40mm or 45mm TBs for 8V?

[setgti]

Given that the standard TB has 52mm and 35mm openings, giving about 31 cm^2 (ignoring obstructions), should I go for 40mm (50 cm^2) or 45mm (63cm^2) TBs? My EFI specialist thinks 45s but I think it is overkill.

[DarrenH]

all depends on the level of tune, or the planned level of tune. 45's on an otherwise standard 1.8 8v (i'm assuming) would reck low and midrange due to low overall gas speed)

[Sam_Rallye]

All depends on how good the mapper is too, my friend ran an
otherwise standard 1.6 16v peugeot engine on 45mm tb's and made
decent power and torque throughout the
range.
Edited by: Sam_Rallye

[madmk4]

40's im going for on a 1.8 8v

You dont need as big a throttle bodies as carbs, because fo the way they work.So that probally isnt as small as it sounds...

What sort of revs were you looking at pulling ?

[prof]

yamaha r1s have SU like pistons in the t-body must help the low rev/part throttle states a lot

[setgti]

40's im going for on a 1.8 8v

You dont need as big a throttle bodies as carbs, because fo the way they work.So that probally isnt as small as it sounds...

What sort of revs were you looking at pulling ?

Only 7000RPM with the hydros. I'm thinking 40s. That is still a HEAP of area when you multiply it by four.

[jaistanley]

The larger trottles will give a more 'on-off' feel to the trottle at very low openings, meaning traffic, so might not be appropriate for a daily driver.

Jai

[badger5]

4x45's on my old jetta were very driveable.

Wot other mods are on the engine?