70 mm TB? or smaller
Thread Starter
Joined: Apr 2003
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From: Somerset, NJ, US
70 mm TB? or smaller
So I built this all motor setup, overlooked a small detail. I did not shim the valve springs. It ran for about 100 miles then floated a valve at about 8000 rpm. It had catastrophic results. So now that i am ready to build it again, I have some extra cash and want a few more goodies. I would like a larget TB but I would like some opinions about this 70mm one. Does anybody think it is toooo much? If there is such a thing?
Thread Starter
Joined: Apr 2003
Posts: 37
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From: Somerset, NJ, US
Re: 70 mm TB? or smaller (cw98typer)
I am running a lightened eagle crank, with eage rods, 11.1 comp ratio, (it was cc by the machine shop, this is the exact ratio0) 10.5 lb flywheel and lightened crank pulley. The head is ported and polished, spoon valves, 3 angle valve job, crower 402a cams and matching springs and retainers. Skunk2 intake manifold, and RC 310cc injectors. Its a mean setup, Last time it ran VTEC was loud as a ****. Even though it ran like **** I could hear it would be quite fast. I just want to know if the larger TB would help me out at all.
Honda-Tech Member
Joined: Dec 2001
Posts: 3,643
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From: assville, MI, USA
Re: 70 mm TB? or smaller (Blk98Teg)
The correct throttle body size is based upon your intake manifold plenum size.
http://www.team-integra.net/sections...?ArticleID=471
The best way to find out if your TB is too small for your IM plenum is to determine what the intake manifold absolute pressure (MAP) sensor is reading (in the plenum) when you are at full throttle ( or wide open throttle (WOT) ) while the car is accelerating using a datalogger. The MAP should be equal to, or close to, atmospheric pressure. If it isn't or there is a MAP drop at WOT, then your TB is still too small.
The best way to find out if your TB is too small for your IM plenum is to determine what the intake manifold absolute pressure (MAP) sensor is reading (in the plenum) when you are at full throttle ( or wide open throttle (WOT) ) while the car is accelerating using a datalogger. The MAP should be equal to, or close to, atmospheric pressure. If it isn't or there is a MAP drop at WOT, then your TB is still too small.
Joined: Sep 2002
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From: Forget the penile implants, get a SVT
Re: 70 mm TB? or smaller (Blk98Teg)
totally O.T. But I am undertaking an engine rebuild and am wondering what you mean by shim the valve springs, what is that exactly?
BTW- 70mm is too big for an all motor setup in most cases. I think you would do fine with a 63MM TB
[Modified by Jiz101, 7:46 AM 4/7/2003]
BTW- 70mm is too big for an all motor setup in most cases. I think you would do fine with a 63MM TB
[Modified by Jiz101, 7:46 AM 4/7/2003]
Thread Starter
Joined: Apr 2003
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From: Somerset, NJ, US
Re: 70 mm TB? or smaller (Jiz101)
After the valve springs are installed the height of them must be meausred. They must be a certain length to apply the right amount of pressure to keep the valve closed at high RPMs. When shimming the springs, you are effectively compressing the spring and forcing it to aplly more pressure to the valve. A very expensive mistake I made, but hey, I gotta learn somehow.
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From: Starbucks Most, Likely
Re: 70 mm TB? or smaller (Blk98Teg)
Well, I got an ITR TB to match my Skunk2 IM's 62mm...however, you might want to get an ITR TB and have both your Skunk2 IM and ITR TB bored to 64mm....I didnt notice how aggressive your setup was however...mine is running awesome at 62mm...and I think I'll be making 215+ or so whp when I get my pistons in, and tuned. Then I might consider bumping them to 64mm...but for now...I am good.
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