Stewart Posted July 6, 2014 Author Report Share Posted July 6, 2014 Saturday morning seemed to work this time. Here is the progress and a drawing of what I'm aiming at. 4x shortish runners into a chamber of close to the volume of 2 runners sitting inside the RHS which will surround the "log" / plenum as a sturdy turbo and pipe mount as well as a very good heat retention manifold cover. I plan on beadblasting inside and out and also using VHT manifold coating process which uses ceramic particles and then fitting heat shields to the assembly. Quote Link to comment Share on other sites More sharing options...
andrethx Posted July 6, 2014 Report Share Posted July 6, 2014 very cool! by the way, i found a picture on the internet of you working on this: andré Quote Link to comment Share on other sites More sharing options...
Stewart Posted July 6, 2014 Author Report Share Posted July 6, 2014 Ah jest lurve Jethro Bodine. Although ah like Ellie May aloooot better! Jethro and I have a lot in common too. For instance, we both have inquiring minds , drive Jalopys and like dressing up in aprons. I don't have any kin folk thet look like Ellie, though. An Ah dont heve no rich Uncle niether. Dang it..................................... The Benny Hill theme tune suits me, if one imagines a certain Dimwit from Down Under, toiling away on a certain dark red 404, it gives a true yet sorry picture of my good self !!!!!!!!! Quote Link to comment Share on other sites More sharing options...
Stewart Posted July 8, 2014 Author Report Share Posted July 8, 2014 On turbo manifold design I found this, http://www.tercelreference.com/tercel_info/turbo_exhaust_theory/turbo_exhaust_theory.html In practice using some of the positive changes should give a nice result! Quote Link to comment Share on other sites More sharing options...
Stewart Posted July 12, 2014 Author Report Share Posted July 12, 2014 Here is the almost finished product. 4 runners into tapered chamber, feeding T25 underneath. Bean, I made an insert to directly to feed the outlet into the stainless down pipe. I also made up a split outlet pipe set up of stainless as you suggested. Some further plumbing, beer, grinding, beer drinking and ceramic painting before some beer and it will look pretty cool while I have a beer. Should hammer that turbine ( after I get some more beer .) Quote Link to comment Share on other sites More sharing options...
Bean Posted July 13, 2014 Report Share Posted July 13, 2014 I tried to find some info on plenums used on the exhaust side, but I couldn't find anything... Most designs I was thinking of use 90 degree and / or "T" weld els with no plenum as you have it set up so I'm very curious to see how it works. Have you thought about tapping the exhaust manifold to measure manifold pressure? Diesel guys do it to make sure they dont boost more than double manifold pressure, so curious if that would be a good measure to look at with a new exhaust manifold design. Rabin Quote Link to comment Share on other sites More sharing options...
Stewart Posted July 15, 2014 Author Report Share Posted July 15, 2014 I guess what the idea is to firstly make the thing and to do that myself and then have something sturdy enough so as I don't have to do it again. And I want to give my cam a fair chance at proving itself. It had to fit in that small engine bay and I also have to get a 2.25" down pipe down past the steering too. The plenum is only 840 cc and each pipe is 285cc so it is just a little larger in volume to a log manifold. Will fill you in on the thinking after I get some family stuff done with. Quote Link to comment Share on other sites More sharing options...
Stewart Posted July 19, 2014 Author Report Share Posted July 19, 2014 Here goes with the thinkin and sypherin I been done busy at with Ellie May and Granny out beside the cement pond last week, I had tuned length pipes which were leaking and needed a lot of work so after the turbo started to smoke a change was due. I'm using the header plate off the pipes and found some heavy wall mandrel bends and pipe to suit the new manifold. Ports are 38mm and pipe is either 36 or 41.6mm with 3.2mm wall so I went for 48x3.2 pipe which gives 41.6mm ID. That gives me an anti reversion face at the head too . with space and weight issues I decided to see if it could be done with a simple to make layout and tune the volumes as I went. The turbo sits under some 75 x 50 rhs wih 2.5mm wall thickness. The equal length runners exit into the rhs which I sliced to give a drop feed angle from the rear towards the turbo inlet. The outlet pipe is stainless separated from the wastegate which runs a 25mm tube about 400mm beside the exhaust to converge again into the main to travel past steering into a 63mm (2.5") pipe. The ideas are that the 4 equal pulses for one don't have much effect on each other in the respective ports as a log will have, then the hot exhaust pushes through the turbine to exit into a low pressure bigger pipe. The manifold should stay hot due to the material but also the dump pipe is directly under the small plenum heating it as well. It will get a ceramic coating and probably a heat shield if needed. Some reading suggests a turbine inlet temp of 660 C and header temp at 870C so I'll have to set up an EGT sensor as well as the wideband.. Pretty cool stuff once all the hard labour is done. I have a divergent cone I machined up to get up close to the turbine exit and expand at 7 deg included angle into the stainless outlet pipe. 43mm to 47mm. It will close off the wastegate flow from the turbine flow so that should be a positive step. I purchased a decent belt grinder/linisher yesterday so it should pay for itself with this job and the next.All the turbo faces were distorted too so the new tool fixed that up! Quote Link to comment Share on other sites More sharing options...
