Will i need a new tune?
Thread Starter
Intermediate
Joined: Aug 2019
Posts: 46
Likes: 1
From: Voluntown, CT
Will i need a new tune?
So my 98 is just about full bolt on with a cam. Car is dyno tuned with those mods.. I just got an ls6 intake manifold and plan on installing it. Will I need a new tune just for the mani? or do you guys think it will be okay?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Theoretically, YES you will!! In actuality the car will run fine.
Will it run the best it can? NO.
Anytime that you change the air flow of the engine by altering something between the MAF and the MUFFLERS, it does effect the tune. How much it effects the tune, is what is in question.
Do this: Get some data logging/scanning software and look at the LONG TERM FUEL TRIMS (LTFT) and SHORT TERM FUEL TRIMS (STFT). After you change the manifold, re-examine them again. If the LTFT are far from being slightly negative, your tune needs to be adjusted. The part of the tune that will most likely be effected is the Volumetric Efficiency (VE) tables and the Wide Open Throttle (WOT) Fuel Trim AFR.
All of that can be checked without doing a tune. Its called data logging. There are phone APP software products that you can purchase to do this monitoring. If the tune is way off, get a retune to get all the power that's on the table. If it a little off,, just live with it. You will also need a Wide Band AFR meter to check the WOT AFR.
The WOT AFR is where you make all your power. If its very rich or lean, it can severely effect engine performance and longevity.
My 2 cents
Bill
Will it run the best it can? NO.
Anytime that you change the air flow of the engine by altering something between the MAF and the MUFFLERS, it does effect the tune. How much it effects the tune, is what is in question.
Do this: Get some data logging/scanning software and look at the LONG TERM FUEL TRIMS (LTFT) and SHORT TERM FUEL TRIMS (STFT). After you change the manifold, re-examine them again. If the LTFT are far from being slightly negative, your tune needs to be adjusted. The part of the tune that will most likely be effected is the Volumetric Efficiency (VE) tables and the Wide Open Throttle (WOT) Fuel Trim AFR.
All of that can be checked without doing a tune. Its called data logging. There are phone APP software products that you can purchase to do this monitoring. If the tune is way off, get a retune to get all the power that's on the table. If it a little off,, just live with it. You will also need a Wide Band AFR meter to check the WOT AFR.
The WOT AFR is where you make all your power. If its very rich or lean, it can severely effect engine performance and longevity.
My 2 cents
Bill
Last edited by Bill Curlee; Aug 15, 2019 at 09:19 AM.
Drifting
Joined: May 2007
Posts: 1,550
Likes: 324
From: Mid Ohio
I've done some tuning on fords... In the tune there is a place to enter intake volume. A small trick some tuners do (and I did too) is to enter a volume that is 1/2 of the actual volume. This gives a bit better tip in response. (makes the throttle feel slightly more responsive in every part throttle situation)
I even tried toying with the volume calc by changing in small percentages up and down. It didn't make much difference either way.
IMO if the MAF and TB are the exact same parts that were used during your dyno tune.... you'll be ok w/o a tune.
(TB and MAF are "inputs" to the tune so changing those physical parts will require a tune change)
Just make sure there are no leaks after the R&R. Use a smoke machine if possible. Intake manifold leaks (and exhaust leaks) have lead many a DIY'er down false paths of repair for many yrs.
I even tried toying with the volume calc by changing in small percentages up and down. It didn't make much difference either way.
IMO if the MAF and TB are the exact same parts that were used during your dyno tune.... you'll be ok w/o a tune.
(TB and MAF are "inputs" to the tune so changing those physical parts will require a tune change)
Just make sure there are no leaks after the R&R. Use a smoke machine if possible. Intake manifold leaks (and exhaust leaks) have lead many a DIY'er down false paths of repair for many yrs.
Last edited by wydopnthrtl; Aug 15, 2019 at 10:15 AM.
Thread Starter
Intermediate
Joined: Aug 2019
Posts: 46
Likes: 1
From: Voluntown, CT
Theoretically, YES you will!! In actuality the car will run fine.
Will it run the best it can? NO.
Anytime that you change the air flow of the engine by altering something between the MAF and the MUFFLERS, it does effect the tune. How much it effects the tune, is what is in question.
Do this: Get some data logging/scanning software and look at the LONG TERM FUEL TRIMS (LTFT) and SHORT TERM FUEL TRIMS (STFT). After you change the manifold, re-examine them again. If the LTFT are far from being slightly negative, your tune needs to be adjusted. The part of the tune that will most likely be effected is the Volumetric Efficiency (VE) tables and the Wide Open Throttle (WOT) Fuel Trim AFR.
All of that can be checked without doing a tune. Its called data logging. There are phone APP software products that you can purchase to do this monitoring. If the tune is way off, get a retune to get all the power that's on the table. If it a little off,, just live with it. You will also need a Wide Band AFR meter to check the WOT AFR.
The WOT AFR is where you make all your power. If its very rich or lean, it can severely effect engine performance and longevity.
My 2 cents
Bill
Will it run the best it can? NO.
Anytime that you change the air flow of the engine by altering something between the MAF and the MUFFLERS, it does effect the tune. How much it effects the tune, is what is in question.
Do this: Get some data logging/scanning software and look at the LONG TERM FUEL TRIMS (LTFT) and SHORT TERM FUEL TRIMS (STFT). After you change the manifold, re-examine them again. If the LTFT are far from being slightly negative, your tune needs to be adjusted. The part of the tune that will most likely be effected is the Volumetric Efficiency (VE) tables and the Wide Open Throttle (WOT) Fuel Trim AFR.
All of that can be checked without doing a tune. Its called data logging. There are phone APP software products that you can purchase to do this monitoring. If the tune is way off, get a retune to get all the power that's on the table. If it a little off,, just live with it. You will also need a Wide Band AFR meter to check the WOT AFR.
The WOT AFR is where you make all your power. If its very rich or lean, it can severely effect engine performance and longevity.
My 2 cents
Bill
Thread Starter
Intermediate
Joined: Aug 2019
Posts: 46
Likes: 1
From: Voluntown, CT
I've done some tuning on fords... In the tune there is a place to enter intake volume. A small trick some tuners do (and I did too) is to enter a volume that is 1/2 of the actual volume. This gives a bit better tip in response. (makes the throttle feel slightly more responsive in every part throttle situation)
I even tried toying with the volume calc by changing in small percentages up and down. It didn't make much difference either way.
IMO if the MAF and TB are the exact same parts that were used during your dyno tune.... you'll be ok w/o a tune.
(TB and MAF are "inputs" to the tune so changing those physical parts will require a tune change)
Just make sure there are no leaks after the R&R. Use a smoke machine if possible. Intake manifold leaks (and exhaust leaks) have lead many a DIY'er down false paths of repair for many yrs.
I even tried toying with the volume calc by changing in small percentages up and down. It didn't make much difference either way.
IMO if the MAF and TB are the exact same parts that were used during your dyno tune.... you'll be ok w/o a tune.
(TB and MAF are "inputs" to the tune so changing those physical parts will require a tune change)
Just make sure there are no leaks after the R&R. Use a smoke machine if possible. Intake manifold leaks (and exhaust leaks) have lead many a DIY'er down false paths of repair for many yrs.
