65mm-70mm tb
- Thread starter mace6
- Start date
Black95GTS
Active Member
Your street heat manifold is already setup to accept a 75mm TB... I would go with that. The extra size will not hurt you, and as you continue to build up your car will only enhance the affects of other mods.
75mm. Are you converting to fox style or keeping it sn95 style? Reason I ask is because if your going fox style use an accufab, but if your keeping it sn95 I dont know what brand to recommend since accufab doesn't make TB's for your years. I had an accufab 65mm then switch to an accufab 75mm.
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greenlantern
Member
IMO 75mm is too big. Bigger is not always better. Remmember that what your after here is velocity. 70mm is as big as you will ever need on the street. I've seen several tests done at the dyno shop where 65 was swapped for a 70mm and there was literally no difference in performance, so in this instance get the whichever one you get the best deal on.
Is it now?greenlantern said:
This is fuel injection. Not carburation. Velocity is "made" in the runners of the manifold, not the throttle body.
With most camshafts, you will lose an inch or so of vacuum at idle. No big deal. My car lost about 2 inches at idle, and it still runs fine. Unless you are putting a Pro-stock-like cam in the car, you'll be fine and vacuum loss will not be an issue.mace6 said:
Joe
greenlantern said:
My thoughts exactly...
A TB can almost be used as a tool for velocity...and what if the runners are to "big"...what velocity is made then...many different factors come into play...not one specific part...
A 75mm would be more ideal for a stroked or blown car...
By swapping just TB's on a h/c/i engine...you would lose some torque (low rpm throttle response) on the lower end of the rpm spectrum...at WOT...
65 or 70mm would be fine for YOUR application...
ARed1995GT
New Member
everytime i see a throttle body thread i check it and see what u have to say haha, whether its on here or corral.. ur always repping that 75mm tb, what would u suggest for my car?Grn92LX said:
Lets think about this a little bit...
I contend that velocity is created in the runners of the (long) runner intake manifold. Others contend that throttle bodies regulate velocity. If that was the case, then could you use a 60mm TB on a Vic. Jr. intake manifold on stock heads and it would run OK because the TB is creating the velocity?
Joe
I contend that velocity is created in the runners of the (long) runner intake manifold. Others contend that throttle bodies regulate velocity. If that was the case, then could you use a 60mm TB on a Vic. Jr. intake manifold on stock heads and it would run OK because the TB is creating the velocity?
Joe
Joes95GT said:
I was referring to HIS application...not a bottleneck (stock)...which actually flows fairly decently for stock...You can give or take the "velocity" theory...you just can't be GENERAL with a TB statement...
I never said the TB is the only way to regulate velocity...it is one of many engine components you can use...
And to the original poster...make sure you have a nice flowing MAF/calibrated for you injectors (24 or 30lbers)...
Mike - I enjoy being inferred as "stupid"
"Some" people make their analysis of what part to get by trying to be different than others...but "if it ain't broke...don't fix it"...their are simply just some personalities that like to go different and praise it without having any real back-up on either side...
Some people need to give suggestions for a particular setup and not so GENERAL...
David
greenlantern
Member
Agreed 5spd GT.
Installing too large a throttle body can hurt performance, particularly torque as will installing too large a carburetor. This is especially true when talking about natually aspirated cars. Turbocharged or supercharged cars make up for the torque loss by capitalizing on high rpm airflow. The last thing to remember about choosing a throttlebody is shouldn't be larger than your mass air meter. You want to create a funnel for the air, so the mass air meter and filter should be large and necking down to the throttlebody.
Installing too large a throttle body can hurt performance, particularly torque as will installing too large a carburetor. This is especially true when talking about natually aspirated cars. Turbocharged or supercharged cars make up for the torque loss by capitalizing on high rpm airflow. The last thing to remember about choosing a throttlebody is shouldn't be larger than your mass air meter. You want to create a funnel for the air, so the mass air meter and filter should be large and necking down to the throttlebody.
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