TB Size

[Superdave]

Currently running the TCE 65mm TB, seems that there could be some room for improvement in flow for my setup. I'm thinking about going to 70mm at the least, possibly to 75mm. Porting my plenum is no problem, I'd like to smooth out the inlet anyways..

Here is some of the specs i found out on the net, not for the TCE but i'd assume the numbers are very close..

ACCUFAB 65MM
TESTED @ 5" - 280 CFM
CORR @ 20" - 560 CFM
CORR @ 25" - 627 CFM
CORR @ 28" - 664 CFM

ACCUFAB 70MM
TESTED @ 5" - 332 CFM
CORR @ 20" - 664 CFM
CORR @ 25" - 744 CFM
CORR @ 28" - 787 CFM

ACCUFAB 75MM
TESTED @ 5" - 390 CFM
CORR @ 20" - 780 CFM
CORR @ 25" - 874 CFM
CORR @ 28" - 924 CFM

Ben, if you could flow one of those 65mm TB's it would be very helpfull as well.. just to see how close they are to the above numbers.

Opnions?

[PCGUY112887]

What ever happened to the whole "you won't be able to drive it correctly" thing?

[Superdave]

Some info i found...

http://www.cartechbooks.com/vstore/showdetl.cfm?DID=6&Product_ID=3048&CATID=21

One effect method of determining the worth of a throttle body, or any airflow restriction for that matter, is by monitoring the vacuum present behind the component. In the case of a throttle body, taking vacuum measurements at wide-open throttle from a source inside the intake manifold as close to the throttle body as possible gives you a good indication that a restriction is present. It takes an accurate vacuum gauge, preferably one that reads small changes, since you might be looking for 1 to 2 inch. The scale on your test gauge should read from 0 to 5 inches, and no boost. The typical vacuum/boost gauge will not likely be accurate enough unless the restrictions are sizable. If you record vacuum readings that exceed 2 inches at wide-open throttle, chances are a throttle body will be worth some power. If the vacuum reading is less than 1 inch, there isn’t much power to be had with a larger throttle body. The vacuum present behind the stock throttle body will increase with engine speed and power output. It’s a lot less expensive to check the vacuum than buy a throttle body only to find out the stock one is fine for your current power level.

I'll try that later on tonight...

[Superdave]

What ever happened to the whole "you won't be able to drive it correctly" thing?

What do you mean?


if the engine actually needs more flow then it won't hurt anything.. at WOT my MAP values are only hitting 92, that's why i started thinking i needed a bigger TB.

[whitelightnin04MC]

Dave, sell me your 65mm. I'm sitting here looking like a jerry's kid with this 62mm on my 3500 Upper.

[ForcedFirebird]

Some info i found...

http://www.cartechbooks.com/vstore/showdetl.cfm?DID=6&Product_ID=3048&CATID=21

I'll try that later on tonight...

Please do! Thanks for that tidbit of info, now it's time to experiment when the hybrid is running. I'm curious to see the results.

[IsaacHayes]

get the 3900 adapter and run a 4.3/5.3l TB 70mm.

[whitelightnin04MC]

get the 3900 adapter and run a 4.3/5.3l TB 70mm.

But Dave doesn't have a 3900 plenum to bolt the adapter to. Does the 3900 adapter work with the 3500 Upper?

[IsaacHayes]

I believe so. I think they were made to work on both. If 70mm is too small, then the N* TB is next step up at 75mm.

[Monzsta]

Dave, sell me your 65mm. I'm sitting here looking like a jerry's kid with this 62mm on my 3500 Upper.

Then sell ME your 62, so I don't look the same with a 55 on my 3400!

[SappySE107]

I can't flow 600+ CFM. My setup is for heads only, or heads with manifolds, etc. Until your tune is redone correctly (not tuning for WOT first, dyno that shows 30-50 hp changes withing 400 RPM), I wouldn't go throwing more parts at it. There is a lot more to that 92kpa than the TB size.

[IsaacHayes]

It certainly isn't is filter setup. It's crazy! haha

[Superdave]

I can't flow 600+ CFM. My setup is for heads only, or heads with manifolds, etc. Until your tune is redone correctly (not tuning for WOT first, dyno that shows 30-50 hp changes withing 400 RPM), I wouldn't go throwing more parts at it. There is a lot more to that 92kpa than the TB size.

I'll see if i can get one of the other runs scanned in, they aren't as bumpy the more we got the AFR's smoothed out. I did lose some power the leaner we took it. It still needs alot of work, I probably won't invest much more dyno time into it this year though.


I'm going to the track this Friday and that'll probably be it for the rest of the year.

[torq455]

isn't the stock TB size on a 430hp LS6 corvette engine 75mm? TPIS told my dad not to bother with their bigger TB's. why would you need that much?

[IsaacHayes]

430hp LS6? You mean the 2008 LS3? That's 430 hp. The LS6 was 405 hp in Z06 trim.