey? 3rd or 4th at 60 kph, the little 404 was " nup! I'm goin' man, git me outer here!". The turbo is much faster but civilised. Typing this I recall I wanted to go more static with the new set up with my new design cam but I't is easier for me to dial in 2 deg advance on cam timing. The old engines actually failed from poor ignition control, detonation and preignition but not from high compression. It was engine oil exploding before or during combustion. I speak the bitter truth as I learnt ( read that, relearned and remembered early trade teachings) and studied a few engineering sites and publications. Poor oil control from engine breather and rings will confuse the engine tuner and at times the engine will be tuned to run allowing for detonation caused by hot oil. The anomaly is, when cold there is less oil entering and it is not at a temp high enough to be very volatile. Different matter once it gets over 90 C. though. A big issue with rings and broken pistons is material and hone pattern depth before bed in.

Chrome faced rings will not bed in unless the compression is very high. No good for us they will let oil past them almost straight away. Cast iron rings or Moly faced iron rings, gapped correctly is a great start.

Ring gaps make or break the fun of it all. From SAE Int. the standards for ring gaps is very interesting. The 2nd ring gap needs to be a lot less than the top. If the piston breaks as in Tamo's machine , it begins to indicate high pressure build up between the two rings. That makes them vibrate and flutter, then crack goes the land, before or after a ring breaks as well. Indipendant of boost or compression numbers.

So what I've learned, and am trying to share without sounding arrogant, is engine oil and breather control is the number 1 issue before building any engine. . Stop any oil vapour before it gets to the inlet, make sure that vapour returns as liquid oil back to the sump and control that oil with accurate and correct ring selection, gaps and hone. ( Rotary engines inject oil in for lubrication. Engine blows them up, specifically designed oils like Silkolene, Motul don't explode in that enviroment.)

The engine rings bed in quickly using run in oil in about 20 hours, this way. Bitter experience!

I do have Dani. cams data somewhere but Lordy Lordy, Uncle Jed. Ifferrin' y'all kin git me the figures of bore stroke and cam timings we can work something out here, without me checkin' under Ellie May's.........................................................................................................................

..chair!

[Bean]

Arrogance is the least of your worries Stewart - I'm finding this discussion absolutely fanatastic, and I'm learning a ton which is always my goal. I'll try to get the engine info posted in the next few days for sure as I'm very curious to see what kind of N9TEA build plan results from some very educated bench racing!

In the meantime - This is my solution for controlling engine oil vapour in the PCV system: https://www.mann-hummel.com/fileadmin/user_upload/service/catalogues/pdf/MH_ProVent_en.pdf

I've already purchased the Provent 200 as it's supposed to be very good oil /air separation system.

Rabin

[andrethx]

very interesting! i looked up the provent 200, to see what it costs...one of the first sites i found was an audi tuning webstore that has it for US$185; they also have lots of cool bits there, including electrical connections for FI harnesses which is a possible future project for me.

two questions:

1) the filter media on the provent is re-usable, correct? that is to say, it can be cleaned and re-used, it doesn't need to be replaced?

2) where will you route the clean oil from the provent?

andré

[Stewart]

That is the business, Rabin.

I'm going to "vent" me old crank case now, so here she goes!

The idea is to vent the OHC at the top of the engine and with a T piece from the crank case as well. It will make the gas work out some of it's energy on the way to the vent/filter which is mounted above the engine. ( Gravity is useful here.) Consider the P 200 as a condenser for oil vapour. Any gas, which should only be air , oil vapour and a tiny amount of blow by, must push it's way through the filter medium to get out. Energy is released, oil falls into the base and gets plumbed back to ideally the sump, below oil level. Then the outlet can go to the air filter. One can use a PCV, say from a Rover which screws into the manifold. Plumb it to a T piece in the hose going to the air filter. A small vacuum source is also important as it helps evacuate the crank case when the engine is cold. Moisture in the air can become ice cream in the oil from no other reason than it not being vented well enough. A vac source does this and keeps the oil clean, too. Many racers use a belt driven or electric vac pump to pull a vac. under the rings so they seal better. I've found using a PCV valve also helps the idle quality, too. The French use a metered orifice in most engines but a quality PCV, ( Positive Crankcase Ventilation) valve is much better.

Strange things float around in a mechanic's head.

[Stewart]

Rabin,

Here is some info from Total seal rings regarding their gapless style. It is one example of their requirements on ring gap.

Something to think about.

Top ring Bore x 0.0045"

Second Bore x 0.0035"

http://www.totalseal.com/TechPage.aspx#trRingInstall.

Over the years ring gaps have increased in spec for rebuild engine parts and I suspect the reason for that is ring maker reputation. Here's why. A lot of engines get overheated after the install. Thermostat stuck, radiator not cleand, broken old heater hose, loose hose clamp. Then if the rings expand enough they can butt together and break. Immediately it's someones fault. Usually the guy who rebuilt or the "crap" ring syndrome. Seen it many times, unfortunately! In standard applications Mahle use at least 0.005" sometimes 0.006.

