Jonny5 Posted February 20, 2006 Share Posted February 20, 2006 Hi firstly I have a UK TT6. Had a dyno session on Saturday at THOR which highlighted a couple of problems. Firstly the car was running slighty rich, which was almost certainly down to the settings on the VPC that is currently fitted. This has now been reset together with an SAFC 2 to provide finer tuning of the AFR. The other problem is the HKS EVC 4 that is fitted is currently set at 1bar low setting and 1.4bar high setting. The engine has been uprated to be able to cope with this boost pressure in the way of HKS forged pistons, camshafts, stage 2 turbos etc.. Now set on the high setting 1.4 bar, Pete ran the car up to find the boost builds quite nicely, 2# turbo starts to spool around 3700 rpm, building up to around 1.1 bar at 4600rpm but then starts to tail off over 5krpm down to about 0.9 bar at the redline. There are no obvious leaks on any pipework, we thought that the first cat was still in place, but it turns out it has been gutted to which I am going to get a proper decat pipe made. Pete tried it with the waste gate pipe disconnected, which should in theory boosted off the scale but there was no increase at all just stayed at 1.1 bar.. As far as I know there are no restrictions in the exhaust it has a second decat pipe on sraight back to a drager. So if anyone could give me any ideas on where to look next I would very much appreciate any help:sos: cheers Jon.. Quote Link to comment Share on other sites More sharing options...
letmeshowyou Posted February 20, 2006 Share Posted February 20, 2006 what did Pete think was the cause? I'd be amazed if diagnosis of this was beyond him! Quote Link to comment Share on other sites More sharing options...
Scoboblio Posted February 20, 2006 Share Posted February 20, 2006 Maybe the gutted front cat can't flow the exhaust gas smoothly enough and creates a bottle neck effect at high rpm / boost? That's a complete guess by the way Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 20, 2006 Author Share Posted February 20, 2006 what did Pete think was the cause? I'd be amazed if diagnosis of this was beyond him! Well we presumed it looked like it was due to the first cat still being in place, therefore not allowing the gases to escape quick enough. But when I got back I split the exhaust to find the cat had indeed been gutted lol.. I think when the pipe to the wastegate was disconnected it was knida head scratchin time. Maybe the gutted front cat can't flow the exhaust gas smoothly enough and creates a bottle neck effect at high rpm / boost? That's a complete guess by the way Yeah could be I guess, I'm going to get a decat pipe made up anyway.. thanks Guys, any other suggestions.. Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 20, 2006 Author Share Posted February 20, 2006 On a plus note though the car is performing alot better since the fueling has been sorted out. It made 360RWHP which at 1.1 bar is not too shabby lol:taped: Quote Link to comment Share on other sites More sharing options...
paul mac Posted February 20, 2006 Share Posted February 20, 2006 ah this would explain why you weren't in on Saturday when i poped round, not to sure how the stock wastegate looks internally jon but an external one with the pipe off will just boost to the spring pressure, would that not be the same with the stock wastegate, what does it boost to with the controller switched completely off, is the solenoid on the boost controller ok dab 12v on and blow through it, is the controller plumbed up right Quote Link to comment Share on other sites More sharing options...
paul mac Posted February 20, 2006 Share Posted February 20, 2006 found this mate http://supraforums.com/forum/showthread.php?t=16723&highlight=low+boost Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 20, 2006 Author Share Posted February 20, 2006 hiya m8, yeah sorry I werent here i popped down top field (Gloucester to see my folks). Managed to pop in to thor lol.. Pete says the boost controller is OK and with it off it was a steady 0.7 bar. I see what you mean though I'm not sure if the wastegate would open to what the spring rate is?? He checked the plumbing and all is well. He reset the boost controller twice and no matter what you set it at 2.5 bar lol..it still won't go above 1.1bar:rolleyes: Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 20, 2006 Author Share Posted February 20, 2006 thanks for the link Paul, looks like a full no vsv and actuator test session coming up lol.. Quote Link to comment Share on other sites More sharing options...
paul mac Posted February 20, 2006 Share Posted February 20, 2006 have you got confidence in that there HKS SSQV as i know where there is one Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 20, 2006 Author Share Posted February 20, 2006 Maybe worth a try M8, I'm pretty confident it ain't leaking now although really it did'nt make much difference when it was..lol.. Maybe worth swapping just to eliminate it though.. Looks like trying the TTC mod may shed some light on it.. Quote Link to comment Share on other sites More sharing options...
