I have an SRT 70mm T/B , and have it now on a JG V-X manifold , but want to go back to my ITR IM , can I adapt it for this 70 mm T/B ?

 

You can do your best to port match the manifold to the throttle body by boring out the plenum, but a better idea is to invest in a throttle body like the Spoon one. It's actually a modified OEM throttle body and is 70mm. It just bolts on.

 

what other mods to you have to need a 70mm TB? Unless you have a seriously worked motor, from what I have seen I think you are just wasting your money as you wont see much gain, if any, from just a larger TB especially on the stock IM.

 

motor B18C1 85mm 2.0 liter CR 12.8:1 , DTR 2.0l Header , Skunk2 stage II cams , 70mm should work , no ?

 

hahaha

sounds like a beast! Curious why you are going back to the stock IM over the JG? Im running the JG and 700 TB right now and am curious what would happen if I went back to stock with 70mm TB...be sure to post any results if you switch back to the stock IM.

 

This year I was running my JG Edlebrock V-X with the 70 mm T/B , but I read every where that this Victory X IM looses power on a N/A motor in midrange . Now I am building this 2.0liter engine , I realy want the engine to be strong in the midrange . Now I also read that the Vicory X will make power when used with high compression ?
What should I do ?

 

well I wish I had easy and cheap access to a dyno so I could do some comparison, but nobody wants to help me out with some cheap dyno time just to compare on my set up. My set up isnt crazy, but is far from stock and might give a good comparison between the 2 IMs. My JG is actually ported slightly as well.

 

This year I was running the Edlebrock IM on a B18C5 engine. STD compression.
I was thinking to go back to the stock ITR IM , because I was thinking of a good midange power on my 2.0 liter (with B16A head).

 

Wouldnt an aftermarket cam be more beneficial for making midrange? And I know that with my JG IM, it certainly didnt restrict power and Im able to make power upto and even past 9K rpm. I just wish I could compare with the stock IM

 

I have the Skunkstage II cams , I Use my car for trackracing , so I want to car to run strong in the midrange aswell.

On my std B18C5 engine (with the SK cams) the car was going like a rocket from 7.500 rpm to 9.500 rpm , hopfully I will go strong from 5.000 rpm to 9.000 rpm with this 2.0 liter now ?

 

nice motor...be carefull, I know a few people that cracked their B20 cylinders. Especially w/ a CR of 12:1. Unless your sleeved.
Anyway...The real thing to do is to remove the IM, and have a machine shop open it up to the 70mm. But the cheaper way is to stuff a bunch of rags down the IM and dremel it out. That's what I did. Worked fine. Just use a vacuum at the end, just in case.

 

well he has a B18C1 block so witha bore of 85mm it has to be a sleeved block.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99ITR#3715 &raquo;</TD></TR><TR><TD CLASS="quote">well he has a B18C1 block so witha bore of 85mm it has to be a sleeved block.</TD></TR></TABLE>

Either that or he's nuts (which is fine too).

It sounds like a bad *** motor though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dc231 &raquo;</TD></TR><TR><TD CLASS="quote">You can do your best to port match the manifold to the throttle body by boring out the plenum, but a better idea is to invest in a throttle body like the Spoon one. It's actually a modified OEM throttle body and is 70mm. It just bolts on.</TD></TR></TABLE>


Popular misconception there. Spoon tb is actually stock bore at the plenum. It is taper bored from something like 68mm though, but ultimately it's just stock diameter at it's smallest opening. And it's pretty much a waste of $ unless you don't have a tb at all in the first place.....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">Popular misconception there. Spoon tb is actually stock bore at the plenum. It is taper bored from something like 68mm though, but ultimately it's just stock diameter at it's smallest opening. And it's pretty much a waste of $ unless you don't have a tb at all in the first place..... </TD></TR></TABLE>

I was under the impression that by tapering the throttle body from 70mm (the inside diameter of the Spoon throttle body at it's largest point) you created less distortion in the airflow than you would with one that isn't due to the inside diameter of the outer side of the throttle body being equal to the size of the intake piping and the inside diameter of the inner side of the throttle body being equal to the diameter of the intake manifold. And less distortion of the airflow results in more horsepower. Naturally this theory depends upon the intake you use, but if you think about it, there is logic to it.

Either that or I'm suffering from lack of sleep and my posts are starting to show it.

 

I understand what you're saying, and it does make sense common-sensically.

But in reality (dyno'd), there are no such real world gains.

 

I have a spoon tb for sale

 

price?

 

OK, but should I leave my STR 70mm T/B on the Edlebrock , now I have higer compression ? Yes its an AEBS closed deck 85 mm sleeved block .

 

I dynoed my 85mm Toda 'D' beast with a 70mm throttle body and stock ITR IM (port matched to TB). Then I went back to the dyno with a JG VictorX IM and a 74mm TB. Lost a few hp in the mid-range and gained a couple up top. And the power peak moved up about 500 rpm. I don't have scanner, but perhaps C_A_T could post my graphs...? I liked the graph with the ITR IM and 70mm TB better.

 

Hi,

So my first idea should be right to go for the ITR IM + 70mm T/B , should give me some more power in the midrange , what nubers are you talking ?

 

This is the chart with the ITR IM and 70mm TB.

 

Most of the large after market TB's have a taper to them usually 2mm.
It tapers slow from the intake side(large) to the IM side (small).
But on the Spoon it is 70mm at the intake side but only tapers down
to the throttle plate(stock 64mm I think) and holds that size to the IM.

As for the original question I think I would run the ITR manifold with the STR tb.
I personally would port the manifold. When you do the tb port be carefully not to over do it.

 

wow, why did the torque curve sudden took a downfall??

 

nice numbers !!