I have an 87 4 Runner with a stock 4 cylinder 5 speed manual that I was planning on installing a 3" body lift and mounting 33/12.50/15 tires on. I recently heard that mounting 33" tires would greatly reduce power in my engine and make my fifth gear almost useless?? Would I be better off mounting 31" tires or do I need to upgrade my gears? Or will it not affect my engine performance at all? Any information on this would be greatly appreciated!

Mike

it won't affect your engine performance at all. however your gearing will limit your engine's ability to push your tires around as easily. by going to deeper gears, you take resistance off of the engine by a significant amount. 33s will work, but you probably won't see 5th gear very much unless you do a lot of dowhill or flat land driving.

if you want to run 33s, finding 4.88 gears would be the best(albeit most expensive) way to go, or just run 31s for now

Thanks for the help!

By the way, I put 33X12.5 tires on my truck (No body lift) and found that even with the turbo and probably around 150 hp that 4th gear got used a ton more than same setup with 31X10.5's. I saw that the turbo was on almost all the time with the bigger tires, indicating a big hit in gas mileage. Overall acceleration was still good and the truck was still pretty quick.

A buddy of mine is running 32's on his '86 Runner with EFI, and he does o.k. If you aren't planning on a gear change any time soon, and just want bigger tires, to help with the power loss, you could run a header/highflow cat, and upgrade the ignition and cam.

If you are going to gop with a BL first I would recommend going with only a 2". With a 2" BL 32's clear w/o rubbing, and you can clear 33's with a little rubbing. 2" BL's also look cleaner IMO, and are easier to install. The '86 I am selling has 33x12.50's onn 8" rims with a 2" BL. Since it is a truck I haven't noticed that much power loss(though haven't been on the open highway with it.

Here's my old 87 turbo 4Runner with 32's, add-a-leafs in the rear and cranked up torsion bars. No rubbing and no body lift needed.

Perceived powerloss will depend a lot on the size and weight of a tire too. EX: A 33x12.50 dunlop will probably be a 32 and weigh 12-15 lbs less than a true 33" swamper.

If you want 33s, I'd start looking around for factory 4.56 or 4.88 thirds on somewhere like www.car-part.com

Really, if you want 33s be patient and find the 4.88s. I got the 4.56s and regret not looking harder for 4.88s if I want to go bigger (which I do) down the road.


And the other guys are right. A 2" body with 33x12.50s on an 8" will clear find. Cut some plastic in the wheel wells.

Would anyone care to remind those of us who have forgotten...

Which models/years had factory 4.88s? And will a complete diff assembly from one of these vehicles drop in to the stock axle housings on my '85 runner?

1992 to 1995 V6 Automatic 4x4 trucks and 4Runners.
Yes, it will pop right in to your existing rear axle housing. (front too!!!!, on solid axle trucks.) That's whats in my '85 4Runner. A rear 4.88 diff from a '94 pickup in the rear, and a rear '93 4Runner diff in the front. Both used 4.88 complete 3rd members $150 each <img src="/forums/images/graemlins/kewl.gif" alt="" />

ok, just want to clarify a bit more. Going from 4.10 to let's say 4.88, I need to 2 third members (front & rear) with the same ratios right?

& V6/turbo thirds cannot be put in 4cyl thirds or the other way around?