2.87" pulley on T-trim stock bottom end LS3?
01-15-2014, 03:51 PM
#1
2.87" pulley on T-trim stock bottom end LS3? I'm currently running a 3.125" blower pulley and a 7.5" stock diameter crank pulley with my A&A T-trim kit. I see 12psi when I shift at 6700-6800. I was thinking about putting the 2.87" pulley on that a buddy sold me. I have a direct drive, so I'm not worried about slip. What say you all? Am I crazy for wanting to try it?
01-16-2014, 01:06 AM
#2
Well you know I'd hate to see you pop that motor but heres some info FWIW.
The t-trim you have has a max recommend impeller speed of 55,000 rpm. Your currently spinning it to 57,960 (at 7000 rpm engine speed).
With the new pulley you would be spinning the impeller 63109.7 at the same 7000 engine rpm. Now its not uncommon to overspin the votech headunits a good bit. I would not be overly concerned for the blower but the LS3 of yours well may not be as happy about the extra cylinder pressure. Additionally the tires you have will more than likely be crying more than usual.
That being said, as long as your willing to further push your setup, go for it man.
The t-trim you have has a max recommend impeller speed of 55,000 rpm. Your currently spinning it to 57,960 (at 7000 rpm engine speed).
With the new pulley you would be spinning the impeller 63109.7 at the same 7000 engine rpm. Now its not uncommon to overspin the votech headunits a good bit. I would not be overly concerned for the blower but the LS3 of yours well may not be as happy about the extra cylinder pressure. Additionally the tires you have will more than likely be crying more than usual.
That being said, as long as your willing to further push your setup, go for it man.
01-16-2014, 01:57 AM
#3
Meth certainly helps but I'd be weary of that much boost on a stock bottom end and overspinning the charger that much. You loose a lot of efficiency (read: increased iat) overspinning the impeller. 8000rpm is a fair bit too. It may be time to consider a Ysi and forged bottom before a rod takes your nice LS3 block out.
01-17-2014, 09:15 AM
#4
I have an oil fed unit with the HD bearings, so overspinning it should be okay. IAT's drop to 20F and creep back up to around 40F during a 4th gear pull. I think I'm going to try it. I was also thinking about experimenting with a 80/20 meth/water mix. I already called Schwanke about building me an iron block 408 to replace my LS3. If the LS3 lives I'll probably save it for a new project. Either a 67-68 Impala fastback or a Miata.
Last edited by TurboAv; 01-17-2014 at 09:22 AM.
01-25-2014, 04:45 PM
#7
It probably won't make as much as when I had it on E85 with the 3.125". I may throw a tank of E85 in and lean on it just to see. It's the cap that comes with the Holley valve covers. I went with the natural finish because it looks stock. No more stupid coil bracket. http://www.holley.com/241-88.asp