C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

popping in exhaust

Old 08-13-2010, 10:05 AM
  #1  
kenv
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St. Jude Donor '10

Default popping in exhaust

I just got my Procharged `90 last month, & a problem it seems to have is when I jump on it, I hear popping in the exhaust. When I drive it normaly, it seems ok. I have to say, for all the stuff thats in this car (383, Trick Flow heads, ZZ9 cam etc.) I am not all that impressed with the performance. Mabey it needs a tune up after sitting for a few years. It is pretty cool though. Its the popping that has me bothered at the moment. Anyone know what this could be? This is my first FI car- Thanks, Ken
Old 08-13-2010, 01:46 PM
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mgroshong
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Is it tuned?
Old 08-13-2010, 03:30 PM
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Too lean ... need injectors, pump, tune and HELP ! LOL
Old 08-13-2010, 09:56 PM
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kenv
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Thanks for the replies. I have not had it tuned yet. I`m currently looking for someone around my area who is experienced in FI to look at it.
Old 08-14-2010, 05:00 AM
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I would suggest not driving it or at the very least not in boost till it is tuned. Very bad things can happen quicker then you think.
Old 08-14-2010, 10:41 AM
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KEN

GIVE GREG FROM BLOWERWORKS A CALL
HE KNOWS C4'S.


1 201.891.4690
Old 08-15-2010, 03:56 AM
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Coconut
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Originally Posted by kenv
Thanks for the replies. I have not had it tuned yet. I`m currently looking for someone around my area who is experienced in FI to look at it.
I don't know where you're at in FL, but I know there are experienced shops for Corvettes with DFI setups (great for boost) in Jacksonville, FL, Panama City, FL, & Mobile, AL (which is close to NW FL).
Old 08-15-2010, 10:07 AM
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Originally Posted by Coconut
I don't know where you're at in FL, but I know there are experienced shops for Corvettes with DFI setups (great for boost) in Jacksonville, FL, Panama City, FL, & Mobile, AL (which is close to NW FL).
realy? i called all around not to long ago and no one would tune a lt1. all they would offer is to dyno it to see curent HP.
Old 08-15-2010, 05:50 PM
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1. Upgrade stock fuel pump to walbro 340 255 liter/hr w/ racetronix hotwire wiring.

2. are you using the FMU (that comes in the procharger kit) or do you have bigger injectors and a tune? If you are using the FMU, ditch it for higher lb.hr injectors (60 lb/ hr). You will then need to tune

3. get a base tune and an ostrich from Greg @ blowerworks. I got one of his base tunes. I can vouch its pretty good (at least the lt1 tune I got).

4. It doesnt stop here. Download tunerpro RT software from the tunerpro.net website. Then use tunerpro.net (website) to download the appropriate definition file (for my '93 its $DA2) to be able to read/modify the base tune you got from Greg @ Blowerworks.

5. I recommend getting a wideband O2 sensor and installing it so you can see what AFR's you are running.

This is a subject in itself, but you can datalog the wideband info through the A/C pressure sensor, that way its referenced to RPM, MAP, TPS, etc.

Elsewise you can just keep an eye on the readout at WOT (more easier said than done) to ensure you are at the appropriate 12.0:1 AFR.

6. If you dont get a wideband O2 sensor, I recommend taking it to a dyno and tuning it using their wideband O2 sensor.

You will want to mess with the power enrichment tables. If its not dialed into 12.0:1 AFR, you may want to make some changes. To make the appropriate changes, there are 2 power enrichment tables you need to modify.

a. PE (power enrichment) % change to AFR vs. coolant temp
THis table has the greatest effect on your WOT AFR

b. PE % change to AFR vs. RPM. You can use this to modify WOT AFR, at specific RPM's, in case its leaning out at higher RPM.

c. You also may want to adjust the % throttle position to trigger PE (power enrichment) mode. Some people have told me that this should be lower (lower % throttle to trigger PE mode) with boost to prevent the car from ever being lean when going into boost (like going up a hill, under load).

7. Part throttle stuff, SHOULD be controlled by your O2 sensors. So you shouldnt have to worry too much about tuning VE tables (because Greg's base tunes already have done that).

8. Consider ditching the procharger intercooler (its just a flow restriction, decreases your max boost) and adding meth injection. It keeps intake temps cool.

9. Once you get the tune dialed in, you can get a chip burned (from greg) to replace the Ostrich (that plugs into your chip socket).


