I've been thinking about this, and some thoughts came into my mind on how larger tires reduce the RPM's at any given speed. This being the case, and the obvious power loss associated with the larger tires, I got to thinking further about the 9 psi pulley. What I want to ask is if anyone thinks that since the RPM's are lower during most driving with the larger tires, could the additional heat buildup using the 9psi pulley over the stock pulley not be so bad, and possibly equal each other out??

I don't know how else to say it.

Chris

 

Sorry Chris, but thats not going to change anything associated with why your truck is not going to make much more power, if any, with a higher psi pulley. Your still fighting the heat issue...the TRD SC's are just not big enough to run more boost through them without some form of intercooling. Yes, more boost right away will yield more power in the lower rpm's, but your probably going to lose top end power (freeway) when you achieve full boost in the higher RPM's. Just like running more boost than a small turbo is supposed to support in its efficiency. More hotter air will help nothing. Now, I have seen one 4runner that is running a bigger pulley and a front mount intercooler, but it looked like it involved quite a bit of fab work.

I'll say it before everyone else does..GEARS will be the only thing to offset the bigger tires

 

I'll say it again: regear! Get some 4.56 gears or 4.88's. If you got the 9.5 p.s.i. pulley you'd probably get ping anyways and then have to buy a TMC 1.1 or something to retard timing a touch. That would likely end up being the sme amount of money too, so just get them gears and you'll be happier. Then if you're still power hungry get a 1st gen. S/C and make a water intercooling system. Then you can add the 9.5 p.s.i. pulley and TMC 1.1 and have loads of power.

Zach

 

Well, for those that don't know, I've got the SMT-6, S/C, 190 high pressure fuel pump, 370cc injectors, and I'm working on a bolt on water cooling system. I can retard and advance timing, control additional injectors for the water injection, so I don't think I'll have a fuel starvation problem, but I might possibly have a detonation problem, unless I can keep the temperatures down enough.

Can someone with a boost guage and stock tires tell me what the boost level is at 80 mph on a flat stretch of road and at what RPM your running at? Thanks!

Chris