2G GSX Auto brake boosting problems.

[Kdouglas89]

Hello guys, gonna give basic run down of relevant mods followed by the question. My profile is updated with a complete list, just naming only things relevant.

Built supertech head with HKS 272
Stock block
Stock tranny
Ported 16G, 1250 injectors, on 255
Dsmlink
Speed density
Running E85 on bpr7eix i think is the number.


I am unable to build more than 2lbs of boost at 2400RPM on stock converter at the line. My AFR is 13.2 during brake boost. Have been advised to drop it down to mid 12's, and swap my plugs to copper br6's.

Having a big debate between other DSM'ers about if I will have to swap out my converter to be able to build 10-15lbs off the time.

Have also tried to retard timing off the line to like 12 or so. I was unable to build boost after the change. Have been told retarding timing for a 16g would not do anything.

 

[91stocker]

I appreciate all the responses guys!

1. I have done an exhaust leak test "Put BLT at end of exhaust tip, and pushed air through." Only leak was turbo to o2 housing. "Im internal wastegate".
2. I boost leak tested up to 20lbs, there is not even a small leak.
3. I just tried my friends 16g wastegate with same results. I also tried adding a couple washers to the wastegate to tighten it, same results.
4. Friend and I messed with the tune, and was able to build max of 4ish psi with anti lag. I always thought you wanted to richen fuel to boost, not lean it out?
5. I was not going 100% wot on the line because I was building same rpm / boost regardless.
6. I am on stock intake.

I am starting to think it actually is my torque converter unless somehow my tune is wayyyy off, but I don't see how.

Also, the turbo was rebuilt / bored / clipped from forced performance about a year ago. There has been maybe 150 miles on it since. Absolutely no shaft play. I would be extremely surprised if the turbo would be causing the issue.

Well the list of possible problems gets shorter.

But in response to #4.

You need torque to get over the hump. 13.2 is too lean to make good power. So in your case you do need to richen it up a bit. About a point and a half.

But you still need to figure out why it spools like an hx40. Maybe the 13.2 afr's are the culprit. Whats your target afr's at wot?

The converter is still a possibility, but usually when the converter goes you stall too high and/or slip and overheat. Usually makes a hell of a racket too.

 

[Kdouglas89]

Well the list of possible problems gets shorter.

But in response to #4.

You need torque to get over the hump. 13.2 is too lean to make good power. So in your case you do need to richen it up a bit. About a point and a half.

But you still need to figure out why it spools like an hx40. Maybe the 13.2 afr's are the culprit. Whats your target afr's at wot?

The converter is still a possibility, but usually when the converter goes you stall too high and/or slip and overheat. Usually makes a hell of a racket too.

During WOT I like to be around 12.

I am going to post another log of a WOT pull tomorrow after tightening the actuator to see if it helped at all. I noticed a bit of a difference, but did not do any major pulls while logging to see.

I 100% agree there definitely is an issue with spool, but to me, everything is looking like it checks out.

Is there anything sensor related that would cause the stall issue? I am not running kiggly mod or anything. TCU perhaps?

Thanks as always
Kevin

 

[Kdouglas89]

Would turbo to o2 housing leak cause boost issues? Just spoke to local turbo rebuild shop, and he said it would cause issues, even on internal wastegate.

I really have no interest in dropping the turbo to fix that leak if it won't effect anything. I was under the assumption since it was past the turbo, it wouldnt do much.

You must be logged in to view this image or video.

 

[Kdouglas89]

From the looks of it, I do have an exhaust leak. I pushed air through exhaust tip, and sprayed soapy water and it didnt appear, but the dark stains says differently.

You must be logged in to view this image or video.

 

[SS Laser]

I will be shocked if that it the TOTAL fix. Is that a problem, sure. Just not seeing it being the only reason for your issues. Can't wait till you get it back together and do more testing. Good luck!

 

[91stocker]

A bad tcu usually puts the car into limp mode.

From the looks of it, I do have an exhaust leak. I pushed air through exhaust tip, and sprayed soapy water and it didnt appear, but the dark stains says differently.

And the list of possible issues gets even shorter. Hope that takes care of it. Good luck

 

[Kdouglas89]

I will be shocked if that it the TOTAL fix. Is that a problem, sure. Just not seeing it being the only reason for your issues. Can't wait till you get it back together and do more testing. Good luck!

Thanks man! This issue is definitely one of the more irritating things Ive come across. Gonna put all new gaskets and slap her back on. Keeping my fingers crossed hoping this actually will solve it. This TN heat is definitely not motivating me though.

