Gibbo205
Well-Known Member
Stock GT vs 350 Throttle Bodies: Dyno Tested!
Quote my previous results for easy comparison which was of the GT 350 throttle body fully optimised make 29-30 degrees timing WOT with no positive knock.
Unfortunately I removed the 350 TB due to poor drive ability particular on cold starts, the throttle was too sensitive, almost on/off like causing the car to feel jerky/jumpy when cold, once warm it was much improved though still not perfect.
So I re-fitted the stock throttle body and got Lund to dial the tune in, once again the car is making a solid 29-30 degrees timing WOT with no positive knock. I still found the throttle a tad sensitive at first, much also be as a result of running so much timing down low as well as up top, but I requested Lund reset my throttle maps and drive by wire setting to the Ford stock settings, which has cured the issues.
Stock TB vs 350 TB
So ignore the results below 3000rpm as always that is the dyno loading up. So torque and power curve remains absolutely identical between the two throttle bodies.
Remember the tune on both runs was fully dialled in and had about 200 miles on each tune before visiting the dyno and even better ambient temperatures for both runs was 7c with similar humidity so environmental conditions were pretty identical.
Now at 6200rpm we see the larger 87mm throttle body coming into play with around a 5BHP gain which builds to nearly 10BHP by around 6500rpm and then reduced back down to around 8BHP by around 7000rpm.
So yes the bigger throttle body makes more power for sure, it depends how you consider 10BHP, can I feel it on the road? No! If anything the car feels better, but the chances of ever feeling 10BHP on a 500BHP car is likely never.
We still had the same top speed limiter issue, it seems to be dyno related, but for comparison sake it makes for a fair ocmparison.
However to check the car did not have an RPM limiter we did a run in 4th gear just to also check the stock TB carries on making power:
So you can see, the stock TB is costing nothing at the top-end, the car continues to make power beyond 7000rpm, infact a further 20BHP is made beyond 7000rpm on the stock throttle body. I did not let the dyno operator rev beyond 7500rpm simply as I am on stock OPG/Sprocket and when they clutch in for coastdown you get a rev spike of around +500rpm, so reving to 8000rpm means a spike of 8500rpm or hitting the limiter hard and whilst I am on stock OPG/Sprocket I am staying well out of that limiter.
CONCLUSION
- Stock TB drives much better when cold and slightly smoother when warm.
- 350 TB has an on/off jerky feel when cold and is still marginally jumpy when warm
- 350 TB makes 5-7WHP additional beyond 6000rpm.
- Both throttle bodies maintain power curves.
- Stock TB makes NO additional torque down low, curves are identical!
- NOW YOU SEE WHY IT IS IMPORTANT TO RUN THE GEAR CLOSEST 1:1, running 3rd or 4th gives lower in-accurate results, 5th is 1:1, if you ran 6th you'd get crazy high torque figure!
So draw your own conclusions, if your a dyno queen or a drag racer the 350 TB will give you upto 10HP more and a potential 0.1s faster quarter and an additional 1-2mph on trap speed.
If you use your car as a daily the stock TB drives nicer but makes no additional power or torque anywhere when a car is fully dialled in on both throttle bodies.
One thing I am going to check with Lund on is if in my final 350 TB tune did they try just running Ford stock throttle maps and DBW settings like I am running on the stock TB. As that could help a lot, though Lund did say tuning the throttle maps and DBW on the 350 TB is an absolute nightmare with it being a GM part and SCT software does not recognise it correctly. So it could be that HP tuners software can better dial in the 350 TB if doing the throttle maps and DBW software works in HP tuners?
Anyway I hope this helps, this comparison could not get any fairer, same dyno, same operator, same ambient conditions, same gear, same fuel, both tunes fully dialled in.
Simple facts are stock TB or 350 TB, you still have a solid 500HP crank on a RHD car, so a LHD car is going to be around 515-525HP crank for sure on this setup, that is Shelby GT 350 power with more torque!