Bean Posted August 17, 2014 Report Share Posted August 17, 2014 Looks great Stewart! I look forward to hearing how the beast works once you have it all installed and running. Particular interest will be the boost response of this new set up... Rabin Quote Link to comment Share on other sites More sharing options...
Stewart Posted August 19, 2014 Author Report Share Posted August 19, 2014 This really dragging on now. Manifold and twin exit dump done. K sensor installed at turbine inlet and plumbing for the heat exchanger is down on paper to make this week. Putting a repair kit into the T25G this week too. It had zero wear but the end plate ( 360 deg bearing) cracked as I was assembling. Manifold , turbine housing a down pipes are coated in ceramic paint and cured. I also wrapped the down pipes to keep 'em hot. I'm trying to get the turbo oil and coolant feed fittings sorted but it's just dragging out as I can't find any one interested enough to supply such insignificant items. 2 weeks in for that stuff alone! It may be running on the weekend though. 10 psi first up to tune in the mixture. I am pleased to report however the work I've been doing recently on distributor and carb rebuilds has proven the Dynosim 5 Ignition figures to be quite close to real world perfect. Quote Link to comment Share on other sites More sharing options...
Bean Posted August 25, 2014 Report Share Posted August 25, 2014 How'd you make out this weekend? I'm dying to see if this combo has the characteristics you want. VERY curious to hear how the exhaust manifold works out especially as well. Rabin Quote Link to comment Share on other sites More sharing options...
Stewart Posted September 2, 2014 Author Report Share Posted September 2, 2014 This weekend was mostly basketball travel for Dad and boy. however this afternoon got me a little closer to an end for this. I rebushed the tiny T25 a while ago and have been plumbing the oil and coolant system since. Intercooler mounts and plumbing next but, the bast##d thing is very close to running again. I have a K sensor at the turbine inlet, new ideas for intercooler plumbing but haven't done a bypass valve or air filter yet. Close now, I guess. Pretty confident of excellent flexibility, quick spool and smooth delivery of a big heap of fat torque. What do you think, Old Chap? Quote Link to comment Share on other sites More sharing options...
keebs Posted September 2, 2014 Report Share Posted September 2, 2014 That's a pretty clean setup. Might I suggest a 2nd thermocouple in your hottest predicted runner as cheap insurance. Due to gas re-compression at turbo inlets it can be difficult to guesstimate the actual egt. The expected difference between the primary and turbo inlet temps is 50c or more with the turbo inlet being the hotter one. Quote Link to comment Share on other sites More sharing options...
Bean Posted September 2, 2014 Report Share Posted September 2, 2014 Looks very close Stewart! I'm assuming the reservoir beside the manifold will be heat shielded - or is the ceramic coating sufficient? Keebs - the second t-couple sounds like a good idea if tuning to the edge, but for a relatively low boost (12psi correct?) street motor do think its still necessary? Stewart - if you get a chance to shoot some video of this beast I'd LOVE to hear it run and see it go. Rabin Quote Link to comment Share on other sites More sharing options...
keebs Posted September 2, 2014 Report Share Posted September 2, 2014 Tuning to the "edge" is a bad term. As an example many times when a turbo is added to a na motor egt isn't used which is fine. The problem is when the ignition map is set to too little advance under boost and make "safe" a tune. Sure now you wont have det but your egt could be through the roof which is now burning your valves. So the "edge" really goes both ways when it comes to tuning. For a proper tune egt, afr, and det cans should be used. Quote Link to comment Share on other sites More sharing options...
Stewart Posted September 2, 2014 Author Report Share Posted September 2, 2014 Keebs, thanks for the suggestion and your interest. I made the manifold as an expansion chamber to a tapered log feeding into the turbine so hopefully I can get gas temp down to 860C before the snail. It is a good idea for a second thermo, now you mention it! The engine is already closley tuned so hopefully there won't be too much drama in tuning back in. I read a lot of stuff regarding tuning a T25 and found that 860c at turbine inlet is about max temp for the little T25G. I'll dig around later today and post the article up here. Innovate had one on mixture and ignition timing too, so I'll see if that is available for us to ponder as well ! I'm looking forward to hearing the run again Bean! Quote Link to comment Share on other sites More sharing options...
keebs Posted September 2, 2014 Report Share Posted September 2, 2014 Your manifold is a good design and should perform nicely. Safe egt out of the primary should be 850-900c for continuous use. What kind of engine management are you using? Quote Link to comment Share on other sites More sharing options...
