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Our wheels are considerably larger and the downpipe flange is immense compared to normal T4’s. This turbo on a 408 has done 1100 at 25 lbs. and has enough extra it can lift heads unless “specialer” stuff is used to hold them down. You might be looking at a couple hundred over what you have currently when you turn it up to the same net turbine inlet backpressure ratio. Meaning it might be 36 instead of 26 lbs, BUT where your old turbo was done, this one still has a lot of overhead before T.I.P. strangles it to the same extent. So when you get your number, simply saying “I added more boost” doesn’t really explain it. You would need to tell folks the turbo “allowed you to add more boost reliably” if that makes sense.
With the various ways people measure and figure horsepower these days, the biggest thing is for you to use the same methodology as you make changes.
What size is the turbo you're comparing in these pictures? Is there a special downpipe v-band that the Summit turbo utilizes? Also, do you have a link to the 408 you reference that made 1100 wheel with your turbo?
What size is the turbo you're comparing in these pictures? Is there a special downpipe v-band that the Summit turbo utilizes? Also, do you have a link to the 408 you reference that made 1100 wheel with your turbo?
Thanks.
Hi Razor. The turbo is JP’s old 78/75 V2. The downpipe is 4”, so still common….just not for a T4 . It is important to run a 4” out of it to hit the HP targets and not be a constriction. 103mm/25.4=4.055” as an example.
We cannot share the 408 dyno with you but it’s from a trustworthy source.
BUMP- This turbo is still rockin, 3 years later! Still on an SBE 5.3, and going 8.5@171mph which is the fastest SBE+ Manual LS, anything ever.
Turbo has a lot to give, but I am currently floating valves at anything above 30ish psi. I am not sure how much further I am willing to take the SBE, we will see, but the turbo absolutely kicks A$$!
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. It is important to run a 4” out of it to hit the HP targets and not be a constriction. 103mm/25.4=4.055” as an example.