 

[Cox Abele]

I'm extremely interested in what the fix is since I'm in a very similar position.... 272 cams installed straight up, TD06SL2 20g, no boost leaks to 30psi and 3 psi of boost no matter what I do to the tune. Please, don't forget this thread!!

 

[93 GSX TURBO]

Just saw this thread from my personal experience, it is your cams that are the issue.

With stock cams I was able to get the stalled up and launching with around 18-20psi.

I then installed CROWER 264/272 cams and was only able to build about 10psi off the line.

I then swapped over to HKS 272s and launching around 12-13psi.

Ive tried changing timing both ways and on link at the those specific RPM points and also adjusted A/F ratios every which way. I have done a boost leak test and everything is fine there. I have checked for exhaust leaks and also good on that end too.

So from my personal experience I would say the you and I have the same issues, our cams are made for top end/higher rpm gains. Ive been tempted to swap over back to the stock cams because of this, but the 4-6mph gain through the traps makes is hard to go back.

 

[SS Laser]

Just saw this thread from my personal experience, it is your cams that are the issue.

With stock cams I was able to get the stalled up and launching with around 18-20psi.

I then installed CROWER 264/272 cams and was only able to build about 10psi off the line.

I then swapped over to HKS 272s and launching around 12-13psi.

Ive tried changing timing both ways and on link at the those specific RPM points and also adjusted A/F ratios every which way. I have done a boost leak test and everything is fine there. I have checked for exhaust leaks and also good on that end too.

So from my personal experience I would say the you and I have the same issues, our cams are made for top end/higher rpm gains. Ive been tempted to swap over back to the stock cams because of this, but the 4-6mph gain through the traps makes is hard to go back.

So glad you seen this with the cam swaps! I think it is the cams also. Also very interesting to me that the Crower split set up would build less boost then the HKS 272's. Did you notice a "time" to build that boost also change? As in with the bigger cams it takes longer to get to say 10psi then it did with stock cams?
Do you have cam gears to try and improve the stall psi any? Thanks for your input sir!

 

[SS Laser]

I'm extremely interested in what the fix is since I'm in a very similar position.... 272 cams installed straight up, TD06SL2 20g, no boost leaks to 30psi and 3 psi of boost no matter what I do to the tune. Please, don't forget this thread!!

Because I understand no one wants to change cams your best bet is to play around with adj cam gears to see if you can get it better that way. The was a really good thread on here about a member that was very good at dialing in his cams with adj gears. But I lost my saved threads after the forum change so I don't know what the thread was called. Sorry. And I have no idea were to tell you to start adjusting the cam's.

 

[Cox Abele]

I fully intend to have my cams adjusted. I've got a set of HKS adjustable gears itching to go in once I start really working on the car again. Manley springs and retainers will be going in at the same time. While I could optimize my setup, I'm planning to also swap over to an HX35, FP exhaust manifold, tial external gate, Tial Q Bov (over a stock 1g) and speed density. 80% of the parts are hear minus gaskets, water line delete and the SD. Once it's all in, I'm going to have the cams adjusted and car tuned on a dyno- if it still won't spool, I'll kick up a 25 dry shot which is also on here.... I'm just really interested if the obvious solution all this time was cam timing.

 

[SS Laser]

I fully intend to have my cams adjusted. I've got a set of HKS adjustable gears itching to go in once I start really working on the car again. Manley springs and retainers will be going in at the same time. While I could optimize my setup, I'm planning to also swap over to an HX35, FP exhaust manifold, tial external gate, Tial Q Bov (over a stock 1g) and speed density. 80% of the parts are hear minus gaskets, water line delete and the SD. Once it's all in, I'm going to have the cams adjusted and car tuned on a dyno- if it still won't spool, I'll kick up a 25 dry shot which is also on here.... I'm just really interested if the obvious solution all this time was cam timing.

It depends what is acceptable boost and time to build that boost if adjusted cam gears will work for you IMO. If it still is not good enough for you I would try a set of "264" style cams or even stock cams with a stock tight converter. All this is my just my opinion. No hard evidence to back it up. But good luck to you and please come back and post up your results when your mods are all done!

 

[Kdouglas89]

I'm extremely interested in what the fix is since I'm in a very similar position.... 272 cams installed straight up, TD06SL2 20g, no boost leaks to 30psi and 3 psi of boost no matter what I do to the tune. Please, don't forget this thread!!

I will keep this thread updated! I know a lot of Auto guys have similar issues, so I will do my best to figure out what is going on here. I sealed everything back up with new gaskets and the copper gasket maker. Will be mount back up the head Today or tomorrow and will update with results.

