Whipple guys...anyone getting away with running the 3.5 pulley with good 93?

I have a gen3 with a 3.625 pulley making 13.4 psi @ 7800(I have stock cats). I am seeing -4 KR values at that level running a max of 17.5 timing.

I know I have good gas and my tune is conservative.

I'd like to swap to a 3.5 pulley on my 93 tune leaving the conservative tune in place, then have a more aggressive 100 octane tune with more boost and timing.

Anyone having luck running good 93 with the 3.5 pulley?

I wouldn't. Not worth the risk IMO. don't think many tuners will either

Agreed. 13# is about where you want to stop on 93 without additives.

Mine was not happy with 3.5" and 93 w/long tubes.

I did some testing last year with 2 other cars so 3 all together. On 93 and 3.5" produced plus 4 and more. For me even 3.625" produced plus 2 which isn't bad but not clean either. Stock manifolds as well.

If you only run it on 100 octane should be fine.

I agree on 93 not a good decision. Just swap tunes when you swap pulleys and gas.

My tuner did not feel comfortable letting me run with the 3.5 on 93. 93 plus some octane booster is no problem though.

Dont do it. I have 3.5 on E85

93 3.5" no cats.. adding 3 degrees of timing all day.. stepping down to 3.375" on ms109

bklynpanman said:

93 3.5" no cats.. adding 3 degrees of timing all day.. stepping down to 3.375" on ms109

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:cheers:

Whats your total timing up top?

Seems like the guys making it work don't have cats.

Is that just because its making the whole set up more efficient?

SVT-DADDY said:

:cheers:

Whats your total timing up top?

Click to expand...

will get you that info asap

SVT-DADDY said:

Seems like the guys making it work don't have cats.

Is that just because its making the whole set up more efficient?

Click to expand...

Yes less back pressure less boost, but more efficiency and power. Back pressure = more boost higher cylinder pressure and need for more octane.

On my gen 3 I ran 3.5 daily on 93
I’m back on 3.625 now since gas prices are up

But yes it was running out of fuel after 6k rpm added a bap fixed that
Tunner said my logs look great
I’m also on 150mm Tb DD149 intake and id1050x injectors

I’ve seen more than one Aussie car running a 3.5” pulley on our 98 (RON). No idea how much timing they had to pull to make it work or even if it was a really viable option.
I won’t be doing it, put it that way.