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.

 

[boost97gst]

Who restalled your converter? What would you suggest for a street/strip build 2.0L. It'll be in the 500whp range
Hijack......maybe the OP can use this info as well though?

 

[Chumpaumpalumpa]

Who restalled your converter? What would you suggest for a street/strip build 2.0L. It'll be in the 500whp range
Hijack......maybe the OP can use this info as well though?

http://www.importperformancetrans.c...ustom-high--stall-torque-converter.-1734.html

 

[SS Laser]

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!

I disagree with the right combination of parts. But what I was talking about is WAY to long sir. Not in 3 or 4 sec's. Like taking 8 to 10 sec way to long there for us.

 

[Kdouglas89]

Update!
I just built 2800rpm - 8.5lbs of boost on 19 degree timing. This is without using anti-lag / 2step. I was not able to build much boost using anti-lag, so I will not be messing with that anymore. WOOHOO. We are getting there boys!

Edit : For anyone not following - I removed my Down pipe off my O2 housing and I was able to rev out more, and build more boost. It looks like I was being highly restricted. I am not running a cat either.

 

[bigdnno98]

Crazy an already cat-less exhaust has that much affect on spooling a turbo off the line. Maybe I should just put mine out the bumper

 

[SS Laser]

Sounds like it has a stock downpipe? Taking 9 sec'ish to build that you better have a good trans cooler with good fluid IMO. That's to long to sit there burning up the trans. Get a good 3in DP and exhaust. And some adjustable cam gears or swap out cams. And I did not see antilag that I am use to. That is a stutter box with fuel cut. You need an ignition box with ignition cut for an auto IMO.

 

[bigdnno98]

Sounds like it has a stock downpipe? Taking 9 sec'ish to build that you better have a good trans cooler with good fluid IMO. That's to long to sit there burning up the trans. Get a good 3in DP and exhaust. And some adjustable cam gears or swap out cams. And I did not see antilag that I am use to. That is a stutter box with fuel cut. You need an ignition box with ignition cut for an auto IMO.

It was cutting ignition. 18* to -10*. granted I don't think it's setup the way our friend here has his setup. His is a manual car with an auto swap so it has an actual clutch switch to use the anti-lag the way it was meant to. He should be fine on a 16g with no AL needed. Doubt he feels like re-timing that motor either so I doubt cam gears is happening. We'll mess around with timing and see what works better at the line to build the most boost without blowing through the breaks. We need to get this thing on a track now!

 

[Kdouglas89]

Sounds like it has a stock downpipe? Taking 9 sec'ish to build that you better have a good trans cooler with good fluid IMO. That's to long to sit there burning up the trans. Get a good 3in DP and exhaust. And some adjustable cam gears or swap out cams. And I did not see antilag that I am use to. That is a stutter box with fuel cut. You need an ignition box with ignition cut for an auto IMO.

I have no idea if it's stock DP or not. I bought the car totally stock except for the exhaust. The diameter of the down pipe does look extremely small though. I will be messing with the tune a lot more. I do have a trans cooler, but holding it that long also makes me nervous. Adjustable cam gears may be an option if tuning doesn't do what I need it to.

Kevin

 

[SS Laser]

Good luck guys let us know how it goes! I am out of idea that would help.

 

[SS Laser]

It was cutting ignition. 18* to -10*. granted I don't think it's setup the way our friend here has his setup. His is a manual car with an auto swap so it has an actual clutch switch to use the anti-lag the way it was meant to. He should be fine on a 16g with no AL needed. Doubt he feels like re-timing that motor either so I doubt cam gears is happening. We'll mess around with timing and see what works better at the line to build the most boost without blowing through the breaks. We need to get this thing on a track now!

Why in such a hurry to have a bad track outing? Been in to big a hurry before myself and the track day was never good. My advice is get things working well then hit the track. But that is just a old guy talking. Also you can switch cam gears with out re-timing the engine I think. I will look for that thread. http://www.dsmtuners.com/threads/cam-change-without-loosening-timing-belt.446552/ This should give you the idea. I guess with gears you might want to re do the timing marks. Thought it was just like a fast cam swap but I was wrong. Good luck guys keep us updated.

 

[91stocker]

Update!
I just built 2800rpm - 8.5lbs of boost on 19 degree timing. This is without using anti-lag / 2step. I was not able to build much boost using anti-lag, so I will not be messing with that anymore. WOOHOO. We are getting there boys!

Edit : For anyone not following - I removed my Down pipe off my O2 housing and I was able to rev out more, and build more boost. It looks like I was being highly restricted. I am not running a cat either.

Congrats. Glad to hear that you're getting it figured out.

What do your afr's look like while on the brakes now that that exhaust leak is fixed?

 

[Kdouglas89]

Congrats. Glad to hear that you're getting it figured out.

What do you afr's look like while on the brakes now that that exhaust leak is fixed?

I don't think I had a bad enough exhaust leak to affect AFR's. I did not have to change much in my tune to get it back to 14.7 at idle. As noted above, my afr sensor is on my DP which I disconnected during my test. I am glad I'm on the right track to figuring out this issue, and I really hope this thread gives other people a good starting point to look if they are having similar issues. There are not very many threads regarding brake boosting an AT, and how to solve issues on it.