Kevin

 

[bigdnno98]

Yeah, I'm really at a loss here as I know nothing about AT DSMs. Basically we've tried everything that I can think of. It's going to take someone with way more AT knowledge than me if this doesn't fix the issue.

 

[enriquez2000]

So im in a similiar situation with a 1g.. chump suggested leaks for me or compression as well. I did fix something strange which was my vacuum line to gate was shredded. I was still boosting to 20psi normally like that. Now that its fixed it creeps to 23ish tha falls back to 20.

The thing is i can now brake boost to about 7psi while boosting but while watching my afr it drops to 12.6 which i do target 10.5 on wot but 12.6 is way off from the 14.7 it should be so im hoping some tuning will help with what im reading here.

On 2 step for the honda we retard timing by 5 and enrich fuel by as much as 10percent(some people go crazy but i can hit 20psi on a 62mm quickly) to increase the fireballs spooling the turbo. Wouldnt the same hold true here? And if so wouldnt my afr be helping?

 

[Kdouglas89]

Just a quick update.

I installed everything and when I turned on the car it sounded and felt weird. The WB AFR's are reading fine, but link is shooowing my fuel trims at 16.8. My o2 does not cycle much. I have tried resseting long turn trims but didnt help. Wondering if my tune was way off to compensate for my exhaust leak. Will be looking into it further soon. Will not try brake boosting until I get this new issue figured out.

Kevin

 

[Kdouglas89]

I got the tune all straightened out and tried to brake boost with no luck. I now have no exhaust leaks and still am unable to boost past 4 pounds. Looks like I will be in search of a new converter. I am doubting the 272's would restrict me to 2300~ rpms.

 

[1990TSIAWDTALON]

Ok, I don't have a auto but my son does. He blips the throttle to start the spool and lets off then gets back in the throttle again about 1/2-2/3rds and it does take a few seconds, more than 5 but he gets around 10 lbs and as soon as he gets off the brakes and e-brake (it takes that to hold the car back) it builds quick. This was on a 20g turbo and I believe BC280 cams, 8.5:1 compression. I talked with him about this last night. Just his experience. Google "Matt Wilson goes 12.81 at MoKan" and maybe you can see his stage. He had valve seals going out so it was smoking a bit but its a good video of how he stalled AND how long it took him. I had to talk to the starter at the track so they understood why he didn't stage quickly and they were accommodating. Just MTC. Maybe it will help.

I just looked on my phone through Google and it comes up "Matt Wilson - Sinister TSI runs 12.81 vs Mustang - YouTube"

http://m.youtube.com/watch?v=nEBC-M7fZCg I think this is it, can't go to YouTube on my work computer, Internet police are blocking me. Sorry but I'm trying.

 

[boost97gst]

I'm gonna say what honda_burner threw out: Check for restricted exhaust flow.

 

[1990TSIAWDTALON]

Yes, Matt was running open exhaust on his 97 Talon so make sure your restriction free.

 

[Kdouglas89]

I'm gonna say what honda_burner threw out: Check for restricted exhaust flow.

I will be checking into this next. I do have a cat. The piping around the cat looks significantly thinner then the rest of my exhaust.

Kevin

 

[SS Laser]

I got the tune all straightened out and tried to brake boost with no luck. I now have no exhaust leaks and still am unable to boost past 4 pounds. Looks like I will be in search of a new converter. I am doubting the 272's would restrict me to 2300~ rpms.

Yes sir try a converter. Let us know how that goes also please. The more info the better. Also try some adjustable cam gears. I think that will help also IF adjusted for more low end torque. Good luck. As a side note from reading a few different threads I think this problem pops up more on a 2g. A 1g stock converter must be a tad looser IMO. But there was 1g dsm I know of first hand that had this issue also. But he changed to much for me to pin point his problem. Just like the 2g I know that had this problem first hand. Something I just though of though was the could build the boost past the 2500'ish stuck point but it just took forever sitting on the brakes! Not sure the peak boost at this time though.

 

[1990TSIAWDTALON]

You WILL have to sit on the brakes. My son had a 9" Sinister Speed converter and still it took quite awhile to build any reasonable boost but when it did it took everything to hold it back!

 

[jery1234]

Just re stall the convertor & don't look back . My 2g runs on re stalled one & I don't have any problems stalling it to whatever boost in about 4.5 sec . I'm 2.3l but my turbo is 6466 gen2 1.15 ar . If you have a cam gears try to retard exhaust cam 3-4 * it will help.