62mm Plus TB`s

[FlyinRyan]

Is there interest in having a adapter made to bolt on a 4.7 TB?

[shawnxj]

i'm already having my machinist make 1...should be done with it tomorrow. was thinking about seeing if others wanted 1 as well

[jsawduste]

Count me in for an adapter.

[vashxj]

i was looking at that and wondering it the 4.7 tb spacer would overlap the holes on the intake, if so we can make our own adapters. i should be going out to the junk yard tomorrow i will see if i can find one and get some pics. depending on the weather that is, its supposed to rain/snow

[CobraMarty]

The adapter plate is the easy part, the linkage is more difficult.

[shawnxj]

the adapter my machinist is making will use a stock 4.0 gasket for the intake and a stock 4.7 throttle body gasket. i should get the part by wednesday and will post pictures....if anybody else is interested in them let me know

[shawnxj]

here's the prototype my machinist is making for me. i can already see a couple places where it will need to be trimmed



he sent me a cad drawing of what he wants it to look like when done after i tell him where to trim it down

[jsawduste]

Looks good. Keep us updated please.

[toypwr]

I'm right in the middle of doing my stroker build and was wondering if putting this large of a throttle body on a 4.6 would make the throttle touchy like people complain of with the 62-63mm bored bodies? I really like this concept and looks like a great piece he has machined out so far, any idea of what the end cost will be? I would like to upgrade my TB but not sure which way to go. My wife will be driving it sometimes and don't want any complaints, lol.

[Cheromaniac]

I'm right in the middle of doing my stroker build and was wondering if putting this large of a throttle body on a 4.6 would make the throttle touchy like people complain of with the 62-63mm bored bodies?

Mine's definitely touchy with a 65mm TB but I love it 99.99% of the time. The only time I don't is when trying to crawl offroad in 1st gear 'cause progress can be jerky.

[shawnxj]

he charged me $75 for mine not sure if he's going to stay with that price or drop it since now he has all the required measurements already programed. waiting on the finished adapter to come back since we had to make a couple changes to the first 1 i got then i'll post finished pictures and pics of it mounted up

[karl4x4]

Ok.. bare with me.
This whole thread is very logical. bigger hole=more flow. BUT anybody ever pinched the end of a garden hose? noticed the water speeds up and sprays much further...
now, what if this reduction of the throttle body was to keep the airflow speed at lower RPM to.. I don't know. Increase throttle response and torque.
I've looked for real technical info on this but couldn't find anything that satisfied my search for the truth.
I also know that when machining one of those throttle bodies, it is more work and more costly from the factory to create that slight funnel effect, therefore there must be a very good and reason every company and every year does that...

So I think bigger is not necessary better. Back to the garden hose principal. If it is too big, the water just falls to the ground. It would need a reducer to accelerate the water to go further.
Also, an engine's torque peak is directly linked to a mean exhaust flow velocity of 240 feet/second. To big of a pipe and you won't get that velocity until extremely high RPM if ever. Excelent article here: http://www.circletrack.com/enginetech/c ... ewall.html
Same should go for intake flow.


Anybody want to comment on this? Or maybe give me a link on some real technical data other than the usual "but feeling".

[SilverXJ]

The factory throttle body size and design was probably decided on by several factors. Ease of operation (linear throttle response w/ soft tip in), noise reduction, etc. In this case it wasn't decided on based on performance.

Take a look out what other engines around our displacement use. Jeep WJ 4.7L uses a 65 mm throttle body. Mustang 4.6L, 65mm. Just two.

As for the air speed velocity, while that might help with bottom end torque I don't think the theory holds up as when the air passes the throttle body it drops into a large open chamber, losing much velocity.

Our stock body is not a good fit for the strokers.

[Desertjr]

Ill be using a 80mm tapering to 75mm. 4.3l votec out of a blazer. I have it & a 59.5mm on my renix, so many people claim the 75mm will be huge and feel snappy. I don't understand what could be lost physically, in power or mileage...i guess 1 could argue velocity of the incoming charge..Most air through the smallest hole..and 75mm may flow more than my stroker will ever meed thus would have less velocity than a properly sized one? That would give less low end maybe cause the flow would be slow/lazy?
Wouldn't you gain mileage because less throttle position gives more opening from the bigger tb? I have a 5speed and personally I think it feels just right. Mileage never changed for me that was noteable on paper at least, although it sound louder intake wise at 50%-100% throttle. I dig it
I saw zero power or torque loss that I could physically feel. Felt touchy so to speak but not exaggerated and unwanted in my case. Top end felt stronger but I'm talking 4500-5200rpm. Could of been the sound gained that made it seem faster though,

http://www.cherokeetalk.com/forum/f64/t ... 70mm-6236/

Gonna bore my 99 style in take to 74mm or so, kinda keep the tapering effect going. And have an adapter cnc'd. I was running a renix intake with the stock 60mm bore. I was actually curious about that...maybe the 60mm bore on the intake manifold is the reason why it didn't feel slower down low? Because it helped keep velocity up?

[SilverXJ]

I seriously doubt you will lose mileage unless you constantly put your foot in it. Mileage will happen at a static opening anyhow. It may be a bit touchy, but you can get use to it. The top end is where you will definitely notice it.