Mod question
Thread Starter
Instructor
Joined: Nov 2004
Posts: 190
Likes: 0
From: Greenville Ohio
St. Jude Donor '05
Mod question
I have some questions for the Vette experts out there.
The car: 86L automatic coupe
The Mods:
180 thermostat
TB bypass
52mm TB
new Aluminum radiator
Raptor transmission
manual fan switch
removed screens from MAF
Ported stock plenum
SLP runners
Accel manifold
Ram air system
Air pump eliminator
LT headers
No cats
Magnaflow exhaust
MSD distributor
Now my Question:
At what point do I need to upgrade fuel injectors and fuel pump?
How many gph do you suggest?
-Also I am in the process of trying to figure out a cam/valves/lifters combo to maximize low end torque and accelleration to approx. 65 mph for autocross purposes- any suggestions?
Thanks Roger
The car: 86L automatic coupe
The Mods:
180 thermostat
TB bypass
52mm TB
new Aluminum radiator
Raptor transmission
manual fan switch
removed screens from MAF
Ported stock plenum
SLP runners
Accel manifold
Ram air system
Air pump eliminator
LT headers
No cats
Magnaflow exhaust
MSD distributor
Now my Question:
At what point do I need to upgrade fuel injectors and fuel pump?
How many gph do you suggest?
-Also I am in the process of trying to figure out a cam/valves/lifters combo to maximize low end torque and accelleration to approx. 65 mph for autocross purposes- any suggestions?
Thanks Roger
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Probably never. With your present and planned mods, the pump, especially, and the injectors will remain adequate. When it comes to fuel, more isn't better. You can check your BLMs and better yet, your A/F ratio and up the pressure, if necessary, with an adjustable fuel pressure regulator.
RACE ON!!!
RACE ON!!!
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
If you're wanting 0 to 65 MPH grunt you're gonna want a set of heads with a small intake runner and a very mild cam. For an intake, either leave it stock or go with the super ram.
Most cams drastically reduce low end torque, which is what it sounds like you're wanting to keep. Certainly do your research on this one first.
As for the fuel pump, you're fine with the stocker and the stock injectors for a long time to come yet.
Most cams drastically reduce low end torque, which is what it sounds like you're wanting to keep. Certainly do your research on this one first.
As for the fuel pump, you're fine with the stocker and the stock injectors for a long time to come yet.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Your stock injectors are good to about 350chp with an AFPR to bump fuel pressure for more fuel at WOT.
With a new cam it's ok to increase lift but hold overlap to a minimum buy not going too big on duration (<225@.050") nor too small on LSA (>=112deg).
But first consider your useful RPM range during auto-cross events. For example you launch once and thereafter what RPM band are you in??? For example, at 27mph in 1st gear (A4 with 2.59 gears) my tach is at 3,000rpm; would you ever drop below that speed on the circuit??
I think that building mid to upper range (say 3,000-6,000rpm) torque would be most beneficial for auto-cross. Once you have your target RPM range, take a look at some Comp. Cams cams designed for that range to get an idea of typical cam specs of interest.
With a new cam it's ok to increase lift but hold overlap to a minimum buy not going too big on duration (<225@.050") nor too small on LSA (>=112deg).
But first consider your useful RPM range during auto-cross events. For example you launch once and thereafter what RPM band are you in??? For example, at 27mph in 1st gear (A4 with 2.59 gears) my tach is at 3,000rpm; would you ever drop below that speed on the circuit??
I think that building mid to upper range (say 3,000-6,000rpm) torque would be most beneficial for auto-cross. Once you have your target RPM range, take a look at some Comp. Cams cams designed for that range to get an idea of typical cam specs of interest.
