[Gary H]

Hi all
Current set up is Roto-fab to TM ported TB, into Jokerz fullt-tilt LT4 charger with a NX ported lid and out through coated TSP longtubes, no cats.
Will also be adding water meth injection, 4 ports into the lid, one into the inlet pre-TB.

Looking at Pulleys. Having looked at the various charts, a 2.3" upper will give me an 8.7% increase in the blower ratio, an 8.6" lower will give me 7.5% and both will give me 18.65% (Weapon X figures) These are the two I'm interested in as I think they're the 'safest' in terms of combos and my supporting mods (purely from my own research).

So the question is two fold:
1) If you were just doing one Pulley, which one and why?
2) Do I have the supporting mods to do both?

Thanks in advance

[McBrayer]

WeaponX pulley and belt charts are all kinds of jacked up. Their charts have failed my twice on what belt will fit what combo.

It sounds like you are on pump 93 only and not E85 since you didn't mention it.

Bigger lower pulleys are always better than smaller upper pulleys. A bigger pulley equals more belt contact (less chance of belt slip). I had a 9.55" lower and Griptec 2.3" upper (on E70) and experienced a lot of belt slip at the upper.

If you are on 93 only, then a 9.45 or 9.55 (depends on brand) lower with a stock upper will put you near the top of the "safe street" boost levels with 93. You could run a 9.55 lower and 2.3 upper on 93, but it would really be pushing your luck IMHO.

[Gary H]

Thank you for the reply, appreciated and it makes a lot of sense now.
We have 99RON here, so between 93-94 pump with a max of 5% Ethanol, so makes no difference.
So a 9.45" giving me 18% O/D without an upper...whilst I get less chance of slip, I heard somewhere that 15% o/d is really as far as you want to go, or is that being conservative?

[JasonSB]

I have 15% overdrive and still have fuel left on 93. You could probably go with 18% overdrive and be fine.

[EDFHOBBIES]

Gary.. while the blower was off you should of done the upper would of only been out the part cost, now if you do the upper you will have some added labor.. Not putting ya down just if someone else reads post and going your direction it will save them 250.00 or so...

93 only do the upper or lower only but not both.. I prefer the lower because changes are a lot easier just initial install is a tad more work.

If you are going meth route do the upper and lower with better exchangers or something to increase capacity(trunk tank)..

driving with my tuner 2 weeks ago my cars 1000 hp and the oem exchanger was keeping it cool no problem so I think its added capacity more than anything..

900 to 1200 for the 3 exchangers is about the same cost as a universal trunk mount system and install if you get the ones from summit 7.5 gal with rule pump.. they are universal and you will lose some trunk vs paying custom and it all fitting under the carper(weapon x /complete street) or losing some trunk on drivers side(cordes)..

just a few ideas and thoughts..


scratch that you have 98 octane available over there.. that maybe the ticket maybe you won't need meth and can do both the lower and upper..

Probably need a tuner to answer this...

[Gary H]

Hey bud, appreciate the input. I've actually followed your original route and gone with the 15% lower. This will scratch the itch until the 2650 urge becomes too strong