DIY PROM Do It Yourself PROM chip burning help. No PROM begging. No PROMs for sale. No commercial exchange. Not a referral service.

No power Until 4500 RPM +

Thread Tools
 
Search this Thread
 
Old Apr 20, 2003 | 02:50 AM
  #1  
Chris Etemadi's Avatar
Thread Starter
Senior Member
 
Joined: Oct 1999
Posts: 548
Likes: 0
From: Dallas, Texas
Car: 1991 Z28
Engine: 5.3 Gen III SBC
Transmission: 4L80E NTC 258mm Stall
Axle/Gears: Trick Chassis 9" 3.50 S-Strac
No power Until 4500 RPM +

I got her back together. I am running the stock chip (I know) I have all the software to burn my own chips. I dont think i should start until I get new injectors I think my factory ones now 175K miles on them, are really inconsistent. All my friends are trying to get my to swap over to a carb. I dont want to do that because its kind of the "easy way out" since my car was equipped with fuel injection factory i want to keep it. They are convinced I cant go as fast with EFI as I can carburated.
Well to the problem, Im not getting near the torque I should it seems. I know going to the LT1 intake would reduce my low end grunt, and move it to mid range. but its like the car comes alive more at 4500, as you can see my listening to the motor and watching the tach after 4500 it is running alot stronger.
I have a 355 with 6" rods about 10.5:1 comp. a CC305 cam,LT1 intake, ported L98's, stock injectors I know running the factory chip is hurting me some but Im hoping I have alot more in it than what I am seeing now. What exactly would cause the motor to just waken up like this? Sorry for the length, but I would rather stay Injected and show up all my friends. Thanks for your help in advance,
Chris
Reply
Old Apr 20, 2003 | 09:30 AM
  #2  
va454ss's Avatar
Senior Member
iTrader: (1)
 
Joined: Feb 2003
Posts: 785
Likes: 0
Car: 90 454SS
Engine: 454 TBI
Transmission: TH400
Sounds like you need to increase your initial timing.
Reply
Old Apr 20, 2003 | 09:55 AM
  #3  
Grim Reaper's Avatar
TGO Supporter
 
Joined: Jul 1999
Posts: 10,907
Likes: 5
From: The Bone Yard
Car: Death Mobile
Engine: 666 c.i.
You hit the nail on the head, your eprom is off. Yes, SD can actually run with a number of mods and "appear" to run reasonably well. But once you tune the eprom properly, you will quickly find that it is far from optimal.

Yes, your intake and cam promote higher rpms HP while sacrificing low-end grunt that you experienced with TPI. But, the stock TPI bin adds far too much fuel at lower RPMs while severely dropping past 4,000 rpm.

I suspect you are overly rich at lower rpms, and possibly lean at higher rpm.

Do the chip.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
angel2794
Theoretical and Street Racing
25
Mar 7, 2026 01:08 PM
theshackle
Tech / General Engine
4
Sep 17, 2020 08:26 AM
sailtexas186548
Problems / Help / Suggestions / Comments
2
Aug 24, 2015 10:11 PM
mdtoren
TPI
12
Aug 23, 2015 12:52 PM
mdtoren
Tech / General Engine
0
Aug 16, 2015 05:45 PM




All times are GMT -5. The time now is 04:07 PM.