Kevin

 

[Cox Abele]

It's been another month and I'm still following this thread as I slowly put my setup together. Any additional progress?

 

[bigdnno98]

Nope. Have the 3" Megan DP on it and went external WG. Still no boost. Gotta either be the turbo or TC.

 

[Derail20T]

I was having a similar issue after doing an auto swap last fall. I didn't have any issues spooling up a 14b, but when I installed my 20g I could only spool up when my iat's were very cold, like 70°F in the early morning. I tried everything, adjusting timing and a/f ratios and even antilag settings but nothing worked. I believe that having a sheet metal intake manifold and aggressive cam hurt the situation even though I have a restalled torque converter. I could only stall to 2800 rpm and could online build 5 psi of boost. To solve mymy problem I finally decided to do what so many others have, I installed a Nitrous kit with a 35 hp shot. I have only tested it out last night but with the nos I can easily spool up to 4000 rpm and build 20 psi of boost. I got rained out at the track last night so I don't have any other results but I am very happy that I made the choice to use the bottle...

 

[Kdouglas89]

The thing is, I removed the stock DP from the o2 housing and I boosted to around 10lbs at 2800rpm, so I figured I solved my issue. I purchased the Megan racing 3" DP, installed it, and I was back to square 1, still no boost . I have since tore the turbo apart and did not notice any cracking at all, and have put on a External WG / o2 recirc. I am steering away from thinking it's the turbo due to me being able to spool up to 10lbs. It is very strange that I could spool with an open o2 dump, but not with the 3" megan connected.

Kevin

 

[SS Laser]

So open O2 housing is 10lbs of boost. 3in DP open is much less boost. I would not have bet on that with a 16g. WOW! Keep us updated please.

 

[bigdnno98]

It's the weirdest thing man. I've never seen anything like it. I'm starting to think its the turbo.

 

[SS Laser]

Anyone with a 16g around you could throw on to see? I still think it is cam timing or cams. Still thinking about the full boost at 5k.

 

[bigdnno98]

Yeah he's grabbing a 16g today to try.

 

[Kdouglas89]

Anyone with a 16g around you could throw on to see? I still think it is cam timing or cams. Still thinking about the full boost at 5k.

I appreciate your interest in my issue haha! My parents came in from out of town, so I unfortunately have not been able to throw on my friends 16G yet. I hope to do it tomorrow if it's not to hot outside. I will keep this thread updated as always. Thanks Michael "Bigdnno98" as well for keeping it updated

 

[Kdouglas89]

Update : I swapped out my clipped and bored 16g to a stock 16g and it made no difference in brake boosting. The stock came on a lot sooner, but did not hit as hard as my 16g. My 16g seems a lot laggier, but it hits all at once after the delay. I tried messing around with the tune in the cells it was using while brake boosting. Tried increasing timing to around 30, and also retarding timing to around 7 with my afr's being around 12-12.5, only able to build 2.5lbs at 2100rpm.

Starting to think it might be the cams / gears.

 

[SS Laser]

Update : I swapped out my clipped and bored 16g to a stock 16g and it made no difference in brake boosting. The stock came on a lot sooner, but did not hit as hard as my 16g. My 16g seems a lot laggier, but it hits all at once after the delay. I tried messing around with the tune in the cells it was using while brake boosting. Tried increasing timing to around 30, and also retarding timing to around 7 with my afr's being around 12-12.5, only able to build 2.5lbs at 2100rpm.

Starting to think it might be the cams / gears.

Yes^^^^^^^^^^^^^^^^^^^^^^^^^
I know is SUCKS to try it. But I bet it will work. And you can tell us for sure.

 

[TalonSpeed]

Anytime you shift the power band to the right (upper rpms) it will make it harder to stall a converter. You will need a higher stall speed, just like driving down the road boost hits at a higher rpm.

I had a 2.3 with hks 264 cams, stock 2g intake manifold, evo 3 ex manifold and turbo. I could spool that little turbo in no time using a PI billet TC. But power peaked at 6k then tanked.

I switched to a jmf street intake manifold, i had to dig a little deeper into the gas pedal, but still a quick stall up. Power picked up in top end

I then switched to CXracing ex manifold, kelford 272s (WAY larger than hks272s), HX40 6 blade with bep 55 AR housing. Top end power is great! transient boost is great on the highway due to small AR housing, but I cannot spool this turbo up easy at the line. I need a stall speed of 3500-4000rpm. The TC will stall that high, but the engine doesnt make enough low end torque to get there quickly. It takes time. Too much time for my taste. Brake boosting for a long time COOKS the transmission fluid. I have two coolers tho.

There is a solution. NITROUS!!

Just watch how this car leave on a 100 shot.

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vs

This one with no nitrous

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Most of the fast autos u see claiming "NO NITROUS" mean they are only spraying to flash the converter or up until a set boost in first gear. To me thats still using it but whatever.

 

[Kdouglas89]

It's irritating, because I know nitrous would solve my issues, but I 100% absolutely should not need nitrous to spool a slightly bigger and clipped 16g. I have decided that I will be saving my money and have a TC stalled higher. For the time being, I will keep my car off the track and enjoy it for awhile. I know "Bigdnno" will hate that answer, but the car is so fun just to drive around right now . My launch is to awful to keep pushing it on the track.

Kevin