springs and tb

[shawnxj]

so i'm dropping my head off to get rebuilt and the new springs put on tomorrow but can't decide if i should leave them at the 110# closed 220# open pressures or if i should cut the seats enough to drop them closer to stock. what's y'alls opinion? running the lunati 63501 cam

i'm also sending my tb to get bored out and i know most of y'all are running 62mm bores but since most of y'all are running smaller cams i was wondering if i should get it bored bigger? say 63 or 64 mm?

[SilverXJ]

I would go with the spring load Lunati recommends.

[FlyinRyan]

If you have a stroker I would recommend a 68mm TB. Through data logging and tuning I have found that the 62-64mm TB present a somewhat significant restriction on the intake system.

[SilverXJ]

A 68 mm throttle body is like $400.

[jsawduste]

If you have a stroker I would recommend a 68mm TB. Through data logging and tuning I have found that the 62-64mm TB present a somewhat significant restriction on the intake system.

Where does one find the 68mm TB ? Even at 400.00.

My search skills are lacking today........

[SilverXJ]

F&B throttle body: http://www.fbthrottlebodies.com/products.htm They might even have a 70mm version.
Painless: http://www.painlessperformance.com/webc ... ield=65301

http://www.naxja.org/forum/showthread.php?t=1088449

Other ideas: http://www.jeepstrokers.com/forum/viewt ... f=5&t=1960

[jsawduste]

Thanks Chris.
need to research this some more. But I must admit the F&B is attractive.

[shawnxj]

talked to lunati and they said those numbers would be fine and i think i'm going to get a mustang tb like dino did and try that out

[CobraMarty]

I have a 70mm F+B, it is sweet. No issues, bolts on, everything fits, needs a different silicone elbow to air filter, will need to bore open the manifold to match.

[shawnxj]

that's nice...i'm not paying $400 for a throttlebody

[FlyinRyan]

A 68 mm throttle body is like $400.

If you make a simple adapter out of aluminum stock you could mount a 4.7 V8 TB, which is 68mm and readily available for 40-60.00 used. The sensors are all the same, and the whole swap doesn't take much fabrication. If there was enough interest I could perhaps get my machinist to put some together .

It's an easy 10 hp (or more) that is there, you just need to eliminate the restriction. And yes, I verified that the TB was the issue time and time again, not the air filter, or the intake tube either (although CAI's designed around a stock 4.0 will start providing a slight restriction on a decently built stroker).

[Retlaw01XJ]

It's an easy 10 hp (or more) ......

Ryan, at what rpm do you start seeing noticeable hp gains? Great tip on the 4.7 tb. I'll keep a eye out for one at the junkyard!

[shawnxj]

hmm good idea on the 4.8 tb i'll check the junk yard next week. i know i saw 1 last time i was there

[SilverXJ]

From what I have found the 4.7L Tb is only 65mm at the butterfly.

EDIT: http://thefastman.com/throttlebodies47.php

Looks like they went with a 68mm, but still is 3mm smaller due to a restriction, which should be easy to remove.

As far as the TPS and IAC are concerned, what is necessary to make it work? Looks like the throttle arm needs to be changed too.

[Muad'Dib]

The 4.7 Dakota TB i have has the part where you attach the cables adapted to fit in the Jeep. The other end for the TPS and IAC work fine even with RENIX Electronics (besides adapting TPS anyway).