Help! Supercharger issues.
Thread Starter
6th Gear
Joined: Jun 2006
Posts: 6
Likes: 0
Help! Supercharger issues.
Hello all. New to the Forum. Hopefully somone can give some direction. I am running a Vortech on a lightly modded 93 and it has provided great all around street driveability and reliability for the past year or so. One major problem. At full throttle, the motor craps out at 4800rpm. It almost feels like the "fuel cut" I used to experience in my turbo cars. Played with the timing via the BTM and the more I back off timing, the worse it will run. Checked the rev limiter and its set for 6200. I am running the 10:1 FMU with the T rex pump. Is this a fuel related problem? Never had the car tuned (speed density). It pulls real strong to the 4500-4800, and then boggs out like a bucking bronco. It's getting really old having to granny shift every time full boost is just coming on. My buddy with a modded 03 Cobra loves it as he pulls further and further away with every shift... HELP!
Racer
Joined: Jul 2002
Posts: 313
Likes: 1
From: Dallas Tx
Originally Posted by blown93vette
Hello all. New to the Forum. Hopefully somone can give some direction. I am running a Vortech on a lightly modded 93 and it has provided great all around street driveability and reliability for the past year or so. One major problem. At full throttle, the motor craps out at 4800rpm. It almost feels like the "fuel cut" I used to experience in my turbo cars. Played with the timing via the BTM and the more I back off timing, the worse it will run. Checked the rev limiter and its set for 6200. I am running the 10:1 FMU with the T rex pump. Is this a fuel related problem? Never had the car tuned (speed density). It pulls real strong to the 4500-4800, and then boggs out like a bucking bronco. It's getting really old having to granny shift every time full boost is just coming on. My buddy with a modded 03 Cobra loves it as he pulls further and further away with every shift... HELP!
Have you done any valve train work on your car? If not, you shouldn't be reving it up to 6200 RPMs.
What about putting it on the dyno and checking the AFR?
Thread Starter
6th Gear
Joined: Jun 2006
Posts: 6
Likes: 0
No valve train work yet- would shift at 5500 if I could... No data software yet either. What is the recommended setup? I guess a dyno tune is in order. I'm in the Chicagoland area. Any reputable shops anyone could recommend?
Also, I've heard of increasing injector size to 38 or 42 and going with a smaller FMU or getting rid of the FMU all together. I don't want to hurt driveability, as the car is a daily driver.
PS. My friends and I are arguing about temp sensor location.. Should it go right after the aircleaner on the inlet tube or in the bung on the blower discharge right before the throttle body?? I've tried both and there was no change in performance or driveability.
Also, I've heard of increasing injector size to 38 or 42 and going with a smaller FMU or getting rid of the FMU all together. I don't want to hurt driveability, as the car is a daily driver.
PS. My friends and I are arguing about temp sensor location.. Should it go right after the aircleaner on the inlet tube or in the bung on the blower discharge right before the throttle body?? I've tried both and there was no change in performance or driveability.
Racer
Joined: Jul 2002
Posts: 313
Likes: 1
From: Dallas Tx
Originally Posted by blown93vette
No valve train work yet- would shift at 5500 if I could... No data software yet either. What is the recommended setup? I guess a dyno tune is in order. I'm in the Chicagoland area. Any reputable shops anyone could recommend?
Also, I've heard of increasing injector size to 38 or 42 and going with a smaller FMU or getting rid of the FMU all together. I don't want to hurt driveability, as the car is a daily driver.
PS. My friends and I are arguing about temp sensor location.. Should it go right after the aircleaner on the inlet tube or in the bung on the blower discharge right before the throttle body?? I've tried both and there was no change in performance or driveability.
Also, I've heard of increasing injector size to 38 or 42 and going with a smaller FMU or getting rid of the FMU all together. I don't want to hurt driveability, as the car is a daily driver.
PS. My friends and I are arguing about temp sensor location.. Should it go right after the aircleaner on the inlet tube or in the bung on the blower discharge right before the throttle body?? I've tried both and there was no change in performance or driveability.
The general concensus is to get rid of the inline fuel pump and the FMU and upgrade to a larger intake pump and 42# injectors.
I recommend lucas (disc) type injectors as they have faster opening times. BUt either way, you shouldn't have a problem with idle or driveability with 42# injectors (it is more once you get up to 60#+ inj.).
The High RPMs on a stock LT1 valve train can be devistating. I recommend lowering your RPM (although not causing your problem).
I don't know anyone in the chicagoland area with experience in vettes (try your regional forum for that information). Sorry.
TTS datamaster and a cable from www.akmcables.com is recommended. You get 20 free datalogs with the software, but the cable is about $60. Well worth it. Definetly get it tuned on a dyno.
Also, drop me a line and let me know how it works out. GL!
