Throttle Body Sizes??

[Lexx]

I have been thinking about putting a larger throttle body on my VN V8. Car had a new cam done by previous owner ( unsure of specs, but definately not standard ), extractors, so called "sports exhaust", modified 185 memcal with knock sensor set up.
What I'd like to know is what size throttle body is standard for the VN V8?
What sizes may be available?
How big is too big for standard stroke??
( And no, I don't want to fork out the $$$ for twins!! lol )
Any advice or suggestions would be appreciated.

 

[NOGEN 3]

V6's had the 60mm, V8's had the 65mm. The aftermarket 1's u get r 70mm(60-65 bored and 70mm butterfly). I plan on getting 1 soon(ish) to get a bit more air in, but dont forget, the runners in the inlet manifold will only allow so much air thru any way! Hope this helps

 

[Lexx]

Thanks for the reply. Info much appreciated :yeah:

 

[cole trickle]

HI guy's long time reader first time poster,

I'm thinking of doing the same mods to mine, also having the standard manifold extrudehoned

here's a link with some interesting figures

http://autospeed.drive.com.au/cms/A_0622/article.html

Cheers Dalesy

 

[Lexx]

I've been looking about for the 70mm throttle bodies and noticed that everyone is selling them as VN to VS.
Anyone know why no one seems to mention the VT 5L throttle body? Is the VT one different. If so, how???

 

[big_al]

i was told the biggest throttle body on a stock manifold was 70mm, if not check out starr performance manifold for 5lt with there custom maf tube and air box.

 

[Benji...]

I've been looking about for the 70mm throttle bodies and noticed that everyone is selling them as VN to VS.
Anyone know why no one seems to mention the VT 5L throttle body? Is the VT one different. If so, how???

Thread Hi-Jacking seems to be rife but i will comment anyway, The VT sI and the VS sIII had a different throttle design to the older V8s. The throttle is still 65mm but has shrouding on either side of the butterfly to make the throttle application more linear. The TPS is also different from memory.
Changing to a bigger throttle will cause issues with the ECU tuning as its uses the TPS alot more for load measurement as well as the MAF.

 

[Lexx]

Changing to a bigger throttle will cause issues with the ECU tuning as its uses the TPS alot more for load measurement as well as the MAF.

Thanks for the info. My VN has a modified "195" memcal and knock sensor fitted. Don't the Delco computers "learn" and adjust as you drive though?

 

[Benji...]

They do have the ability to adapt to adjust for variations like altitude or tune of motor. What it needs to do this is read its two main load imputs (TPS and MAF) then compare with the EGO sensor and as well as air temp and coolant temp sensors to do this. Throw a wild card in the bunch then it doesnt know any better.

Really a trial & error thing but it can easily be fixed by having the ECU reprogramed to suit the new imputs.

 

[Lexx]

Does the VN have a MAF sensor?? I know of the MAP sensor and TPS.