Just stuff rattling around in the head I wanted to share with like minded fellows.

[Bean]

Thanks for that description Stewart! I've been thinking of using the Subaru PCV valve myself - tapping it into the intake as the source of vacuum. Difference was that I wanted to verify what the can was catching before connecting the drain from the Provent to the turbo oil drain that goes back into the pan.

Did some digging online for engine specs - I'll confirm them from the FSM later if that's OK.

Cam specs here: http://www.505turbo.com/forum/index.php?/topic/14-politecnic-danielson-camshaft-specifications/

Stock bore and stroke: Bore 91.7 mm (3.61 in) and stroke 81.6 mm (3.21 in)

My current plan was to run the 94mm pistons, with offset ground crank to gain another 2-3mm in stroke. This would keep the bore to stroke ratio roughly the same, while at the same time realize huge weight reductions in the pistons, rods, and the crank modifications (Stock bits are very heavy). Offset crank will be very pricey however, so failing that, I may decide on leaving the crank as is with custom pistons and rods. Regardless - the whole rotating assemble would be balanced as well.

Static compression ratio of 8.5 - 9.0 was the goal. I was going to specify the stock piston deck height at TDC, with the factory dish ~1.5 to 2mm deep (I'll do final calcs once I cc the dani combustion chambers)

Now that you've educated me on dynamic compression ratio calculations - the engine design is wide open for bench racing the best options based on a reasonable budget of course.

FYI: George Nunez detailed the Dani head differences here:

http://www.geocities.ws/MotorCity/Track/4889/505dani.htm

I'm hoping you can tell me what you think of the combustion chamber design and any thoughts on how resistant they might be for pushing static compression up a bit more to maybe even as high as 9.5 : 1... I still will likely play it safe with a max of 9:1 - but totally open to discussion!

Rabin

[Stewart]

Can you believe I've typed an extensive reply twice and have just bloody moved pages and lost me words! And now the missuss wants to talk!!!!!!!!!

Jim Miller reminds we practical men about our high school Geometry. Some Cam Grinders, most Cam Makers agree with him.

http://www.mid-lift.com/MID-LIFT-TECH.htm

Where"s that vino?

[Bean]

Awesome link Stewart - I've bookmarked it for purchase / download when I have the time to really dive into it.

Hopefully reading it will allow me to figure out exactly what those Dani cam specs mean! I already have the Dani cam - but I've often wondered if the stock cam might be better suited for the power curve I'm after.

Rabin

[Stewart]

Rabin,

That head looks damn fine! Independent of all we've potificated about, we need to check the famous "Squish" shapes and clearances first. Then you'll have a very clear vision of the future. It might be as easy as getting the engine mocked up and measuring deck height to crown. Measure the head gasket fire ring diameter on a used gasket and measure it's crushed thickness.

1/ Piston crown height at TDC relative to deck .

2/Used gasket thickness and bore dimension.

a/ or the biggest diameter quality gasket data available to us.

3/ Head your going to use cc's.

4/ Both valve head diameters from that head

a/ If the valves are different to standard, can I have those diameters too, please? I suspect that Dani increased exhaust valve size, from the images. ( Very rudimentary theory is to have an exhaust opening area 7/8 of inlet area.Valve diameter or lift can change to suit 7/8 area In.)

5/ This might lead us to a sweet compromise with a move like bore/pistons in oversize to suit gasket dimension. Deck the block , for a squish depth of the head gasket, which are usually 0.037" to 0.040" . ( Splendid number for this) Or offset grind, which is simple. The hard part is to match bearings and rods again. Maybe Tamo's data can help here? Over size bore is sooo much easier if it fits in with gasket dimension.. Stroking is the ideal way, in todays technology but not easy. An identical rod with smaller big end is the starting place.

6/ Then we can calculate a static CR figure. Then valve timing for our DCR. Sure we may need to increase the piston bowl, but from the few numbers we have so far, probably not.

7/ Cylinder Mean Effective Pressure is more dependent on CR rather than boost. This is where we get the wind from to spin the turbo early. VNT and you boooggie!

8/ I love this s###!

The Dani spec cam on a std engine would have to have been a high rev very laggy cam, even if it had the correct springs and geometry.. 6.42 DCR .at 9 :1! 6:1 at 8.5. Hopeless....It needed 12 :1 to get close to what we want..

Once we sort the static CR we sort cam timing and especially lift. Springs are no problem as my colleague here down under makes them and retainers for me for what I want. If you want to read up with Jim Miller he'll explain why we can dial in quite low seat pressures relative to popular practice.

Burton Engineering establish 25% of Inlet valve head is the max lift needed. Not much more usefull wind will blow past, no matter how far it opens further. That said, opening aforememntioned inlet valve further than 25% does get it further open, earlier!!!!!!!!!!!!!!!!!!

I'm off to run naked now. It seems to be a common folly for lunatics and I don't want to miss out!

