legacycentral bbs

alright so i finally got insurance on my ru, and am experiencing turbo lag like crazy. I have a TMIC, cars only running 6lbs boost (LOL) and today i got beaten by a honda civic, because of how hard it lags. Any guesses as to why its lagging ? I have full 3", intake, runs mint, but it lags like a mofo

Exhaust leak? You do have 6 gaskets between your heads and turbo.

+1 on e-leak.
I'd also check for boost leaks on the TMIC set-up...
If the turbo sounds like a jet's turbine you probably have a boost leak.

Hmmmmmmm exhaust leak where at? I did myexhaust and there may be a few pinhole leaks but nothing major. As for boost leaks I will have to look...turnosounds quite loud...I'll have to check it out

one more thing...my boost guage is connected off intake runner...seems like my boost goes up with throttle position not rpm...sound right?o

Like I said, there are 6 gaskets between your motor and turbo. The crossover pipe gaskets usually aren't suspects, but your manifold to head, lower uppipe, and uppipe to turbo gaskets are all suspect. Get under there and figure it out.



As far as the boost with throttle, that's how they work. Your turbo's response is not totally dependent on rpm. Throttle position plays a huge part as well, as a turbo's response is dependent on load, which is a function of rpm and throttle position. Below 4k rpm, I can regulate boost with the throttle, since I am varying how much load is on the engine.

93forestpearl, thanks for the help, are the gaskets fairly easy to replace ? How can i tell if they're leaking or not ?

If you have an exhaust leak before the turbo you may see soot around the joint - a leak after the turbo may net you a hp or two...

Not sure how cold it is in your area but if it is cold enough to see the exhaust (steam/fog) then you could start the car up & look under it for a leak.

If the turbo sounds louder than normal I'd think you are leaking boost - double check your connectors.

another way to check if it's cold is to(better up on lift) have someone hold a rag to plug your tailpipe to create a little pressure and then check where all your gaskets are, you could also have a crack in one of your pre turbo pipes. oh yeah, and changing those gaskets, it can be a bitch, buy oem ones. if you do take it all apart at least youll know where the problem lies, be prepared to break a bolt or two.


did this just recently start happening or was it after you started playing with things?

RJ93SS wrote:buy oem ones.

Quoted for necessity. Also, NA exhaust manifold gaskets ≠ turbo gaskets. The turbo gaskets are multi-layer steel, vs the fiber material with a steel backing that the NA gaskets are, which will burn up in short order.

OEM gaskets are worth what you pay for them, generally.

If you seafoam your engine you'll get white smoke through your exhaust. Leaks can't hide from it.

Hmm, it didnt recently start doing it, but i just recently started to notice it, seems like it lags way too much. My turbo sounds like a jet engine, I can hear it crazy loud, like way too loud. I will check for boost leaks tonight.. now i gotta go to the dentist :|:|

My $'s on a boost leak. The turbo's aren't that loud on these cars even desnorkled and MUG'd. If it sounds REALLY cool , then its probably a boost leak, but that should be easy to find if you don't have a TMIC. Just check the tube coming off the turbo going to the throttle body.

If you have a boost guage why not disconnect the wastegate actuator and see if the boost builds fast then? Watch for spikes!

ciper wrote:If you have a boost guage why not disconnect the wastegate actuator and see if the boost builds fast then? Watch for spikes!

Can you explain this a bit better ?

If you disconnect the "plunger" that opens the wastegate it should stay closed all the time. If boost still builds slowly then it confirms some type of leak.

Just be careful because you could/will easily overboost like this and could destroy your engine if you aren't paying attention.

Alright ciper, i'll try that.

few notes. Lots of black shit built up ON THE TURBO, right by the turbo OUTLET. No soot near gasket areas on turbo though.. ideas ?

Something is hugely wrong for sure though, as I just ran an 18.9 with my GTAC :|:|

ALSO ! According to my gauge, boost builds very quickly, but the car itself feels like its lagging.. maybe not turbo related ? Just did plugs/wires, no change.

I floor my car, I hear the turbo spooling like a mofo and shhhhhhhhhhh, and the boost builds now to 8psi ish (hooked up stock boost sylinoid). I have an autometer ulta lite boost gauge hooked up the the 4th runnner if it helps ....

boost leak.

Got a wideband? Probably dumping rich as hell too and following on it's face. Like was said, boost leak most likely at the intake side. If it was at the exhaust side boost will build SLOWLY.

If it was a boost leak though would it still show boost building quickly off #1 intake runner ?

What do you mean wideband... 02 sensor ? I know nothing when it comes to computers/sensors

One more thing.. could the wastegate be being held open too long ?

Its so hard for me to diagnose, but it almost seems like its not a boost leak. The main thing that makes me thing this is that #1 intake runner is getting 8lbs boost consistantly, so that means that theoretically 8lbs boost is coming out the turbo, through the y pipe, through the intercooler, through the Tb, and into the intake manifold correct ?

I heard that the coil be be dogging out...

A small boost leak would still allow your turbo to make the factory boost level. What people are trying to get at is if you have a small leak, the car will be running overly rich, killing some power that you would otherwise normally make. Have someone watch you from behind and see if they notice any black smoke from exhaust. That would indicative of an over-rich condition.

Cars running like a POS... bahhhhhhhhhhh this is making me mad.

Hm... and my current symtoms.

Car builds boost quickly, cars rpms rise quickly, I can hear it runnin really funny out the exhaust (popping,spitting, dying out). Im sure my y-pipe has no boost leaks now, and the gaskets all look pretty good. Not sure about my other two fittings (IC to TB, and TO to IC), but they look fine and have no visible cracks. I can still hear my turbo fairly loud, but that might just be because of my intake and exhaust.

Im in the process of redoing my intake right now, so my cone filter is coming right off my MAF. Will this be alright ? I used to have a 90* bend right before my MAF, but i heard that this causes turbulence, so im running it right off my MAF now.

Im starting to think it might be a vacuum leak. Whatever it is, its significant, and the cars running like crap... well let me rephrase that. The car starts, and runs amazingly, starts RIGHT AWAY, split second after i turn the key its on, doesnt hesitate at all, even when its dead cold. My car seems to run worse when its cold then when its warm, power wise. My temperature is staying mid range, and oil pressure is keeping good. I remember seeing a vacuum diagram here somewhere... can anyone direct me to it ? THanks