Throttle Body

mac · Post by **mac** » Mon Jul 24, 2006 9:52 pm

Does anyone know the diameter of the standard fit alloy throttle body as found on the early S2's?

Cheers

Mac

Post by **ironside** » Tue Jul 25, 2006 2:08 am

I thought all the K engined plenum cars had 48mm ones, even the 160s. The 52mm one was an MGF thing.

Simon

Post by **simon** » Tue Jul 25, 2006 8:54 am

And I thought only the 111/111S had an alloy throttle body.

GregR · Post by **GregR** » Tue Jul 25, 2006 8:58 am

48 mill mac. Standard S1s had plastic to 1999-ish, and I'm guessing that they went standard 48mil alloy after that (as mine's got that). unless of course that was an aftermarket jobie ofc..

mac · Post by **mac** » Tue Jul 25, 2006 9:01 am

That's what I was thinking the answer would be.

It's interesting that PTP sell a 140 upgrade which comes with the alloy plenium and a 52mm TB - but their 165 kit comes with the alloy plenium but NO TB.

Just wondering if the bigger TB would help with my driveability issues at low speed.

Mac

Tom · Post by **Tom** » Tue Jul 25, 2006 9:53 am

mac wrote:
Just wondering if the bigger TB would help with my driveability issues at low speed.

Mac

TBH it's probably driver skill(or lack of)... A walshy day would sort that...

Post by **Shug** » Tue Jul 25, 2006 10:00 am

mac wrote:That's what I was thinking the answer would be.

It's interesting that PTP sell a 140 upgrade which comes with the alloy plenium and a 52mm TB - but their 165 kit comes with the alloy plenium but NO TB.

Just wondering if the bigger TB would help with my driveability issues at low speed.

Mac

Shyte - I was supposed to be digging out a TB for Mandy's car, wasn't I? TBH, I'd have to measure it, as I can't remember if it's 52 or 48mm......

The PTP still uses the MAP sensor, doesn't it? The engine might run a little lean with the 52mm TB, but shouldn't if the PTP uses MAP for fuelling as well as TPS.

If mine is a 52mm, you can always try it with no obligation to buy if it makes no difference

GregR · Post by **GregR** » Tue Jul 25, 2006 11:10 am

mac wrote:

Just wondering if the bigger TB would help with my driveability issues at low speed.

Mac

I'm getting worried about you mate - are you going soft in your old age?

man buys PTP 165, SportsCat, ITG, Nitrons, A048s and OZ wheels, ARB... then worries about "low speed driveability"

The_Rossatron · Post by **The_Rossatron** » Tue Jul 25, 2006 11:37 am

All S2's have a 48mm alloy throttle body if that helps.

mac · Post by **mac** » Tue Jul 25, 2006 12:00 pm

The_Rossatron wrote:All S2's have a 48mm alloy throttle body if that helps.

Ta. Shug if you can dust out that TB that would be great and if its a fix or improvement the I'm sure some beer tokens can be exchanged.

As for the issues - my car kangaroo's on part throttle, which ain't fun or pretty when on hard set nitrons.

Mac

mckeann · Post by **mckeann** » Tue Jul 25, 2006 1:05 pm

the bigger throttle body will make your drivability issues much much worse. Basically, for the same throttle opening at the peddle, the TB will flow more air, and the car will be even jerkier when just trying to manouvere slowly or in traffic jams.

Post by **Shug** » Tue Jul 25, 2006 1:11 pm

mckeann wrote:the bigger throttle body will make your drivability issues much much worse. Basically, for the same throttle opening at the peddle, the TB will flow more air, and the car will be even jerkier when just trying to manouvere slowly or in traffic jams.

Unless the slow speed mapping is overfuelling like a b'stard. Either it could do as you say, or the increased airflow will damp down the pulses from the bigger cams in the plenum and give the MAP sensor a more stable signal to work with.

It's worth a try, as the fuelling will be varied by MAP sensor as the PTP uses a piggyback ECU - so the MAP functions of the standard ECU are still trying to read pressure from a manifold that's now filling with pulses from the harier cams....

mac · Post by **mac** » Tue Jul 25, 2006 1:16 pm

as shug said

Mac

GregR · Post by **GregR** » Tue Jul 25, 2006 1:19 pm

pah - he always beats me to it

[awaits comic replacement of "off" for "to it"]

Post by **Shug** » Tue Jul 25, 2006 1:20 pm

mac wrote:as shug said

Mac

Just going by experience of running the 285H cam on a plenum for a wee bit. Even with the cam timing set very mild, it had to run waaaay rich to idle, and wasn't happy at low speed. I didn't try with & without the bigger TB, so coudn't say if there was a difference and the Emerald doesn't use the MAP sensor, so it wasn't trying to compensate.

Just a theory though