I have a Toyota mud truck with an 04 5.3 with ARP rod bolts, Ls6 cam, 918 springs, and a Maggie 122. I am taking it out this Saturday and was thinking about raising the fuel cut off limiter from 6200 to 6800. The reason I want to do that is beacuse the engine dones not make enough power to allow me to shift to second gear while in 4WD. It falls on its face, so I thought if I only have 1st gear maybe I could get a little more wheel speed by raising engine RPM. I know the engine will be well above its peak torque, but if itll turn that high and be safe it would help alot.

BTW its a 4L80E, 1 ton axles with 5.13s turning cut 44" Boggers.

Next year I hope to swap in a Gt2-3 or a VHP Trucker, E85 and a 2.8" pulley. I currently have a 3.2" installed and it made 369 rwhp in 2nd gear on 38" tires at 6.4#s.

Do you guys forsee engine damage if I turn it to 6800?

 

Magnacharger suggest 18,000 as a max RPM (from what I have heard). Take your snout pulley and divide by your crank pulley to get the ratio, then multiply by engine RPM's.

Current:
7" / 3.2" equals 2.1875 ratio X 6800 rpm's equals 14,875 rotor rpm's

7" / 2.8" equals 2.5 ratio X 6800 rpm's equals 17,000 rotor rpm's.

With that being said according to Magnuson you could turn it 7200 engine rpm's with a 2.8 pulley.

Many people have turned these engines past 7k with and without the addition of just rod bolts. I suggest rod bolts.

 

You are right about it being well past its torque range, but a cam will help out a ton on the top end.

 

Gadget, thanks for taking the time. Looks like with my current 3.2" I am well below max rotor RPM. I think I'll give it a shot and see if I get any more wheel speed this weekend.

Atomic, thanks for the reply. I am looking forward to the upgrades next year.

 

For around $300 you can get a used GT2-3 and some LS6 springs, why wait?

 

I've got an 06 5.3 (stronger internals) and I spin it up to ~6800 every time I drive it for over a year. Never had any problems.

 

Atomic, I have Comp 918 springs in it. Those will work well with the Gt2-3, wont they?

00 Thanks for the reply. I feel more confident in trying it now!

 

Yes, those will work. the GT2-3 has a max lift of .578 with 1.7 rockers

 

I'm not sure where my peak hp/tq is beacuase I maxed my Walbro 190 LPH out on the dyno at 4800-5000 RPMs. I immediatly swapped to a 255 LPH, but didn't have time to take it back to the dyno.

If you had to guess, what range would you expect it to be in?

 

Atomic I just noticed you are in Al. The mud ride I'm going to this Sat. is between Woodland and Weedowee Al. I just assume everyone on here is from Ca. That seems to be where everything is, well maybe Tx. too.