10. Beware of belt slip if you are using the procharger bracket. This is especially an issue with P600b prochargers with the low step up ratio (3.10:1) and small diameter pulleys. Greg makes a fix for this.

11. Happy boosting and shutting down punks (and the occasional streetbike).

Last edited by dizwiz24; 08-15-2010 at 05:53 PM.
Old 08-16-2010, 05:48 PM
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kenv
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St. Jude Donor '10

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Originally Posted by Coconut
I don't know where you're at in FL, but I know there are experienced shops for Corvettes with DFI setups (great for boost) in Jacksonville, FL, Panama City, FL, & Mobile, AL (which is close to NW FL).
Thanks, but the FI in my post is for forced induction. I live in Pa. Sorry for the confusion
Old 08-16-2010, 05:52 PM
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kenv
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St. Jude Donor '10

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Originally Posted by dizwiz24
1. Upgrade stock fuel pump to walbro 340 255 liter/hr w/ racetronix hotwire wiring.

2. are you using the FMU (that comes in the procharger kit) or do you have bigger injectors and a tune? If you are using the FMU, ditch it for higher lb.hr injectors (60 lb/ hr). You will then need to tune

3. get a base tune and an ostrich from Greg @ blowerworks. I got one of his base tunes. I can vouch its pretty good (at least the lt1 tune I got).

4. It doesnt stop here. Download tunerpro RT software from the tunerpro.net website. Then use tunerpro.net (website) to download the appropriate definition file (for my '93 its $DA2) to be able to read/modify the base tune you got from Greg @ Blowerworks.

5. I recommend getting a wideband O2 sensor and installing it so you can see what AFR's you are running.

This is a subject in itself, but you can datalog the wideband info through the A/C pressure sensor, that way its referenced to RPM, MAP, TPS, etc.

Elsewise you can just keep an eye on the readout at WOT (more easier said than done) to ensure you are at the appropriate 12.0:1 AFR.

6. If you dont get a wideband O2 sensor, I recommend taking it to a dyno and tuning it using their wideband O2 sensor.

You will want to mess with the power enrichment tables. If its not dialed into 12.0:1 AFR, you may want to make some changes. To make the appropriate changes, there are 2 power enrichment tables you need to modify.

a. PE (power enrichment) % change to AFR vs. coolant temp
THis table has the greatest effect on your WOT AFR

b. PE % change to AFR vs. RPM. You can use this to modify WOT AFR, at specific RPM's, in case its leaning out at higher RPM.

c. You also may want to adjust the % throttle position to trigger PE (power enrichment) mode. Some people have told me that this should be lower (lower % throttle to trigger PE mode) with boost to prevent the car from ever being lean when going into boost (like going up a hill, under load).

7. Part throttle stuff, SHOULD be controlled by your O2 sensors. So you shouldnt have to worry too much about tuning VE tables (because Greg's base tunes already have done that).

8. Consider ditching the procharger intercooler (its just a flow restriction, decreases your max boost) and adding meth injection. It keeps intake temps cool.

9. Once you get the tune dialed in, you can get a chip burned (from greg) to replace the Ostrich (that plugs into your chip socket).


10. Beware of belt slip if you are using the procharger bracket. This is especially an issue with P600b prochargers with the low step up ratio (3.10:1) and small diameter pulleys. Greg makes a fix for this.

11. Happy boosting and shutting down punks (and the occasional streetbike).
WOW! Thanks for the info. I`m not afraid to admit it, but this stuff you are talking about is WAY over my head. I guss I`m just a 60+ year old dumba$$ when it comes to this stuff I`ll have to have someone look at it when I get some coin. ( even though I`m not sure how it all works, just having it is still way cool)
Old 08-21-2010, 11:14 PM
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Coconut
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Default Accel

Originally Posted by Guitarguy
realy? i called all around not to long ago and no one would tune a lt1. all they would offer is to dyno it to see curent HP.
Contact Accel for the shops they recommend for installs of their DFI systems.

Those shops can usually help.
Old 08-21-2010, 11:15 PM
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Coconut
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Default Ok

Originally Posted by kenv
Thanks, but the FI in my post is for forced induction. I live in Pa. Sorry for the confusion
OK. Not a problem. Good luck!
Old 08-21-2010, 11:18 PM
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Coconut
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Default Wide-Band O2 Sensor


A wide-band O2 sensor is the only way to go when using forced induction.

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