Boost and gearing selection

I'm a little up in the air about my rearend gears. I know that it's needs a higher gear to load the turbo and so on. Right now i have 3.42s and I'm only 60ft'ing a 1.8x leaving in boost. It's still trapping 127-128. Raised the boost 2-3 lbs and same 60ft but trapping 131-133. Would gearing down help Or hurt me? All this is through an 80e and first gear is forever long. If the theory about wanting to be in the top of a gear still applies I should go down. Right now I trap in 3rd at like 5500. Ideas or suggestions?

what tire?

3.73 or play with the tire size

I had 4.10 and a 3600 stall and 4l60e when I was spraying and best 60' was 1.64. Now its a TH400 with 3.42s and a 3000 stall and on 11psi I cut a 1.63 60' but when I turned it up to 14psi it spun and cut a 1.77 60'. I dont think I would change the gears. Are you spinning or dead hooking? If its hooking maybe throw a 2 step on it and try to build some boost off the line. As long as the tires hold you should be able to cut some good 60'

im running a 30" tire right now and having the same problem as you. i generally get 1.70-1.75. i think its just the gearing for me. leaving on boost off the t brake and it launches hard as hell just doesnt get going quick enough. next time out ill be on a 28" tire and im betting that ill pick up a ton in the 60

28in tall tire. Doesnt show signs of spinning and doesn't feel like it. An 80e and lockup converter is a ton heavier rotating mass wise over a t400 setup. I never should of sold mine. But my cam is also a 242/244. So I think the motors unhappy. I'm leaving on 4-5 lbs

how quick does i get to full boost? what rpm you leaving at? suspension setup?

The 88 is sloowww. Prolly 30-40 feet to get all the way into boost. Usially Leaving 3300ish, stalls a 3000. Suspension is pure badass. Flip kit with leafs clamped, and q1a shocks..Ha. No wheel hop or any thing. It's transferring but just feels weak till a little bit. I have a go pro vid and it's about 40ft out and it'll take off

pt88??

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Originally Posted by sprayedenali

pt88??

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Yup

Yea my baby snail spools instantly, guess that's why it pulls so hard out the hole. Sound like gears wouldn't be a bad idea. 3.73s should still get you close to 145-150 depending on tire growth and rev limiter

Mine leaves out pretty hard and spools really fast with my 411's (haven't had time to put the 342' back in) but comparing my set up and yours is like apples and oranges.

Just keep cranking up the boost until the tires can't hold it. Bet you wont. Bitch

tire and gear combo sounds right.

sounds like the turbo just isn't coming in quick enough, you're not launching with enough boost, or you're not launching hard enough in the engines power band.
converter might need to be a little bit looser if you're launching around 3200rpms, i bet closer to 4k would help.
like my suspension guy said, "throw some damn power at it off the line"

the most common gear tire combo's are fairly close to what you have for example.
30" and 3.73
28" and 3.42
33" and 3.55
28" and 3.23

i've seen trucks with all those combos work really similar to one another.
4.10's seem to work well too.

probably not gear and tire related, and you said the rear suspension is fine.

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Originally Posted by farmtruc

probably not gear and tire related, and you said the rear suspension is fine.

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I believe he was practicing sarcasm. lol

sob lol, how you expect us to help then! :)

I've watched the truck and honestly, I think it just needs more power out of the hole. It hooks up well enough as is, so throw more power at it. It just doesn't come into boost soon enough.

I need to move the battery and fuel cell and lots more. It's far from a dedicated track setup trust me. So what about the rpms crossing the lines. Does the theory of crossing at highest rpm possible in that gear not apply to boost? I'm not ready to just turn it up yet devin lol. What about a two step or launch limiter or something? The stall is about as high as I can get on it.

im not a fan of the pt88 by any means, but i doubt youre just going to go throw a new turbo on it so ill just leave that alone.
but essentially, IMO, your problem is that its jsut not making the power and torque to make you leave hard. so like Devin said, just crank up the boost off the line (how you go about doing that is another topic) and itll run like you want it to

no reason you shouldnt be leaving on 10+ psi with it ramping in to whatever your max boost is almost instantly (within a second or so)

Wheels spinning in the tires? If those tires aren't screwed to the rim or if you didn't use hi-tac, I'd bet money they're spinning on the rim with that heavy ass truck. We had the same tires on the trans am and had to screw them because they spun about 1.5" on the rim at launch. That's one place to look.

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Originally Posted by phantom405

Wheels spinning in the tires? If those tires aren't screwed to the rim or if you didn't use hi-tac, I'd bet money they're spinning on the rim with that heavy ass truck. We had the same tires on the trans am and had to screw them because they spun about 1.5" on the rim at launch. That's one place to look.

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Never thought of that. After 4lbs it starts pushing truck forward

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Originally Posted by ecld_07

Never thought of that. After 4lbs it starts pushing truck forward

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Transbrake or two step time

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Originally Posted by LQ9_Z71

Transbrake or two step time

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As slow as FLT is I'd get tranny back next year sometime maybe. And if I can get em to put it in

Jakes Performance brake FTW.... Maybe a little spray out of the hole to help it spool. Gear and tire setup is fine IMO. It just sounds like it doesn't have the power bite it needs to hit hard.

I want a t brake bad. But I doubt FLT would be happy bout tearing into thier tranny. Lol

what kinda of gears would be good if im running a 32.97" tall tire? i was thinking 3.88 or 4.10?

373 or 342

Depends on your power. 500 or less 4.10 over 500 3.73 imo

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Originally Posted by ecld_07

Depends on your power. 500 or less 4.10 over 500 3.73 imo

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I loved my 411's with boost.... but went back to the 342 since I put the th400 in. With the 342 and 3600 stall I'm cruising around 2800 rpm at 65mph.

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Originally Posted by ecld_07

28in tall tire. Doesnt show signs of spinning and doesn't feel like it. An 80e and lockup converter is a ton heavier rotating mass wise over a t400 setup. I never should of sold mine. But my cam is also a 242/244. So I think the motors unhappy. I'm leaving on 4-5 lbs

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You're spinning Shawn... watch in high def and look at the tires closely...

https://www.youtube.com/watch?v=9zrcWhfyafo

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Originally Posted by qwk_snd

You're spinning Shawn... watch in high def and look at the tires closely...

https://www.youtube.com/watch?v=9zrcWhfyafo

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Had to get it to 1080hd to see it but I guess I am, hadn't seen that before now

haha yea spinning the crap out of them. what is your suspension setup?

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Originally Posted by o2camaross

haha yea spinning the crap out of them. what is your suspension setup?

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What's your set up? I had some pretty bad wheel hop the other night.

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Originally Posted by o2camaross

haha yea spinning the crap out of them. what is your suspension setup?

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Flip kit and leafs clamped.. Nothing special

mine is shitty. Just a djm 4/6 drop with homemade traction bars and shitty drop shocks. Cut a 1.63 hooking on 11psi but spun to the 60' on 14psi and cut a 1.77 I need some shocks bad and to relocate the shocks in the rear

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Originally Posted by ecld_07

Flip kit and leafs clamped.. Nothing special

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Traction bars?
I think we can benefit from a good set of shocks all the way around

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Originally Posted by o2camaross

Traction bars?
I think we can benefit from a good set of shocks all the way around

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Had some at one time and didn't like it's ride or transfer. This is the same setup that's went 1.5x and tons of 1.6x 60s in the past

damn. what tires?

28x10x16 but those where nitrous hits

That's damn good. I remember you telling me that.