Jonny5 Posted May 16, 2006 Share Posted May 16, 2006 Well I've stripped everything down today, bar taking the turbos off the manifold lol.. Referring to my previous thread (by the way UK TT 6, de-catted) http://www.mkivsupra.net/vbb/showthread.php?t=59747 I'm still only producing 1 -1.1 bar of boost. I've checked all vsv's for operation they seem to be perfect.. Both turbos seem to turn smoothly by hand, i.e no drag. The only thing puzzling me is the wastegate attached to Turbo 1 seems odd and when pressurized has very small movement say about 10mm max. From the pics can anyone identify if it's a genuine standard UK wastegate or something different perhaps jspec?? I'm pretty much at a loss now, only things I've got left to check is theres no obstruction in the exhaust, highly unlikely as I know it's good from the de-cat pipe back because it is new.. Or one of the turbos is under performing but I wounld'nt have thought this either because there is no evidence of it.. I've tested the intercooler to throttle body pipe work just to make sure theres no leak... Again guys any ideas?? Quote Link to comment Share on other sites More sharing options...
Steviekid Posted May 16, 2006 Share Posted May 16, 2006 Having read your other thread this sounds very similar to the problem I had with my car. I can't help you with regards to it being a standard UK wastegate though! Not sure if it's the same but the J-spec wastegate should start to open at about 10-12psi if you stick a foot pump on one of the connectors and block the other one off. I can't see that there can be anything wrong with turbos themselves if you can reach 1.1bar, especially when you've got it stripped back as much as you have and there's nothing to see. It really does sound like there's a leak somewhere. How did you check the intercooler pipework? Also, how did you run in TTC? If it was by bypassing the VSVs and relying on the pressure tank to open the valves then it wouldn't necessarily rule out the sequential system. I mechanically wired the EGCV and IACVs open and blocked all the hoses leading to and from the pressure tank to completely rule out the sequential system. I eventually traced the leak in my car to the BOV sticking open slightly if you haven't already checked that. Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted May 16, 2006 Author Share Posted May 16, 2006 Cheers for the reply bud, For the last few weeks I disconnected the hose to the wastegate from the boost controller so effectively the wastegate has not been opening at all, suggesting that there is a steady controlled leak somewhere.. I checked the intercooler pipework by blanking the hose from the turbo y pipe which has a nipple so I can connect my compressor to it.. and blocked of the other end with a can, I think it took 2 bar then blew the can out, quite scary when this happens lol. I ran it in TTC, by just bypassing the VSV's, no change apart from louder exhaust..I did notice when I put it back I got a release of air, which must mean the pressure tank is good.. I did have a small leak on my HKS bov which I have now curred and has not made any difference.. Is there anywhere on the intake plenum which could lead to a boost leak, all the hoses do seem intact though.. cheers Jon.. Quote Link to comment Share on other sites More sharing options...
Steviekid Posted May 16, 2006 Share Posted May 16, 2006 For the last few weeks I disconnected the hose to the wastegate from the boost controller so effectively the wastegate has not been opening at all, suggesting that there is a steady controlled leak somewhere.. I did the same thing, drove around with the boost source pipe to the wastegate actuator blocked off and I was only getting 0.9 bar max (with double decat and boost controller). This was while the car was in mechanical TTC mode and like yourself I couldn't see how it could be anything other than a boost leak as I'd had my turbos off before this and they were fine. I found the problem with the BOV (you've no idea how happy I was!!! ) so didn't investigate the intake although it was my next, and as far as I could see, last possibility. Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted May 16, 2006 Author Share Posted May 16, 2006 Cheers M8, I will double, triple check the old bov, but i'm sure is sorted.. cheers Jon.. Quote Link to comment Share on other sites More sharing options...
paul mac Posted May 16, 2006 Share Posted May 16, 2006 you could borrow my blow off while my car is eh currently indisposed, just to make sure ps is the ally welding man in as i need some doing on the intake tube this feckin bonnets driving me mad lol Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted May 16, 2006 Author Share Posted May 16, 2006 Cheers M8, ally welding, Yeah sure I will pop round tomorrow and collect it and get it done for you.. Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted May 17, 2006 Author Share Posted May 17, 2006 Bump, Does anyone recognise the pics of the wastegate I put up..I've just looked at a set of UK turbos in the forsale section and T1 wastegate has a zinc coating on it from the pics, where as mine has a black coating, doesn't look as though it's been painted.. Does anyone think it's worth going a few more steps and taking the turbos right off to check the turbine/exhaust side? cheers Jon. Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted May 20, 2006 Author Share Posted May 20, 2006 Finally got to the bottom of my mystery boost problem. Turns out the wastegate actuator has a weak spring, therefore as the exhaust gases build up to around 1 bar they are pusing on the wastegate flap and therfore limiting the boost. Found the info on supra forums under spring mod, seems the usa guys have the same problem as they have the same twin setup... Ideally I need a new actuator with a spring pressure of around 1.5 bar but I don't really want to strip the turbos down to change it, unless I go single:D So the cure for the problem in the meantime is hooking a fairly stiff spring around the wastegate lever at the end of the actuator rod, then with a long bolt through the actuator bracket, with a hole in to hook the other end of the spring, thereby preventing the flap from being opened.. Works a treat now got it to around 1.3 to 1.4 bar at the mo, only thing is now it's highlighted that I need a new clutch as mine has started to slip lol:rolleyes: cheers Jon. Quote Link to comment Share on other sites More sharing options...
paul mac Posted May 20, 2006 Share Posted May 20, 2006 car was going great jon welcome to the world of overboost:D , start saving for that clutch lol, did you get the disks on and the oil changed ? Quote Link to comment Share on other sites More sharing options...
Jonny5 Posted May 20, 2006 Author Share Posted May 20, 2006 yep oil change done, loverly jubbly;) Thought I'd pop to work to do 'em got all the gear there, lucky i did, 30 mins to the passenger side, fine no problem... come to do the driver side the bloody pad retainer pins in the caliper were fecking seized solid, soaked them in penetrant but no joy, tryed pin punch and managed to mushroom the ends, so had to take the caliper off and perform some minor surgery...Made some new pins and work out of stainless bar but I will get a new set I think to be on the safe side.. I now have zero wobble when pulling on the anchors and the hawk pads are awesome M8, really bite hard, think I will get some rears too lol:) cheers m8;) Quote Link to comment Share on other sites More sharing options...
Steviekid Posted May 21, 2006 Share Posted May 21, 2006 Finally got to the bottom of my mystery boost problem. Brilliant! Great feeling isn't it! 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.
Note: Your post will require moderator approval before it will be visible.