Bean Posted September 3, 2014 Report Share Posted September 3, 2014 Excellent info Keebs. Curious - are you in the field as well or just experienced enthusiast? Id be curious in seeing details on cars you've built / worked on as well as any insights on experiences with stand alone ECU's. I picked up a VEMS system for my absurdly long build, but now I'm somewhat tempted to retrofit Bosch LH 2.4 off a later Volvo and just get it tweaked a bit. Rabin Quote Link to comment Share on other sites More sharing options...
keebs Posted September 3, 2014 Report Share Posted September 3, 2014 I'm both in the field and an enthusiast. I've built 2 stroke moto engines, small block chevys, and some marine diesels here and there. Soon I'll be building a fairly stout n9t. As for stand alones everyone has there preference. Most of the units are pretty good these days, so it really comes down to the tuning software. I'm actually using vems on my turbo with 630cc injectors, original tps, and bmw 3 wire iac. The hardest part was removing the factory harness and finding the wires that needed to stay. If you already have vems use it. Sure a retrofitted bosh system would run, but it would never be right. Warm up enrichments, accel enrichments, ignition curve, maf scaling etc would all be wrong. I say this with confidence as a factory trained tech that specializes in electronic diag. Quote Link to comment Share on other sites More sharing options...
Stewart Posted September 3, 2014 Author Report Share Posted September 3, 2014 Keebs, looks to me you've been down this road a lot more than i have and I'm very greatful for your input in this. I have a det can ready I had made up for when I get close, as luck would have it! The plan is to run the Link G3 in an auto mixture tune on the road after I reduce the ignition map 4 degrees, then lift the map back up. I was going to the dyno but perhaps I'll try the det can first to get it close for the tuner. This a little while away yet though as I'm still making the intercooler plumbing and mount. I'd like to share these articles with you and ask your opinion please. http://rusubaru.com/egts-101/ Innovate have a piece on ignition timing and egt, http://www.innovatemotorsports.com/resources/myths.php Quote Link to comment Share on other sites More sharing options...
keebs Posted September 4, 2014 Report Share Posted September 4, 2014 Those articles are very informative. It is true extended temps over 900c can cause problems one of which is deformation. Turbo manifold pressure is around 3x boost pressure, so if you boost 12psi the manifold will register 36psi. This can lead to a glass blowing effect if too hot. If your not road racing bursts of 950c are probably fine but not ideal. For afr keep in mind cam overlap can affect it. O2 and fuel slips through the cylinders and into the exhaust showing a leaner read. This is why it is always important to take plug readings while tuning. The boost portion of the ignition map is easy to tune. Creep up to the det limit take out 2 degrees and watch egt. It will have to be done a few times over the year at different temps to get a truly dynamic map. Link ecu is nice, should have every feature you'll ever need. Quote Link to comment Share on other sites More sharing options...
Bean Posted September 4, 2014 Report Share Posted September 4, 2014 Keebs - the fact you're going to be running the same engine management system with similar tune makes it a no brainer for me. Nick Cota currently has my system on his #45 race car engine but I think the build has stalled out. Plan was to lend him my set up and he'd install it and have it tuned by the North American distributor for VEMS that he knows well. I'd then get the system back with a tune that is pretty darn close. I don't have a dyno close, and while I have a lot of theoretical knowledge, I seriously lack the time needed to really sort it out If you have the chance to detail the continued changes to your 505 that would be awesome. With people like yourself and Stewart with seriously deep experience and knowledge levels working with these cars I'm hoping that the potential in these cars can be realized. Now - about this stout N9T you speak of, I need details man! I know the engine pretty well from when August owned the car so curious if it's staying as is with proper ECU and tuning or if you're planning on doing anything different? Rabin Quote Link to comment Share on other sites More sharing options...
keebs Posted September 4, 2014 Report Share Posted September 4, 2014 Vems setup is pretty straight forward. I'm using the stock dizzy as the primary trigger with a single inductive coil. With the ported head and danielson cam the stock log manifold just doesnt cut it. Above 4500rpm when the cam starts to breathe egt steadily rises from 850c and I'm regularly seeing 950c between #1 and the collector. A ramhorn or mini ramhorn would probably free up near 20hp. For the build I'm going to try to use 2jzgte rods, forged 92.5mm mitsubishi starion pistons, lightened flywheel, and a better head gasket. Quote Link to comment Share on other sites More sharing options...
Stewart Posted September 4, 2014 Author Report Share Posted September 4, 2014 Cool Keebs. I'll have a think about an exhaust dimension for you and (my favourite hobby) cam timing . Advancing the cam might just open it up. If thats OK. Then I'll run it through the Dynosim 5 and you can check numbers against what you have in VEMS? Quote Link to comment Share on other sites More sharing options...
keebs Posted September 4, 2014 Report Share Posted September 4, 2014 That would be great. I think cam timing needs to be slightly retarded. I dont have an adjustable gear so I'll have to loosen the lash. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.