Boost Problems

[IvanS13]

SR20DET RedtopHKS Type-S FMICHKS SSQVBlitz 3" DownpipeBlitz Nur Spec-RTurbo XS MBCWalbro Fuel Pump

So I raised the boost from 12 to 14psi just to see what kind of a difference it would make, and something weird happened. When the car would hit full boost @ 14psi, the car would studder very hard, made a really fast "boo boo boo boo boo boo" type sound. Seemed almost like it was hitting rev limiter... even if I'd hit full boost around 4000RPM's, the car felt like it was being cut off some how. BTW, their would be no problems at WOT until it hit 14psi, everything before that felt alright, pulled like normal, ect. Any thoughts?

Cliff notes: So i'd hit it, watch the boost and RPM's go up, everything is pulling like normal, and as soon as the boost gauge hit 14, the car begins studdering VERY hard, fealt like rev limiter. even though i would be around 3500RPM's.

BTW, I have an exhaust leak where my downpipe connects with the turbo. It's held on by one nut instead of three... gotta go fix that soon.

O yea, I am probably gonna go set it back to 12psi tomorrow, Iit was running perfectly normal at that pound setting. I was just wondering if anything broke

[ItzGenX]

Sounds like the problem I was having at 5psi (yeah I could barely hit 7 until I drove around more). My problem was that my spark gaps were too large to "make the jump" at certain boost settings. Either upgrade ignition system or lower your gap and see what it does. Also, it COULD be possibly running lean or maf is maxing out, so don't rule those out of the question.

[NS180]

make shue your timing is set right your plugs are good and the stock turbo t25 is not good ran at 14 pounds that is past it limit. alot of ppl say it can do it but I havent seen one run 14 pounds consitantly and last for over a monththe compressor is not capable of flowing that much air (that info is from other sources not my knowledge)

[BuudWeizErr]

What fuel pump?

How is your fuel filter?

[RobDET]

sounds like feul cut due to too mutch air through the MAF to me. See what happens at 12 again. If it's fine then i'll bet that's what it is.

[IvanS13]

Um... I am using a Walbro Fuel Pump. I got a brand new fuel filter (not the Z32 one) when the car was swapped, and the timing was set to spec. I am gonna turn it down today to 12psi and post up what happened... thanks for your help!

I doubt it would be the spark plugs because the car did not have the problem between 6-13psi, I ran different boost settings and it seemed alright. The problem arrised when I saw the boost gauge hit 14psi.

[IvanS13]

OK... I set the boost pressure back down to 12psi and no more bucking or problems once it hits full boost. I guess it was the MAF's being overrun?

Thanks guys!

[Movingviolation240]

what's your plug gap at? You might want to gap them down to like 032.

But it sounds like boost cut to me

Paul

[IvanS13]

what's your plug gap at? You might want to gap them down to like 032.

What should the (optimum) gap be on an SR20DET?

[Movingviolation240]

--------------------------------------------------------------------------------Originally posted by Movingviolation240 what's your plug gap at? You might want to gap them down to like 032.--------------------------------------------------------------------------------

32 as opposed to the 45 NGK ships them to you at....

[2k1MaxGLE]

SR20DET RedtopHKS Type-S FMICHKS SSQVBlitz 3" DownpipeBlitz Nur Spec-RTurbo XS MBCWalbro Fuel Pump

So I raised the boost from 12 to 14psi just to see what kind of a difference it would make, and something weird happened. When the car would hit full boost @ 14psi, the car would studder very hard, made a really fast "boo boo boo boo boo boo" type sound. Seemed almost like it was hitting rev limiter... even if I'd hit full boost around 4000RPM's, the car felt like it was being cut off some how. BTW, their would be no problems at WOT until it hit 14psi, everything before that felt alright, pulled like normal, ect. Any thoughts?

Cliff notes: So i'd hit it, watch the boost and RPM's go up, everything is pulling like normal, and as soon as the boost gauge hit 14, the car begins studdering VERY hard, fealt like rev limiter. even though i would be around 3500RPM's.

BTW, I have an exhaust leak where my downpipe connects with the turbo. It's held on by one nut instead of three... gotta go fix that soon.

O yea, I am probably gonna go set it back to 12psi tomorrow, Iit was running perfectly normal at that pound setting. I was just wondering if anything broke

Im having the EXACT same thing going on with mine....except my setup is as follows:

SR20DET RedtopTop Mount GT28RTial 38mm WastegateZ32 MAF800cc injectorsCustom FMICHKS SSQVCustom 3" ExhaustWalbro Fuel Pump

The Apexi AVCR is set at 17psi and everything has been tuned for this pressure but its doing the exact same thing yours is doing at around 15-16 psi...it sounds like its hitting a rev limiter almost....

