Turbo Lag

[Neez]

Hey guys, ive read on a few forums about people saying that the turbo lag is almost very un-noticable. Ever since ive installed my boost gauge, i noticed that ive got very ungodly bad turbo lag. During a 2nd gear pull last night with with Stock S-J-Mid pipe, with everthing after the midpipe disconnected i noticed that my turbo spooled about the same as it did befor wit the exhaust all hooked up. Personally i thouht it might cut it down a little, but i did notice that in a 2nd gear pull from 1000 RPM, my boost gauge hits 0, then im waiting and waiting and it barely gets to 2 psi by about 2500-2800 rpm, then peaks at about 7 psi inbetweeen 3200-3500, is this normal or do you think that i've got some sort of vaccume leak? It just seems really odd that a small turbo like the t25 would take so long to spool up where as my brothers stock SRT-4 turbo is fully spooled to 18psi by about 2300-2500 rpm.. Feedback please, no flaming..

If it isnt correct by spooling so slow give me some ideas on how to spool it up quicker.

Thanks

 

[jamesk]

i do not think it is a vacuum leak, i think it is a boost leak. check the intercooler piping, bov or wastegate. it sounds like it is leaking anywhere before the throttle body. do you have the stock plastic piping? those tend to leak.

 

[Neez]

yes i have plastic stock piping, i knwo my reading when in vac is normal.. around 18-22 vac depending on weather i run my a/c or not, so i dont have a vaccume leak, it just seems to take really really long to built boost, and i know that with my aem intake you can REALLY hear boost, not sure if its normal either cause i cant compare to anyone with a turbo car with a cai.. hmm, i guess il have to check those out wen i put my dp on this week

 

[jamesk]

yea deff. your boost pipes. sounds like the turbo makes boost fine, just not getting into the engine.

 

[Matrix]

Well, although it could be a boost leak in your intake pipes, it also could be an exhaust leak before your turbo. I've currently got an exhaust leak right where the exhaust manifold bolts up to the head, and it's causing noticeable boost lag.

You might want to look into that possibility. Good luck!

 

[Neez]

alright.. well i do indeed know that i have an exhaust leak on my S-pipe, which is why im currently looking for a used c/s S-pipe only because ive got a 2.5" Jpipe already without cats that should be here monday. so thats why im wondering

 

[Matrix]

alright.. well i do indeed know that i have an exhaust leak on my S-pipe, which is why im currently looking for a used c/s S-pipe only because ive got a 2.5" Jpipe already without cats that should be here monday. so thats why im wondering

A leak at the S-pipe won't really affect how much boost your engine gets. The only things that will affect how much boost you get are either a leak in your intake pipes or an exhaust leak at the exhaust manifold between the head and the turbo.

 

[Lil Freek]

Also make sure the VCTS flaps are opening properly..

When the ones closest to the Head are closed, your car will not make boost until very late.

 

[Neez]

im not sure if u guys are onto what i mean though.. like some of you are.. but what im trying to say is, im getting normal stock boost numbers, 6-7 psi max, but it just takes for fricken ever to get there

 

[jamesk]

listen, just because the turbo will spool up to the correct psi, does NOT mean you have no boost leak. the turbo will spin as much as possible until the wastegate tells it not too. a boost leak will make the turbo spin longer because it would take a longer time for it to build pressure. so a small boost leak, and i mean small, will make the turbo build the same amount of boost in a longer time period.

the mazdaspeed protege does not come with a t25 turbo, it comes with a
gt25 turbocharger. it is the same thing as the t25, but ball bearing. a t25 is a small enough turbo as it is to spool fast, but the gt25 spins even faster.

it should reach 6 psi with not evening noticing its building up boost. if you notice it, then you probably have a boost leak

an exhaust leak would be heard and would be alot worse. and i am assuming the manifold is bolted up right as well as the egr tube.

 

[Neez]

ohh k yeah now it all is kind of making sense. im gona run out and check all of the clamps on my piping. Its not so much as though i can feel it (i mean yeah i can feel it but it isnt that noticable because its only 6 psi) but watching the boost gauge, and from what ive read the turbo should be spooling ALOT quicker than it does, so im gona run out and check some of the listed problems: Intake pipes, manifold leaks, and might even check the VTCS.

 

[low_psi]

Why are you going WOT in 2nd gear at 1000rpms? The engine is bogging horribly.

 

[03.5MSP]

Why are you going WOT in 2nd gear at 1000rpms? The engine is bogging horribly.

(iagree)

 

[XoX1de]

here's a clip with t3/t4 turbo on my 626. **** it lags with .63 a/r, i have 2.5full exhaust, no cat...

http://ca.youtube.com/watch?v=6Pn5RShrOLw

 

[low_psi]

Cool, a completely unrelated video.

 

[Knox Joe]

You need to use the small pedal on the right to fix your problem.

It probably is your driving style from what it sounds like.

 

[nvmsp]

2nd gear pull should be started just over 3K rpm's which is 30-34 mph.

 

[XoX1de]

the transmission is modified atx i only have 4 gear, the gear ratio is wide.

 

[nvmsp]

the transmission is modified atx i only have 4 gear, the gear ratio is wide.

no I was talking to the person who made this thread with the msp.

I didn't watch your vid yet of your car. Is it fast at all, curious?

 

[jamesk]

xox1de - you said your car became extrememly rich from 3500 to 4000 rpms because of maxing out your injectors? is that what happens if you max them out? cause that happens to me sometimes too.