[Bean]

Wow... You sir are a Jedi engine master. I am just a Padawan requesting your teachings! (I like Star Wars - but had to google for the lingo!)

Couple things real quick before I start collecting the data you requested.

• Cometic gaskets in the US has the N9TE pattern and I can specify whatever thickness or whatever bore diameter no problem. They can't justify the cost of doing MLS gaskets - but I found a source in Asia that will make an MLS gasket to spec if needed for decent money. Tama and VM also used a very cool HG out of Itali I believe that's very nice - but pricey - so there are lots of options if needed. Since I'm not going for ridiculous power - I thought a good quality Cometic gasket was all that was needed.
• Valves should be the same as stock. The stock heads have been flow tested, and stock out of the box they will support a lot of horsepower - so I was just going to do some minor porting and polishing with some focus on the inside radius to the intake valves - some improvements to flow there for sure.
• Squish areas: That figure 8 shaped chamber is reflected into the piston dish, so all around that chamber is the squish / quench pads. I should be able to cc a stock head which should have a few more cc than the Dani head.
• You pretty much NAILED the power description of the stock N9TE engines that have had the Dani cam and head installed on stock bottom ends. Laggy power, but once into revs it would accelerate well past the 6K redline.. (third party descriptions from memory) I was thinking I could offset the laggyness with a super fast spooling turbo, but if there's no wind as you say - then my idea would have proven wrong.
• Goal for me was super responsive throttle, with good offboost power, and giggle factory when the turbo spooled. Was hoping to have turbo spooled as low as possible - but tuning for max power under the curve with very quick response.
• I love this shit too!

I'm beyond excited about the possiblity of actually designing a proper performance N9TE build from the ground up. I've hoped that I would would have been able to gather this kind of info as I went, but working under a mentor with your experience ramps up this learning curve into an exponential curve. I'm a smart guy - but being able to discuss ideas and have feed back and explanations is outstanding.

Going forward the only real engine components I am married too are the block, crank and the Dani head. I can have stock cams reground to spec if the Dani cam isn't suitable, and pistons and connecting rods can be custom made for very reasonable money if I can find suitable cross over items that can then be custom machined. Not having to offset grind the crank would be nice - but not a deal breaker if it becomes key to the build. I'm also totally open to leaving bore and just increasing stroke - which ever works best.

Cost is a concern of course - but with a design flushed out it makes it much easier to justify the cash since there shouldn't be much guess work or trial an error if we do our homework properly.

Rabin

[Stewart]

I'm flattered mate!

I reckon get a used VNT turbo or a T25 equivalent modern design. I think using the std exhaust manifold to start with and encasing it in a heat shield will be an easy start. We will have to inspect the layout of it and consider it after we get the engine numbers sorted.

I can say that the more capacity we can use with best DCR to suit, will shove hot gas into a hot manifold to exit at speed through the right exducer and engine pipe. I'm glad I can share. Helps me too.

I just had a thought flash across the blurred grey cells. If you cc the head and we go for a gasket 0.035" thick. Then you tell me if each valve can be opened 0.040" to 0.050" or so and if they are below or level with with the head face, we might just find a flat top piston, like the VW will fall into our lap, compression target wise. A cam of 224 deg at 0.050" is the maximum being used for high torque turbo, these days. It means the inlet is open at TDC but only 0.040" or so. We will consider that as a max duration to start and perhaps trim it once we gather cam sheet data and I find all of mine! I'll start looking for what I gathered before I made up my cam for the turbo 2.2.

Over and out Obi Wan.

[Bean]

Simple extrapolation and the flat top piston would put static compression ~10:1... If there was any valve clearance issues the pistons could be flycut with reliefs to keep as much compression as possible, but my concern of course would be detonation under boost. If the combustion chamber design looks to be detonation resistant to an experienced engine builder such as yourself great. You're the Jedi engine master - so I'm willing to use the force and stick to plan as long as I fully understand the science behind the madness...

Borg Warner EFR 6258 or the EFR6758 are my turbos of choice, and if we end up with significant displacement with tuning to light the turbo up ASAP - then the larger 6758 turbo should fit the bill nicely. It has excellent boost response, and very long legs so midrange on boost punch should be fantastic.

The VEMS v3.3 is pretty darn sophisticated with excellent ignition timing, but it can also alter injection timing by cylinder if the cam sensor I turned the distributor into works as well as I think it will. (Used a VW one window innards inside the N9TE distributor housing to make it a cam position sensor.)

Rabin

[Bean]

I should also mention the stock log manifold is a beautiful casting that intend to modify to the T25 exit flange. Peugeot used their own flange design which is very close to the T25 dimensions. Plan is to have the stud holes welded in, then drill and tap new t25 pattern holes around the actual outlet. A little fine tuning with the die grinder and it should be perfect.

All the research I found showed the log manifold had the fastest spool, but lost out in top end flow. Since my power goals are modest - the stock manifold should be fine. Once done I'll likely have it ceramic coated as well.

Rabin