Quick Tuning Question
Thread Starter
Intermediate
Joined: Jul 2006
Posts: 38
Likes: 1
From: New Jersey
Quick Tuning Question
Hey everyone, I read the loong long post on timing.
I have the Gm Perf. Crate ZZ502 Big Block, with the stock Holley Street Avenger carb, 870 cfm.
I put a scoop on there, for sorta like a Ram Air effect. But she hasnt run right for a while now, and Im getting a bit frustrated.
I checked my timing, I set it back 8'c1 BTDC @ 800 rpm; 36'c1 total @ 5000 rpm.
Set my Vac secondary spring back to stock purple, set the Carb to idle mixture stock setting
and checked my bowls for proper level, fuel pressure is good at a constant 6 psi. Jets are back to stock, 78 main, 82 second. Im thinking of setting the seconds to 83, 84 maybe. My squirter pump is fine, it works, so I dont think thats the problem.
My issue it, she worked amazingly fine, before, then i put the scoop on, still worked fine, then someone tuned it and now it sucks.
As far as trannie goes, I got a BTO TH700R4, level 3, and have 3.55's in the rear. Between 2500 and 3500 while the converter is locked she pulls like no other, its above 4000 that sucks
On the street, shes got great power up to 4000, but after 4000 it just revs and there is no real forward movement, just lacking power, lots of noise, no movement.
On the track, she sputters off the line, then I let off, then floor it, no issues, then it sputters the entire track down, ONLY AT THE TRACK...never on the street.
The whole motor is completley stock, with the exception of a MSD HEI with a 6A box.
Any suggestions for tuning before I go with the secondary jetting trial/error
I have the Gm Perf. Crate ZZ502 Big Block, with the stock Holley Street Avenger carb, 870 cfm.
I put a scoop on there, for sorta like a Ram Air effect. But she hasnt run right for a while now, and Im getting a bit frustrated.
I checked my timing, I set it back 8'c1 BTDC @ 800 rpm; 36'c1 total @ 5000 rpm.
Set my Vac secondary spring back to stock purple, set the Carb to idle mixture stock setting
and checked my bowls for proper level, fuel pressure is good at a constant 6 psi. Jets are back to stock, 78 main, 82 second. Im thinking of setting the seconds to 83, 84 maybe. My squirter pump is fine, it works, so I dont think thats the problem.
My issue it, she worked amazingly fine, before, then i put the scoop on, still worked fine, then someone tuned it and now it sucks.
As far as trannie goes, I got a BTO TH700R4, level 3, and have 3.55's in the rear. Between 2500 and 3500 while the converter is locked she pulls like no other, its above 4000 that sucks
On the street, shes got great power up to 4000, but after 4000 it just revs and there is no real forward movement, just lacking power, lots of noise, no movement.
On the track, she sputters off the line, then I let off, then floor it, no issues, then it sputters the entire track down, ONLY AT THE TRACK...never on the street.
The whole motor is completley stock, with the exception of a MSD HEI with a 6A box.
Any suggestions for tuning before I go with the secondary jetting trial/error
Thread Starter
Intermediate
Joined: Jul 2006
Posts: 38
Likes: 1
From: New Jersey
Intermediate
Joined: Aug 2006
Posts: 31
Likes: 0
From: Lynn Ma.
Good Luck
Russ
Burning Brakes
Joined: Jan 2007
Posts: 1,057
Likes: 4
From: Concord Calif
Hey everyone, I read the loong long post on timing.
I have the Gm Perf. Crate ZZ502 Big Block, with the stock Holley Street Avenger carb, 870 cfm.
I put a scoop on there, for sorta like a Ram Air effect. But she hasnt run right for a while now, and Im getting a bit frustrated.
I checked my timing, I set it back 8'c1 BTDC @ 800 rpm; 36'c1 total @ 5000 rpm.
Set my Vac secondary spring back to stock purple, set the Carb to idle mixture stock setting
and checked my bowls for proper level, fuel pressure is good at a constant 6 psi. Jets are back to stock, 78 main, 82 second. Im thinking of setting the seconds to 83, 84 maybe. My squirter pump is fine, it works, so I dont think thats the problem.
My issue it, she worked amazingly fine, before, then i put the scoop on, still worked fine, then someone tuned it and now it sucks.
As far as trannie goes, I got a BTO TH700R4, level 3, and have 3.55's in the rear. Between 2500 and 3500 while the converter is locked she pulls like no other, its above 4000 that sucks
On the street, shes got great power up to 4000, but after 4000 it just revs and there is no real forward movement, just lacking power, lots of noise, no movement.
On the track, she sputters off the line, then I let off, then floor it, no issues, then it sputters the entire track down, ONLY AT THE TRACK...never on the street.
The whole motor is completley stock, with the exception of a MSD HEI with a 6A box.
Any suggestions for tuning before I go with the secondary jetting
trial/error
I have the Gm Perf. Crate ZZ502 Big Block, with the stock Holley Street Avenger carb, 870 cfm.
I put a scoop on there, for sorta like a Ram Air effect. But she hasnt run right for a while now, and Im getting a bit frustrated.
I checked my timing, I set it back 8'c1 BTDC @ 800 rpm; 36'c1 total @ 5000 rpm.
Set my Vac secondary spring back to stock purple, set the Carb to idle mixture stock setting
and checked my bowls for proper level, fuel pressure is good at a constant 6 psi. Jets are back to stock, 78 main, 82 second. Im thinking of setting the seconds to 83, 84 maybe. My squirter pump is fine, it works, so I dont think thats the problem.
My issue it, she worked amazingly fine, before, then i put the scoop on, still worked fine, then someone tuned it and now it sucks.
As far as trannie goes, I got a BTO TH700R4, level 3, and have 3.55's in the rear. Between 2500 and 3500 while the converter is locked she pulls like no other, its above 4000 that sucks
On the street, shes got great power up to 4000, but after 4000 it just revs and there is no real forward movement, just lacking power, lots of noise, no movement.
On the track, she sputters off the line, then I let off, then floor it, no issues, then it sputters the entire track down, ONLY AT THE TRACK...never on the street.
The whole motor is completley stock, with the exception of a MSD HEI with a 6A box.
Any suggestions for tuning before I go with the secondary jetting
trial/error
There are so many things to check here so where to start? Sounds like you were happy before someone tuned it. So if that is the point of the turn in performance, find out what was changed then and go back to where you were. Don't change jets unless your engine shows it needs it. No one in the world can tell you what your egine needs without looking at plugs and such. You only can get into the ball park only and your there. If you can't find out what was done in your tune-up, then I would check mechanicals first then move to the tune-up. Do compresstion and check for broken valves springs. Check out for vacuum leaks and then get into the tunning after having a solid base to tune from.
Thread Starter
Intermediate
Joined: Jul 2006
Posts: 38
Likes: 1
From: New Jersey
There are so many things to check here so where to start? Sounds like you were happy before someone tuned it. So if that is the point of the turn in performance, find out what was changed then and go back to where you were. Don't change jets unless your engine shows it needs it. No one in the world can tell you what your egine needs without looking at plugs and such. You only can get into the ball park only and your there. If you can't find out what was done in your tune-up, then I would check mechanicals first then move to the tune-up. Do compresstion and check for broken valves springs. Check out for vacuum leaks and then get into the tunning after having a solid base to tune from.