[peters14gc]

Im having the EXACT same thing going on with mine....except my setup is as follows:

SR20DET RedtopTop Mount GT28RTial 38mm WastegateZ32 MAF800cc injectorsCustom FMICHKS SSQVCustom 3" ExhaustWalbro Fuel Pump

The Apexi AVCR is set at 17psi and everything has been tuned for this pressure but its doing the exact same thing yours is doing at around 15-16 psi...it sounds like its hitting a rev limiter almost....

it might need to be retuned to handle the airflow since you are running z32 maf.

[peters14gc]

SR20DET RedtopHKS Type-S FMICHKS SSQVBlitz 3" DownpipeBlitz Nur Spec-RTurbo XS MBCWalbro Fuel Pump

So I raised the boost from 12 to 14psi just to see what kind of a difference it would make, and something weird happened. When the car would hit full boost @ 14psi, the car would studder very hard, made a really fast "boo boo boo boo boo boo" type sound. Seemed almost like it was hitting rev limiter... even if I'd hit full boost around 4000RPM's, the car felt like it was being cut off some how. BTW, their would be no problems at WOT until it hit 14psi, everything before that felt alright, pulled like normal, ect. Any thoughts?

Cliff notes: So i'd hit it, watch the boost and RPM's go up, everything is pulling like normal, and as soon as the boost gauge hit 14, the car begins studdering VERY hard, fealt like rev limiter. even though i would be around 3500RPM's.

BTW, I have an exhaust leak where my downpipe connects with the turbo. It's held on by one nut instead of three... gotta go fix that soon.

O yea, I am probably gonna go set it back to 12psi tomorrow, Iit was running perfectly normal at that pound setting. I was just wondering if anything broke

get the downpipe flange fixed asap.

[black240sx96]

ok so i did a search and this is my same exact problem except that im running stock boost (5-7 psi) and once i hit the full boost i get the same sounds like backfiring and hitting rev limiter and what not...and everything is stock except for the walbro fuel pump and a z32 fuel filter and i had my timing down by a shop since i dont have a timing light...any suggestions ??

[IanS]

ok so i did a search and this is my same exact problem except that im running stock boost (5-7 psi) and once i hit the full boost i get the same sounds like backfiring and hitting rev limiter and what not...and everything is stock except for the walbro fuel pump and a z32 fuel filter and i had my timing down by a shop since i dont have a timing light...any suggestions ??

Check your plug gap.

Check your coil packs for cracking.

[black240sx96]

Check your plug gap.

Check your coil packs for cracking.

my plugs are gapped at .028 and my coil packs dont have no cracks...its an odd thing too because sometimes the idle will drop to about 300 rpms and go back to 750 like it just skipped a heart beat or something...and its quick too...

[IanS]

my plugs are gapped at .028 and my coil packs dont have no cracks...its an odd thing too because sometimes the idle will drop to about 300 rpms and go back to 750 like it just skipped a heart beat or something...and its quick too...

Check your fuel pressure, check your base electrical timing, and check for any codes in the ECU.

[burntricer]

BOV opening too soon?

[black240sx96]

Check your fuel pressure, check your base electrical timing, and check for any codes in the ECU.

what do you mean base electrical timing ??? and im not getting a check engine light so how do i check for codes in the ecu ???

[black240sx96]

BOV opening too soon?

nope...i have it set on hard and it only opens up when i let off at atleast 3 psi of boost...

[IanS]

what do you mean base electrical timing ??? and im not getting a check engine light so how do i check for codes in the ecu ???

The Cam angle sensor needs to be set to base timing of 15 degrees before TDC, and there is a special procedure for doing so.

Many times when SR swaps are performed, the wire for the CEL is not connected. You will need to pull your ECU and set it to diagnostic mode.

[black240sx96]

The Cam angle sensor needs to be set to base timing of 15 degrees before TDC, and there is a special procedure for doing so.

Many times when SR swaps are performed, the wire for the CEL is not connected. You will need to pull your ECU and set it to diagnostic mode.

ok...i will try that....but heres were it gets really weird....i had a shop do my timing because i dont have anything to do it myself...heres the weird part...when the put the timing right on it will idle great but once i give it more that 15% throttle it brakes up and if i go WOT it will spit backfire sputter pop and just rock the crap out of the car...then i had the look at it again and they had it so it would idle but drop rpms to about 300-400 then pick back up do this every so often but when i step on it it would go and as long as i dont hit full boost it run pretty good....not 100% but it will run as an sr should for the monst part...

[97koukile]

any input i have the same problem