Final Conclusion
516BHP & 396lb/ft (Lund tune and full GT 350 setup)
Quote my previous results for easy comparison which was of the GT 350 throttle body fully optimised make 29-30 degrees timing WOT with no positive knock.
Unfortunately I removed the 350 TB due to poor drive ability particular on cold starts, the throttle was too sensitive, almost on/off like causing the car to feel jerky/jumpy when cold, once warm it was much improved though still not perfect.
So I re-fitted the stock throttle body and got Lund to dial the tune in, once again the car is making a solid 29-30 degrees timing WOT with no positive knock. I still found the throttle a tad sensitive at first, much also be as a result of running so much timing down low as well as up top, but I requested Lund reset my throttle maps and drive by wire setting to the Ford stock settings, which has cured the issues.
Stock TB vs 350 TB
So ignore the results below 3000rpm as always that is the dyno loading up. So torque and power curve remains absolutely identical between the two throttle bodies.
Remember the tune on both runs was fully dialled in and had about 200 miles on each tune before visiting the dyno and even better ambient temperatures for both runs was 7c with similar humidity so environmental conditions were pretty identical.
Now at 6200rpm we see the larger 87mm throttle body coming into play with around a 5BHP gain which builds to nearly 10BHP by around 6500rpm and then reduced back down to around 8BHP by around 7000rpm.
So yes the bigger throttle body makes more power for sure, it depends how you consider 10BHP, can I feel it on the road? No! If anything the car feels better, but the chances of ever feeling 10BHP on a 500BHP car is likely never.
We still had the same top speed limiter issue, it seems to be dyno related, but for comparison sake it makes for a fair ocmparison.
However to check the car did not have an RPM limiter we did a run in 4th gear just to also check the stock TB carries on making power:
So you can see, the stock TB is costing nothing at the top-end, the car continues to make power beyond 7000rpm, infact a further 20BHP is made beyond 7000rpm on the stock throttle body. I did not let the dyno operator rev beyond 7500rpm simply as I am on stock OPG/Sprocket and when they clutch in for coastdown you get a rev spike of around +500rpm, so reving to 8000rpm means a spike of 8500rpm or hitting the limiter hard and whilst I am on stock OPG/Sprocket I am staying well out of that limiter.
CONCLUSION
- Stock TB drives much better when cold and slightly smoother when warm.
- 350 TB has an on/off jerky feel when cold and is still marginally jumpy when warm
- 350 TB makes 5-7WHP additional beyond 6000rpm.
- Both throttle bodies maintain power curves.
- Stock TB makes NO additional torque down low, curves are identical!
- NOW YOU SEE WHY IT IS IMPORTANT TO RUN THE GEAR CLOSEST 1:1, running 3rd or 4th gives lower in-accurate results, 5th is 1:1, if you ran 6th you'd get crazy high torque figure!
So draw your own conclusions, if your a dyno queen or a drag racer the 350 TB will give you upto 10HP more and a potential 0.1s faster quarter and an additional 1-2mph on trap speed.
If you use your car as a daily the stock TB drives nicer but makes no additional power or torque anywhere when a car is fully dialled in on both throttle bodies.
One thing I am going to check with Lund on is if in my final 350 TB tune did they try just running Ford stock throttle maps and DBW settings like I am running on the stock TB. As that could help a lot, though Lund did say tuning the throttle maps and DBW on the 350 TB is an absolute nightmare with it being a GM part and SCT software does not recognise it correctly. So it could be that HP tuners software can better dial in the 350 TB if doing the throttle maps and DBW software works in HP tuners?
Anyway I hope this helps, this comparison could not get any fairer, same dyno, same operator, same ambient conditions, same gear, same fuel, both tunes fully dialled in.
Simple facts are stock TB or 350 TB, you still have a solid 500HP crank on a RHD car, so a LHD car is going to be around 515-525HP crank for sure on this setup, that is Shelby GT 350 power with more torque!
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