-Welsh-Stealth- Posted October 26, 2011 Share Posted October 26, 2011 It seems like I have a bit of q boost leak. I noticed 2 days ago that I was only making 0.3 bar boost when the car was mapped at 8.5 psi or 0.48bar boost. After realising this I tested the boost to see what the AFR was reading. Thinking it way just be a fault boost gauge.Again it was mapped at 11 AFR and now it's goin straight to 10 AFR which is the lowest my gauge reads. On top of that it seems like it's slipping into det I have recently replaced the stock fuel pump for the walbro, so the car was mapped with the stock pump. Also running stock NA injectors. The dizzy rotor arm and plugs (iridium grade 7) were replaced in august with the na-t build. And the ignition leads (after market)were kept the same...however these have been on the car since ownership in may 09. My thoughts are on the ignition leads being quite old and needing replacing. With lack of spark or poor spark burning off less fuel(10afr) and causing what seems like det?! I'm having a look friday/Saturday to try source the problem. But I just thought I'd see if anybody could offer up some expert advise before I get stuck in this weekend....also off boost it seems fine AFR and driving wise. All help appreciated Lewis Quote Link to comment Share on other sites More sharing options...
-Welsh-Stealth- Posted October 27, 2011 Author Share Posted October 27, 2011 Anybody, anybody dust?! Dust? Anybody? No? Dust, anybody? I wouldn't be offended if I'm wrong. I was just hoping somebody could help shed some light as to where I could start looking to start sourcing the problem Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 27, 2011 Share Posted October 27, 2011 What makes you think it is detonating? Funny ticking noises under boost? If yes, has it got a tubular manifold? If yes, check for cracks, and check for warps at head or turbo flanges, maybe only very apparent if someone tries to seal the exhaust tailpipe with an old wet towel. Just an idea. Quote Link to comment Share on other sites More sharing options...
-Welsh-Stealth- Posted October 28, 2011 Author Share Posted October 28, 2011 Oh dear, sounds about right will try today... But honestly didn't think something like that would happen so early on. Thought heat wrap would help prolong the life Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 28, 2011 Share Posted October 28, 2011 Heat wrap probably makes it worse. I have said for years that turbos, wastegates and exhaust systems hung off tubular manifolds need fully supporting which is an art in itself, and one even the might of Ford and Porsche struggled with. Ford had several revisals of their friction damping plate for the Cosworth Sierra, and Porsche went through hoops with the early 944 turbo cars cracking manifolds. I have yet to see an aftermarket tubular manifold kit that doesn't need a load more fabrication to support the turbo and wastegate(s). Quote Link to comment Share on other sites More sharing options...
-Welsh-Stealth- Posted October 28, 2011 Author Share Posted October 28, 2011 Cheers Chris! Appreciate the offer up of help& advise a conclusion has been reached upon inspection today. The turbo blades where inspected& are fine. The manifold despite heat wrap is fine, along with the down pipe after removal& a good inspection of both. The only reason that could be found was... after the NA-T the car was mapped on a stock pump. which couldn't handle the increased stress after 16 years.so with the walbro fitted it was causing over fueling. And obviously the reason it was running rich& with the excess fuel it was bogging down& struggling to make power..... The car after Dr_Jekyll road shotgun watched the boost gauge make 0.48 & AFR start to go back up to 11.4 from 10. So options I now have are a fuel map or refit a more reliable stock pump. Quick question, I always assumed the heat wrap was an to retaining heat in the manifold but also helped with a more steady cool down? I know extreme temperatures can cause cracking. But I would have thought the heat wrap might have saved the manifold etc from extreme temperature changes on switch off and start up? If this isn't the case do you think it would be better to remove the heat wrap? Or would it depend on what reasons you use the car? For instance track or daily drive. Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted October 28, 2011 Share Posted October 28, 2011 Heat wrap is used to keep engine bay temps down and retain heat in the manifold to increase thermal efficiency. Unless you live in the artic you wont experience extreme temp changes, the manifold should be designed to cope with expansion and contraction. Like Chris said bracing a manifold is the key thing. Quote Link to comment Share on other sites More sharing options...
-Welsh-Stealth- Posted October 29, 2011 Author Share Posted October 29, 2011 Not quite arctic... But we really don't tend to have the best weather here so what can we do in the way of bracing then? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 29, 2011 Share Posted October 29, 2011 ftp://ftp.chriswilson.tv/F1_turbo/ Quote Link to comment Share on other sites More sharing options...
-Welsh-Stealth- Posted October 29, 2011 Author Share Posted October 29, 2011 Aah! Thought that was what you ment seen these before, but not on such a large manifold!? With these, is it a case of custom fabrication? Or do somebody like Titan do these for the 2jz? When I was fitting the mani& turbo to my engine I was wondering if it could hold all that weight... Thanks for all the info Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 29, 2011 Share Posted October 29, 2011 They will have to be fabricated. They SHOULD be part of every tubular turbo manifold kit, but they very rarely are. Quote Link to comment Share on other sites More sharing options...
-Welsh-Stealth- Posted November 2, 2011 Author Share Posted November 2, 2011 Should be- is opportunity to save money lol! I'm sure I can find some parts and have a go quite lucky with the NA TB mounting points What's your thoughts on swapping the walbro back to a stock (new?)fuel pump? Should I wait and get a fuel map in a few weeks? And if I went back to a stock pump would a new fuel filter help with a better flow to the injectors? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted November 2, 2011 Share Posted November 2, 2011 Always fit a new fule filter if you don't KNOW FOR SURE when it was last changed. Walbro pumps are usually very reliable. IF THEY ARE GENUINE!!! Quote Link to comment Share on other sites More sharing options...
-Welsh-Stealth- Posted November 2, 2011 Author Share Posted November 2, 2011 Yep had walbro stamped on it. So new filter& fuel remapped? Quote Link to comment Share on other sites More sharing options...
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