NEW HPI modified 54mm FBW TB's
#1
NEW HPI modified 54mm FBW TB's
I had my first opportunity to install one of the new HPI modified FBW 54mm TB's this weekend. I saw them at the HPI booth in Cincinnati in February, but this is the first one I've installed.
The bike was an 08 SG with a TMan Stage 2 107 that had 1.800 intake ports (by request), with TR625 cams. The original TB used on the build was an HPI modified S/E 58 MM unit. We used it because we had to have a piece with 1.800" intake ports rather than the stock 1.670's. While it worked well and made good "numbers", and the owner was quirt happy, I felt the TB was too big and was making it a little more "lazy" than I thought it should have been. Like I said the owner was happy and unsure I could make it better.
We sent his stock FBW TB in to HPI for their 54mm rework and requested they fit it with the required 1.800" intake.
The unit came back looking KICKAZZ! Notice the new intake has a "Y" shape compared to the stock units "T". THis is much better as and helps control & keep separate the charge for each respective cylinder…
HPI 54mm Modified stock TB on left, HPI modified S/E 58mm on right
another angle…
and a 3rd….
Notice how you can see through the S/E on the right, but not nearly so much on the new unit on the left
Here's a look at the throats. Bigger is NOT ALWAYS BETTER!
one final look…
So, with the new unit on (same injectors), the bike fired right up. It will have to be retuned, but even as it sits, the throttle response is much quicker & crisper. I rode it in the parking lot & showed my buddy that his bike DOES do wheelies on demand! Now, it has the feel I was looking for. It's CRISP & snappy. Can't wait to try it after it's retuned!!!!
The bike was an 08 SG with a TMan Stage 2 107 that had 1.800 intake ports (by request), with TR625 cams. The original TB used on the build was an HPI modified S/E 58 MM unit. We used it because we had to have a piece with 1.800" intake ports rather than the stock 1.670's. While it worked well and made good "numbers", and the owner was quirt happy, I felt the TB was too big and was making it a little more "lazy" than I thought it should have been. Like I said the owner was happy and unsure I could make it better.
We sent his stock FBW TB in to HPI for their 54mm rework and requested they fit it with the required 1.800" intake.
The unit came back looking KICKAZZ! Notice the new intake has a "Y" shape compared to the stock units "T". THis is much better as and helps control & keep separate the charge for each respective cylinder…
HPI 54mm Modified stock TB on left, HPI modified S/E 58mm on right
another angle…
and a 3rd….
Notice how you can see through the S/E on the right, but not nearly so much on the new unit on the left
Here's a look at the throats. Bigger is NOT ALWAYS BETTER!
one final look…
So, with the new unit on (same injectors), the bike fired right up. It will have to be retuned, but even as it sits, the throttle response is much quicker & crisper. I rode it in the parking lot & showed my buddy that his bike DOES do wheelies on demand! Now, it has the feel I was looking for. It's CRISP & snappy. Can't wait to try it after it's retuned!!!!
Last edited by PhilM; 07-18-2010 at 05:14 PM.
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