mawby Posted July 31, 2003 Share Posted July 31, 2003 I'm thought the stock setup should produce 0.8 - 0.9 bar? Having just got around to fitting my Apexi EL boost gauge (cheers to eyefi for that, top stuff!) I'm now able to monitor boost and see the peak boost reached. I was surprised after driving home today to see it had peak at 1.08 bar! Previously it had only reached 0.9 bar. Should I be concerned with this? The car is completely stock in that department. Quote Link to comment Share on other sites More sharing options...
Thorin Posted July 31, 2003 Share Posted July 31, 2003 Still have both cats in? Quote Link to comment Share on other sites More sharing options...
mawby Posted July 31, 2003 Author Share Posted July 31, 2003 Yes, as far as I know they are. I'll double check but I'm sure I've seen both of them under there. The car should be stock. I've just paid for a 2nd cat bypass pipe and hks super dragger exhaust, I'm wondering what fitting these to the car will do to the boost. Quote Link to comment Share on other sites More sharing options...
Thorin Posted July 31, 2003 Share Posted July 31, 2003 It will go even higher probably! Previous owner fitted a bleed valve to up the boost or something maybe? Quote Link to comment Share on other sites More sharing options...
mawby Posted August 6, 2003 Author Share Posted August 6, 2003 I've been experimenting with this, and it doesn't do it all the time. The car will quite happly go from 70 leptons to over a 100 leptons without going above 0.9 bar, but then on the way home last night it did it again. It was when I overtook a car that was doing 50-60 leptons, I put my foot down, but not enough to make it kick-down from third to second. As I overtook I gave it a bit more gas and took it up to about 80-90 leptons by the time I got past, all still in thrid gear. Then I looked at the boost guage's peak reading and it was 1.09 bar again! (I had reset it in the morning) Now I also noticed what looked like number 1 turbo (as the revs were below 3,000) pushing out about 0.9 bar today all on it's own! I've had a look at the exhaust and both cats still seem to be in place, whether the Jap owner gutted one or not I don't know. I've also had a quick look around the turbos and can't see anything that looks out of place, all looks pretty much stock to me. Where would this bleed value be if one had been fitted? If the boost goes up to 1.1 bar but never beyond, should I be worried given this is a stock setup? Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 6, 2003 Share Posted August 6, 2003 with both cats in and no bleed valve or boost controller, u should not see more than 12psi it sounds like uv got a leak to either a vsv or an actuator. them little pipes can look ok but still have enough of a leak to make a difference. do a search for "1st turbo boost" or things like that, im sure theres some pics that show which pipes do what. basically u want to look at the pipes which r connected to the wastegate on no1, thats the front turbo and the wastegate is nearest the engine. find that and u should b able to trace the hoses. make sure they r very tight, replace or try cable ties on the connections (pulled very tight cable ties). this is what i would try but obviously i cant see the car. Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 6, 2003 Share Posted August 6, 2003 I wonder if your 1st turbo is overboosting... The first turbo's boost level is controlled by the prespool valve on the second turbo - it bleeds exhaust gas away from turbo #1 to spin up turbo #2. If this isn't happening, you should get overboosting on turbo #1, which sounds like what's going on. As soon as #2 comes online, the wastegate (exactly as eyefi described it) will kick in and bleed off enough exhaust gas from both the turbos to return boost down to stock levels. The turbo pipework stuff is under Resources -> Technical Reference -> FMIC (a tad miselading, that last bit) You are looking for the Exhaust Gas Bypass valve and it's associated plumbing... There is a vacuum path diagram knocking around somewhere too which may help. -Ian Quote Link to comment Share on other sites More sharing options...
Steve Cargill Posted August 6, 2003 Share Posted August 6, 2003 Would the fuel cut be kicking in at just under 1 bar? Quote Link to comment Share on other sites More sharing options...
mawby Posted August 6, 2003 Author Share Posted August 6, 2003 Originally posted by Steve Cargill Would the fuel cut be kicking in at just under 1 bar? I don't notice any fuel cut, I certainly don't get any warning lights come on. Quote Link to comment Share on other sites More sharing options...
Steve Cargill Posted August 6, 2003 Share Posted August 6, 2003 Originally posted by mawby I don't notice any fuel cut, I certainly don't get any warning lights come on. This is what I find odd and think there could be some electronics at play you don't know you have. When fuel cut hits you certanly know about it. Quote Link to comment Share on other sites More sharing options...
mawby Posted August 6, 2003 Author Share Posted August 6, 2003 Cheers for all the replies everyone. I've not had a chance to look closely at the setup yet but I will at the weekend, or hopefully Friday. I did another little experiment tonight. Driving at 40 leptons, pressed the manu button to hold the car in third... and floored it with the boost gauge recording. The playback showed the following... Steady upto 0.8 Jumps to 0.9 Quickly upto 1.0 Drops to 0.6 (About the time 2nd turbo kicks in) Climbs to 0.8 Drops to -0.5 (End of the road!) I'm going to do a slightly longer test tomorrow on the motorway where I'll have plenty of road to see what the boost gets to with the second turbo active. If it doesn't go above 0.9 say, then could it be the exhaust bypass value not functioning correctly? Also, could this cause the tapping noise I described previously, as this occurs at the point where I'd guess the exhaust bypass value should start to open. I don't know. Is there anyone technical going to the Sussex meet or the Hampshire barbecue that could take a look? Hopefully figure this out once and for all! Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 7, 2003 Share Posted August 7, 2003 yep, i think ians right, there's no boost control on no1. either a leak, buggered valve / actuator / vsv. Quote Link to comment Share on other sites More sharing options...
mawby Posted August 7, 2003 Author Share Posted August 7, 2003 Well I did my longer test this morning. Started at 40 leptons, locked the gearbox in 3rd again, and floored it. 1st turbo gave boost up to 0.9, then as the 2nd turbo kicked in the boost dropped to 0.6. Unlike yesterday, I had the opportunity to keep going up to 90 leptons to give the 2nd turbo a chance to do some work, and it did. Right the way up to 1.2 bar! Still no fuel cut! But I'm worried this might damage the engine regardless. I checked the turbo pipes quickly this morning and all seemed tight, with the exception of the one marked as "From Wastegate VSV" in this picture. It wasn't lose in the sense of falling off, but it was the only hose that I could turn around the pipe, all the others where fixed fast and wouldn't budge. Could this hose have anything to do with it? But that still wouldn't account for the lack of fuel cut would it? Quote Link to comment Share on other sites More sharing options...
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