90mm Throttle-Body

**Naf** · 12-10-2006, 06:03 AM

Hello all,

Ok i am not acustomed to this section of LS1...But i have a HUGE problem...I am looking for a 90mm throttle body that is from the 2003-2006 era of Gm trucks...But it has to also has to fit the FAST LSx intake manifold...

I was thinkin of takin a BBk 80mm throttle-body Pn 1756 and portin it up to 90mm...Is this possible?

Your thoughts please...

**blue02Z** · 12-10-2006, 06:55 PM

doesnt FAST make a 90 mm tb?? and how do you have an '06 caprice??

**Naf** · 12-10-2006, 08:08 PM

FAST do make a 90 mm throttle-body, and so do alot of other companes, however they are all cable driven and not Fly-By Wire...

Well i wished really hard and a nice man brought one for me from Australia...Holden have the right to produce the Caprice for in the Middle East, they are hot sellin items...

The car looks like the Holden Statesman...Long chassis, and plenty of power...

**Phlash_riot** · 12-10-2006, 09:59 PM

not part of your question but can we see some pics of your car?

**Naf** · 12-10-2006, 10:09 PM

I aught to, but presently its in the shop, and she doesnt look very pretty...

i have attached some pics when i found her in the showroom...

I have done a few nice mods to her recently but i am cursed with incompadible parts...

By the way her name is Patricia

**blue02Z** · 12-11-2006, 04:05 AM

i didnt realize you have a fly-by-wire. what engine is in it?

**Naf** · 12-11-2006, 04:15 AM

Its an LS1...But we in the Middle East have different throttle controls...The throttle-body i have right now fits on Tahoes, Escalades, Luminas and Caprices...

I found out also that the BBK fits the FAST 90-mm LSX intake manifold...I just needed a Spacer to insure perfect fitment...

But the question still beacons, can i port a BBK 80-mm to a 90-mm Pn 1757, i messed up the first time...

**Phlash_riot** · 12-11-2006, 01:54 PM

I think it all depend on how much meat is on there. Also take into consideration that you may not need a 90mm on there. Depends on your mods. a 80mm might work just fine. Obviously if you have free flowing intake mani it can take advantage of it but the you have to figure out how my your cyl. heads can use that to thier advantage.

I am not saying that it will or won't but just posing to you that you might want to look at that beforee you go all out on something that you may not entirly need....unless you just want show and bragging rights.

**12secSS** · 12-11-2006, 03:45 PM

First off, there is no point in really doing that. The truck intake has an opening that is a meare 75mm in diameter, so you will still have the same restriction. The other issue is that if you port your throttle body any larger, you will need a new throttle blade. It needs to fit in perfectly, otherwise you will have idle issues. Just purchase any three bolt 90mm throttle body. The FAST has provisions to mount your stock, three bolt throttle body and has a four bolt pattern as well for aftermarket units.

**Naf** · 12-11-2006, 09:24 PM

Originally Posted by 12secSS

First off, there is no point in really doing that. The truck intake has an opening that is a meare 75mm in diameter, so you will still have the same restriction. The other issue is that if you port your throttle body any larger, you will need a new throttle blade. It needs to fit in perfectly, otherwise you will have idle issues. Just purchase any three bolt 90mm throttle body. The FAST has provisions to mount your stock, three bolt throttle body and has a four bolt pattern as well for aftermarket units.

Mommy, why is Little johnny not understandin,
Well Timmy, its cause he doesnt read very well...

If you were to scroll all the way up to the top you would see i need a fly-by-wire throttle body for a FAST intake that is usable on a 2003-2006 GM Truck...

One more time, electronic TB that will work on a GM truck, but will fit on a FAST 90mm intake....

**12secSS** · 12-12-2006, 08:01 AM

Originally Posted by Naf

Mommy, why is Little johnny not understandin,
Well Timmy, its cause he doesnt read very well...

And by your quote, I guess you don't read (nor write) very well either.

You will need a new throttle blade if you modify a stock OEM unit. You can however use an LS2 Throttle Body, as it is DBW. Plus, you are going to run into problems fitting up a FAST to a truck, as the throttle body will interfere with the water pump outlet and possibly the serpentine belt.

**shabysurf** · 12-14-2006, 01:00 PM

Dude, he doesn't have a truck, its a ls1 powered ? but he refered to truck, because of the way his tb is set up (from the middle east?) drive-by-wire.

**Naf** · 12-15-2006, 12:46 AM

Originally Posted by shabysurf

Dude, he doesn't have a truck, its a ls1 powered ? but he refered to truck, because of the way his tb is set up (from the middle east?) drive-by-wire.

We have a keeper here...

No worries, i got a BBK throttle body P/n 1757 and tapered the back end from 75mm to 85mm...Later when i have more confidence with the lathe i will port it out to 90mm...it has enough meat on it, i just need to figure out how to mimic the grooves...

**shabysurf** · 12-16-2006, 09:01 AM

hey does anyone know the largest size tb a truck maniflod can take
or are there any 90mm intake manifold for trucks, or would it be easier to install an electric fan, and put on a FAST manifold

**Naf** · 12-16-2006, 08:17 PM

The largest pushin all limits is 78mm...As for the FAST intake i would not advice it...The truck has long runners for torque...With the FAST you will gain Hp but lose on Torque...

Everyone seems to forget that you need torque to kick the other guys ass...

If you would like go for a LQ9 intake and a ported 78mm TB...

You wont lose on Torque, but you will gain on Hp...

**shabysurf** · 12-19-2006, 07:59 AM

I have a 5.3 (L33), is the intake manifold the same as the 6.0 (LQ9), and what tb size is that? 65mm?

**Naf** · 12-19-2006, 10:58 AM

Let me do some diggin and i will get back to you...

So far i know the 5.3 and 6.0 use the same throttlebody of 72mm, but there is enough space to squeeze in a 78mm...I Think the LQ9 intake flows a bit better then the LM7.

Kinda like the LS1 and LS6 intakes...

**shabysurf** · 12-19-2006, 01:20 PM

thanks

**whitez28onspray** · 12-23-2006, 09:19 PM

i think the 6.0 has an 80mm tb

**Naf** · 12-24-2006, 04:01 AM

Originally Posted by whitez28onspray

i think the 6.0 has an 80mm tb

Hehe, we all wish for then we can save a bundle wen swappin up...In reality, it is the same TB as the LM7...a small 72mm

check it out..go to a GM parts guy and ask for the PN for a LQ9 tb and a LM7 tb...they are exactly the same tb..funny eh, i would have thought it would be bigger...But alas the LS1 and LS6 are cursed with the same problem...

GM is too cheap to change out a good average part