Throttle Bodies - Single or twin ?

[71CALRIPPER]

I know this question cant have a simple answer but what are the pros and cons of having a twin throttle bodies on a flat 4 motor over a large single throttle bodie?
I know porsche and Scoobys tend to use single ones but can anybody shed some light as to why.

Turbo or N/A


Thank you for helping me with my search for knowledge
Roberto

[james wotton]

I used to have  twin 48 throttle bodies the down side I felt was you had to keep them them in  sync
I now have a single throttle bodie but due to it size (75mm) it's a bit of a on/off switch.

p.s may be twin's would be good for n/a but singel for turbo apllications.

james

[Martin]

Twin's give you a better throttle responce on a N/A motor, but are just a pain in the arse on a turbo motor. due to having to keep them in sync.

Pesonaly, if going for a hipo asperated motor, then a throttle per cylinder is the best way, instant response and you keep the throttle plate as close to the vavle as posible. There easy to keep in sync as you can just put your airflow guage strait onto them.

In the turbo aplication they also work great, but there just not so easy to keep in sync, as you have to remove all the pipwork to get a guage onto them.

Ive tried both ways and for me ive found the single throttle a lot less hassel. Ive gone for a 80mm throttle with a progressive linkage, its very smooth and transiant across the range.

Hope this helps

Martin

[warp]

You can run more cam using individual TB's and still have decent idle which I find to be a big advantage on a hot street engine.
...this is on a N/A engine

[Martin]

You can run more cam using individual TB's and still have decent idle which I find to be a big advantage on a hot street engine.
...this is on a N/A engine

Very True, my last motor, was 2915cc Fk98 cam 58mm throttle bodies and it would idle like a baby at 900 rpm.

[Jon]

About more cam, are you talking about separate runners or TBs ?

[warp]

I'm talking about individual TB's