What do you guys think is the best size throttle body for 98 XR8 which is the 185kw model.I thought they had a 65mm body on them but they only have the 60mm. I can get 65,70,75mm for the same price and i know i will have to modify the egr plate but what do you think will work best. It will have 1.72 rollers and a big maf meter with 3inch exhaust and standard EL GT headers, as well as 1inch manifold spacer and high flow airbox, car is an auto with 3.45 gears. Has anyone bolted throttle body on without egr plate and can it be done.
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EA Fairmont Ghia Turbo, White,425kw, nine inch, tremec, EB GT leather trim, B45 simmons, For Sale $16000
Stick with a 65mm tb, they are more than adequate for your set-up and will cope with most future modifications, with out loosing low rpm torque and throttle response.
They can be picked up second hand (with 65mmEGR) for about half the cost of a new tb.
You can also get the 60mm EGR spacer machined out for about $50.
What intake manifold do you have?
A 65mm TB will flow approx 690cfm, which is enough to spin a 5L to almost 8000rpm.
A 70mm TB fows approx 880cfm, which is far to much for a 5L.
Rick.
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4L I6, naturally aspirated producing 173.5rwkw.
14.410 @ 96.49mph with street radials.
What's that?..... Did I hear you say TQE power?
I'd agree, throttle bodies are a very overrated upgrade. 65mm is enough unless you're doing a stroker or something. Are you sure you don't already have a 65 on it? I swapped the stock one on my EF to one from an AU intake manifold and i'm pretty darn sure that's the one normally referred to as a 65..
definetly go the 65mm any bigger than you will sacrifice torque, this combo produes pretty good numbers on a stock 185, a bit of head work and you could get 230 - 240 rwhp,without going to overbored
Was thinking of running 70mm throttle body with only the 65mm egr plate behind it in case i decide to do furthur mods like a 347.The T3's had a 82mm body so i thought that a 70mm one might be good if i stroke it later. I am running the explorer manifold as thats what they came out with standard
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EA Fairmont Ghia Turbo, White,425kw, nine inch, tremec, EB GT leather trim, B45 simmons, For Sale $16000
I have the explorer intake and 65mm tb.
I would have thought this is what you would allread have?
I however had the EGR spacer machiened out to 70mm behind the 65mm tb to suit the Explorer opening, probably with no real performance advantage.
Try and pick up a 65mm tb with the EGR spacer.Or just machiene out the 60mm EGR to 65mm so as to keep the EGR valve mounted on the spacer,assuming you have the EGR valve.
I tapped a thread into the AU EGR spacer to mount my EGR valve despite it no longer being functional. .
Best to have an EGR spacer at least equal to your TB size, or at least file away the sharp edge a 60mm EGR spacer will have after a 65mm TB, or the 2.5mm lip on each side may impeed flow a bit.
Was thinking of running 70mm throttle body with only the 65mm egr plate behind it in case i decide to do furthur mods like a 347.The T3's had a 82mm body so i thought that a 70mm one might be good if i stroke it later. I am running the explorer manifold as thats what they came out with standard
82mm??? That's just a wank, at 8000rpm a 350ci motor only needs 800cfm.
A 82mm TB flows over 1400cfm.
A T3 would perform better with a 70mm TB.
Rick.
__________________
4L I6, naturally aspirated producing 173.5rwkw.
14.410 @ 96.49mph with street radials.
What's that?..... Did I hear you say TQE power?
Was thinking of running 70mm throttle body with only the 65mm egr plate behind it in case i decide to do furthur mods like a 347.The T3's had a 82mm body so i thought that a 70mm one might be good if i stroke it later. I am running the explorer manifold as thats what they came out with standard
If you are planning mods later on like a 347 or forced induction, a 70mm TB will be fine. I am running a 70mm on mine because at the time, they were out of 65's. I find it okay, just the throttle is a little touchy.
If you do go for the 70mm TB, use the correct EGR spacer. Going smaller will create a fair bit of turbulance. Matching 70mm EGR spacers are around $150 or you could try and open up the stock one.
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