build help 4.8 stuff with stroke
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TECH Apprentice
Joined: Dec 2004
Posts: 358
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build help 4.8 stuff with stroke I'm doing a TT ttix setup on a old c5 vette
car already has the setup, but it's time to freshen things up this winter
I'm going to use an l33 block and I'm debating on what stroke
I still need to order pistons, so now is the time!
I have a lunati forged 4.0 stroke crank, and lunati rods already
I also have the stock crank 3.622 (or the 3.2 4.8 crank)
I'm debating going with the longer stroke as the stock crank is likely strong enough for my goals (but at the upper limit)
displacement is also and issue as I'm a bit "turbo limited" with the t3/t4 ttix hybrid turbos (I'll upgrade to champion 3" down pipes plus .82 ar exh housings on the turbo)
My hp goals are 1k hp (around 800 at the tire) total, and I'm looking to run E85 with about 9.5 CR and keeping revs down to around 7k max with 6500 the "norm"
using 127 FIC Bosch injectors
like to hear some suggestions on the stroke or other advice on the build!
car already has the setup, but it's time to freshen things up this winter
I'm going to use an l33 block and I'm debating on what stroke
I still need to order pistons, so now is the time!
I have a lunati forged 4.0 stroke crank, and lunati rods already
I also have the stock crank 3.622 (or the 3.2 4.8 crank)
I'm debating going with the longer stroke as the stock crank is likely strong enough for my goals (but at the upper limit)
displacement is also and issue as I'm a bit "turbo limited" with the t3/t4 ttix hybrid turbos (I'll upgrade to champion 3" down pipes plus .82 ar exh housings on the turbo)
My hp goals are 1k hp (around 800 at the tire) total, and I'm looking to run E85 with about 9.5 CR and keeping revs down to around 7k max with 6500 the "norm"
using 127 FIC Bosch injectors
like to hear some suggestions on the stroke or other advice on the build!
We know the side loading will be much less with the shorter stroke. However, we also know it’s easier to make power with more cubic inches. Personally, I’d be concerned with the aluminum l33 block with the long stroke and the previous mentioned side loading. As I understand they’re not as strong as their iron counterpart. But that’s just my opinion. I’d put a good rod and piston on the short stroke in the aluminum block, run up the boost and rev it.
GEN IV AL Block Strength Hi RK, I like the GEN-IV AL block with a bore of 98mm. (very thick walls)
I would use your 4.00" crank and rods.
The reason is the turbo size and air flow.
The stroke increase will make more power with LESS air flow due to the LOWER RPM.
Air Flow is MORE related to RPM than displacement.
I could provide Racetech Pistons at a great price.
There could be some luck with the engine balance if you know the Bob Weigh AND Rod Big/Small weights ?
Lance
I would use your 4.00" crank and rods.
The reason is the turbo size and air flow.
The stroke increase will make more power with LESS air flow due to the LOWER RPM.
Air Flow is MORE related to RPM than displacement.
I could provide Racetech Pistons at a great price.
There could be some luck with the engine balance if you know the Bob Weigh AND Rod Big/Small weights ?
Lance
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Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
I would definitely use the 4" crank. I don't see the side loading being any worse than any other time people use 4" cranks. The small bore blocks have pretty thick sleeves, it shouldn't be an issue.
The extra cubes will make better use of the turbos at a lower rpm, which should keep you from outrunning your turbos.
What heads/cam/intake are you using with this shortblock?
The extra cubes will make better use of the turbos at a lower rpm, which should keep you from outrunning your turbos.
What heads/cam/intake are you using with this shortblock?
