Benifits of changing from 48mm to 52mm TB on 383 LT1
10-22-2009, 08:29 PM
#1
Benifits of changing from 48mm to 52mm TB on 383 LT1
Currently running 405 rwhp and 420lbft (mustang dyno) with the 48mm and good low end torque.
1) Is it worth changing to a 52mm TB knowing low end torque is more imporant than peak power?
2) How much will it impact low end torque?
3) Does the computer need to be reprogrammed? Dynoed and tuned for current setup.
1) Is it worth changing to a 52mm TB knowing low end torque is more imporant than peak power?
2) How much will it impact low end torque?
3) Does the computer need to be reprogrammed? Dynoed and tuned for current setup.
10-22-2009, 09:00 PM
#3
Melting Slicks
If you have data logs from the dyno runs and the manifold pressure less than atmospheric then yes a good plan if the same not worth the effort. If you have no data logs why not?
Dave
Dave
10-22-2009, 10:13 PM
#6
Le Mans Master
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I would say if it does impact low end torque, it would be a smalla mount (not noticable) but would improve peak HP and throttle response. However if the manifold pressure is the same as the outside like mentioned, than it probably wont do much.
10-22-2009, 10:28 PM
#7
Safety Car
The only way to know IS to actually try it. Its a fact that throttle bodies can limit power as witnessed in all forms of motor racing (restrictor plates etc). If you want to increase performance what power you produce through your powerband that the engine sees between shifts ( guessing here to lazy to check 4500-6000 rpm) matters the most, NOT what happens at 2000 rpm if your motor makes peak torque down low. Its also a fact that horsepower is the stat that matters more than torque.
At peak torque your engine is consuming the most amount amount of air and if you get more torque out of a 52 then it is definitely beneficial.
At peak torque your engine is consuming the most amount amount of air and if you get more torque out of a 52 then it is definitely beneficial.
10-23-2009, 12:40 AM
#8
Drifting
Good to know that the 48 can support 405 wheel HP......I don't think I will ever change mine, it being a L98. Some people are running 58's on there 350 TPI's. I plan on some 190cc heads, ported Edelbrock base and siamesed SLP's, and a Lunati 60102 Voodoo cam. I would guess that your combo would see a increase with the larger throttle body.
10-23-2009, 03:41 AM
#9
Thanks for your input. If I change to a 52mm TB will it require a change to the program? Can it alter driveability and dramatically change AFR with a different TB? Right now it is a pretty conservate AFR about 12.6. As a side note this is a speed density system.
Last edited by pelensky; 10-23-2009 at 07:13 AM.
10-23-2009, 05:35 AM
#10
Currently running 405 rwhp and 420lbft (mustang dyno) with the 48mm and good low end torque.
1) Is it worth changing to a 52mm TB knowing low end torque is more imporant than peak power?
2) How much will it impact low end torque?
3) Does the computer need to be reprogrammed? Dynoed and tuned for current setup.
1) Is it worth changing to a 52mm TB knowing low end torque is more imporant than peak power?
2) How much will it impact low end torque?
3) Does the computer need to be reprogrammed? Dynoed and tuned for current setup.
10-23-2009, 05:56 AM
#11
Le Mans Master
10-23-2009, 06:11 AM
#12
Le Mans Master
On the first car in my signature I changed from a 48 to a 52 and seen no changes at all. (track test only) I never had it re-tuned though.
As far as alter the driveability, I didnt see any difference, but I believe it could make the gas feed "feel" more sensitive due to more volume with less opening but again, I didnt notice it.
10-23-2009, 08:03 AM
#13
Safety Car
Currently running 405 rwhp and 420lbft (mustang dyno) with the 48mm and good low end torque.
1) Is it worth changing to a 52mm TB knowing low end torque is more imporant than peak power?
2) How much will it impact low end torque?
3) Does the computer need to be reprogrammed? Dynoed and tuned for current setup.
1) Is it worth changing to a 52mm TB knowing low end torque is more imporant than peak power?
2) How much will it impact low end torque?
3) Does the computer need to be reprogrammed? Dynoed and tuned for current setup.
-Since you have a speed density system it may lean out the AFR but since you are running 12.6 AFR at WOT it may end up leaning it out to a still safe AFR of 12.7 or 12.8?
-I would put a vacuum gauge on the intake and make a high RPM WOT pull, if you see manifold vacuum the 52mm throttle body may provide a power increase if it is the restriction. To really know, put a vacuum gauge ahead of the throttle body to see if the air cleaner is the restriction.
10-23-2009, 08:05 AM
#14
Safety Car
At peak torque the engine has the highest VE but not the highest CFM readings. The highest CFM reading will occur at or near peak HP.
10-23-2009, 10:04 AM
#15
Le Mans Master
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Is your intake ported or is the opening still 52mm? I'd get the intake done first by a pro shop. It should cost around $200 and probably good for another 10+ hp. As for the TB.. there's a reason why 99% of all LT1 builders and performance shops recommend a 58mm for all out builds. I would do it and get it retuned.
10-23-2009, 11:43 AM
#17
Safety Car
10-23-2009, 12:21 PM
#18
Drifting
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Most 383-396 LT1's have had good success with the 52mm TB.
10-23-2009, 03:42 PM
#20
Le Mans Master