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
My "guess" is you are seeing knock retard and it is pulling the timing... You really need to get a data logging program to see what is really happening, I would halt any full throttle runs until you see what is really happening, the stock pistons will not take alot of abuse...
also another thing to check is your plugs, they should be at least one step colder and gapped around .035 , it could be blowing out the spark.
I have relocated my IAT to the amient air, but when i had mine setup in earlier setups, it would richen up the mixture... as the intake air increased, do you have a boost guage? Are you pushing 6 or 8 pounds of boost?
Again it keeps coming back to you need either wideband O2 sensor or again a data log program to see what your O2's are reading...
Hope this helps,
MO
also another thing to check is your plugs, they should be at least one step colder and gapped around .035 , it could be blowing out the spark.
I have relocated my IAT to the amient air, but when i had mine setup in earlier setups, it would richen up the mixture... as the intake air increased, do you have a boost guage? Are you pushing 6 or 8 pounds of boost?
Again it keeps coming back to you need either wideband O2 sensor or again a data log program to see what your O2's are reading...
Hope this helps,
MO
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by blown93vette
Hello all. New to the Forum. Hopefully somone can give some direction. I am running a Vortech on a lightly modded 93 and it has provided great all around street driveability and reliability for the past year or so. One major problem. At full throttle, the motor craps out at 4800rpm. It almost feels like the "fuel cut" I used to experience in my turbo cars. Played with the timing via the BTM and the more I back off timing, the worse it will run. Checked the rev limiter and its set for 6200. I am running the 10:1 FMU with the T rex pump. Is this a fuel related problem? Never had the car tuned (speed density). It pulls real strong to the 4500-4800, and then boggs out like a bucking bronco. It's getting really old having to granny shift every time full boost is just coming on. My buddy with a modded 03 Cobra loves it as he pulls further and further away with every shift... HELP!
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Drifting
Joined: Aug 2002
Posts: 1,475
Likes: 0
From: Speedo Indiana
Originally Posted by blown93vette
No valve train work yet- would shift at 5500 if I could... No data software yet either. What is the recommended setup? I guess a dyno tune is in order. I'm in the Chicagoland area. Any reputable shops anyone could recommend?
Also, I've heard of increasing injector size to 38 or 42 and going with a smaller FMU or getting rid of the FMU all together. I don't want to hurt driveability, as the car is a daily driver.
PS. My friends and I are arguing about temp sensor location.. Should it go right after the aircleaner on the inlet tube or in the bung on the blower discharge right before the throttle body?? I've tried both and there was no change in performance or driveability.
Also, I've heard of increasing injector size to 38 or 42 and going with a smaller FMU or getting rid of the FMU all together. I don't want to hurt driveability, as the car is a daily driver.
PS. My friends and I are arguing about temp sensor location.. Should it go right after the aircleaner on the inlet tube or in the bung on the blower discharge right before the throttle body?? I've tried both and there was no change in performance or driveability.
http://www.flp2win.com
Thread Starter
6th Gear
Joined: Jun 2006
Posts: 6
Likes: 0
TJWONG- I'm sure the inline pump is working as it's pretty loud.
I've used 255Lph in tank pumps on my old turbo cars. I think the T rex is a 255LPH and the stock in-tank is 190? What in tank pump are you big power guys using as I am thinking of going bigger with my 93 daily driver? (Don't want to change the pump twice).
I'm not sold on the Kenne Bell boost a pump, as my buddy with a highly modded 03 Cobra has burned up two pumps with it. Although the trick of hard wiring the pump to the battery worked well on the turbo buicks..
????
I've used 255Lph in tank pumps on my old turbo cars. I think the T rex is a 255LPH and the stock in-tank is 190? What in tank pump are you big power guys using as I am thinking of going bigger with my 93 daily driver? (Don't want to change the pump twice).
I'm not sold on the Kenne Bell boost a pump, as my buddy with a highly modded 03 Cobra has burned up two pumps with it. Although the trick of hard wiring the pump to the battery worked well on the turbo buicks..
????
Thread Starter
6th Gear
Joined: Jun 2006
Posts: 6
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TONYDEE64- Thanks for the info. I actually live in Naperville about 3 miles from FLP. I guess I'll give them a call. Most of my LS1 and Cobra Mustang buddies send there stuff up north in Bloomingdale IL, but no one has any experience with pre 94 non mass air stuff... What's the best bang for the buck tuning system out there for me? Just a wideband and a meter? Who reprograms the ECU's?
Drifting
Joined: Feb 2004
Posts: 1,277
Likes: 1
From: Santa Maria CA
a LM1 Innovative A/F ratio is getting pretty inexpensive now-a-days. You can monitor the A/F constantly after mods and adjust the FP when needed to help compensate for whats been done. If you tune its more important by far,but if you will never tune then its probobly not a big "NEED".