cutting up under boost

[black97spyder]

Just got my 97 awd talon up and running yesterday and was driving today. If I get under boost too fast in like first gear, the car sputters and backfires then clears up if I keep my foot in it. If I roll into boost its fine until above 6k rpm then it misfires. This happens at stock boost on my 20g (10psi) or at 15psi.

Could it be a boost leak, even though the gauge doesnt wobble or move?

Or would it be spark or fuel related? Im not sure where to check first or if anyone else has had similar problems?

 

[Dsmkauai]

Ya the leak at the jpipe is common and always a pain to get sealed all the way. Make sure both surfaces are flat and use a gasket with rtv on both sides, should do the trick.

 

[2000mitsygt]

check wastegate do you have aftermarket boost gauge that tells you the pressure if so let us know what its set at because if the wastegate doesnt close you could be getting fuel cut off from high boost i couldnt get past 4500rpms and change the wastegate and boom good to go

 

[Ace_gst]

^^ what he said..I had hell with mine till I bought a new metal gasket and some black rtv from summit racing that v8 guys use for intake manifolds. It skins in 10 min and your ready to reassemble. Make sure bolts are not bottoming out and are in fact clamping the jpipe to turbo flange.

 

[black97spyder]

Thanks for all the help john! Wastegate I know is good because it has only 120ish miles on it. And the Wastegate flapper was ported by justin when he did the rebuild 120ish miles ago. I will try silicon on both sides of the gasket and hopefully that helps! I was worried the turbo would get too hot for the hi temp silicon or the right stuff gasket maker.

What kind of gasket should I use? A paper jpipe gasket or the metal exhaust style jpipe gasket? I have two spairs of each kind and dont want to have to mess with the jpipe again any time soon.

I will check one of the jpipe bolts to make sure its not bottoming out, the other side is straight through so i know it tightens down fine.

Would that major boost leak at the jpipe cause fuel cut from overboosting? My gauge shows a steady psi(set at 13-14psi) and will maybe drop 2-3 max psi if I let the auto shift too soon with my huge cams (sometimes ill let it shift at 3600 and drops to 2300ish rpm in the next gear, which is when it sometimes looses a psi or two)

thanks for all the helps guys! Im slowly getting the bugs worked out of this new setup

 

[Dsmkauai]

I would use the metal type I guess, I haven't had to mess with a jpipe in a while although my gvr4 has one. You could use the metal and some copper spray/hi temp rtv or the paper and hi temp rtv. Also think about how much harder your turbo has to work to keep up when you have boost leaks. Especially one right at the outlet of the compressor wheel (jpipe).

 

[black97spyder]

Yeah I know it would try to work the turbo to death with a big leak like that. But how much would it effect the a/f ratio or anything else tuning wise?

I will try the metal gasket and a thin bead of rtv on both sides of the gasket. Thanks for the suggestions bro!

 

[2000mitsygt]

did you check plugs and wires

 

[hotrodssnova]

Your a/f ratio is measured at the exhaust side from what your wb measures. If you have leaks on the intake side, tuning will be inconsistent at best. If you have leaks before your o2 sensor, your data to tune with will be false. Just some things to consider.