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Throttle body spacing - Costs in power
AntonUK - 4/12/11 at 12:10 PM

Hi All,
I have a set of GSXR 750 throttle bodies on the way. I'm now musing over how to fit them to my silvertop

My intention was to use fatbaldbloke's sandwich plate design with my DCOE manifold... but...

But having seen this on ebay, I'm tempted to do this route instead.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230711708519&ssPageName=STRK%3AMESE%3AIT#ht_634wt_1110

I'm trying to weigh up the differences between the two atm. So has anyone got any info to the power loss by having corners in the inlet compared to the straight through design of the DCOE manifold?


dlatch - 4/12/11 at 01:01 PM

not seen any head to head comparisons of the re spaced bodies vs fastdans manifold
but any power differences will be marginal imo especially on a standard silvertop. have seen both setups produce great results.
if you don't have a Dcoe manifold already and have a set of unspaced gxsr bodies then the manifold you linked will make fitting by far the easiest solution, saying that re spacing the bodies is not hard to do


balidey - 4/12/11 at 01:16 PM

Basic rule of thumb, you want to have the smoothest flow as possible.
Looks to me like the ebay one has a couple of 45 deg mitre joints in two of the inlets. Common sense says to me thats not right.


will121 - 4/12/11 at 01:20 PM

cant say actual power differances but would always think straight is ulytimately best, but if you look at the standard manifold setup in a silvertop escort/fiesta it has plenty of bends.
another thing to considder if respacing is modified fuel rail as well, i fitted mine to a zetec sandwich plate and reused the standard zetec injectors like here

making a zetec manifold


big_wasa - 4/12/11 at 02:00 PM

Its a compromise either way with bike Tb's

Its a case of respacing the tb's so that they can all be ballanced and work as they should against un-equal length runners.

The second is the way the likes of bogg brothers do there carbs.


StevenB - 4/12/11 at 03:33 PM

Hi

There is a pic in my archive of my 750 GSXR TBs on a non
spaced manifold from Bogg Bros.

They said while there may be some benefit to be had
in re-spacing the bodies as I want my car for high days
and holidays it wouldnt really be worth it.

s


whitestu - 4/12/11 at 03:50 PM

I've had ZX6R carbs fitted both ways to the same engine and there wasn't any obvious difference.

Stu


AntonUK - 4/12/11 at 08:56 PM

Thanks all... Interesting reading...

I have the DCOE manifold already, and im quite happy to re-space the TB's if needed.

Just a matter of weighing up locost to getting more power