bignum Posted February 20, 2006 Share Posted February 20, 2006 Hi jonny, i have a uk 6 and had exactly the same problem last week on thors dyno, im bpu full decat, c/w smic with a manual boost controller fitted in the car.I had it reading 1.1 bar on my gauge but on thors it wouldent go above 1 bar even if we turned the controller all the way out (open), pete even tried 1 of his valves under the bonnet but the boost still wouldent go up, so we thought i must have a leak somewhere. Strange tho on the way home i turned my controller up and got 1.2 bar easely, so ive turned it back to 1.1 and see how it goes. mine also made 360 at just over 1 bar so happy with that. Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 21, 2006 Author Share Posted February 21, 2006 Tried the car in TTC mode, and I get the same boost pressures. High setting of the EVC iV at 1.4 bar I get 1.1 bar same when in sequential.. Incidently the power delivery in TTC reminds me of my 300zx, feels very similar indeed. Can't believe the difference in exhaust note very boomy..lol.. So does this mean there must be some sort of leak somewhere having eliminated the vsv's in TTC mode? cheers Jon Quote Link to comment Share on other sites More sharing options...
Tom Posted February 21, 2006 Share Posted February 21, 2006 Hmmm.... strange one does sound similar to what I had but you say the vsv's are fine? mine would boost up to 0.9 and tail off to 0.7 to redline, I feel I've posted this loads, one sec and I'll dig up some of my old threads too look at then you can do a quick check to see if everything is ok. Quote Link to comment Share on other sites More sharing options...
Tom Posted February 21, 2006 Share Posted February 21, 2006 http://www.mkivsupra.net/vbb/showthread.php?t=49070&highlight=vsv I was running in ttc for a while as I knew my iacv vsv had packed up again so I started playing round with the bleeder t mod and I coudlnt raise the boost in ttc either even though it was working fine, but once I sorted the iacv and back in seq everything was fine again, strange really as it doesnt even come in to play! Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 21, 2006 Author Share Posted February 21, 2006 Yep, is a strange one... I think in the morning I'll try a leak test, by blocking the intercooler hose to the throttle body and pressurising from the intercooler input side and make sure there are no leaks there.. Quote Link to comment Share on other sites More sharing options...
Tom Posted February 21, 2006 Share Posted February 21, 2006 Oh and check that all the plugs are connected too, one of mine had worked it's way off and caused a minor issue! the blue plugs that wire the vsv's up, there's 2 hidden away under the wastegate. Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 21, 2006 Author Share Posted February 21, 2006 I will also double check all the vsv's are working correctly.. cheers Tom:eyebrows: Quote Link to comment Share on other sites More sharing options...
Tom Posted February 21, 2006 Share Posted February 21, 2006 No probs, if you were a few hundred miles closer i'd pop over! Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted February 23, 2006 Author Share Posted February 23, 2006 Well no nearer to getting to the bottom of this problem.. Checked all vsv's seem to be functioning correctly. I've performed a leak test from the air filter and from the inlet to the intercooler and there are no leaks. The only slight leak I found was the EGR seem to be passing, so I've now removed the lot. Relocated the boost controller solenoid valve close to the wastegate cutting down on about 500mm of pipe work lol.. I'm still running in TTC mode so does this effectively rule out the control for sequential anyway?? I've installed a mechanical boost gauge and shes running 1 bar dead on.. Tonight I took the pipe of the wastegate and pressurised it, seemed to be working so far as the rod moving in and out. Went for a drive with the pipe still disconnected from the wastegate and still I only get 1 bar. (should have gone of the scale really) So my thoughts are now, theres either something gone wrong with the #2 turbo internally, the actual wastegate flap is cracked, or slightly open permantly, or perhaps a crack on the exhaust housing(s) although the latter I would presume would be audible.. It's like a definate controlled leak somewhere... Theres no whine, smoke or anything else obvious. Can anyone else throw some ideas at me or shall I start saving for the 'big old single' route...lol:eyebrows: thanx in advance gents Jon. Quote Link to comment Share on other sites More sharing options...
paul mac Posted February 23, 2006 Share Posted February 23, 2006 yo jonny sorry to here of your continuing probs would it be possible to jam the wastegate shut as this would surely eliminate a control problem, your wastegate may be forced open on its own regardless of whether its conected or not Quote Link to comment Share on other sites More sharing options...
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