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Upgraded throttle body


martybhoy

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Hey guys, has anyone upgraded their throttle body to the larger version commonly sold in the USA.

 

I have a friend in the states, who also has a zed, and we were discussing this mod.

 

It seems quite popular over there but I've not seen anything on here. Are the standard American throttle bodies different at all? Just wondering if I got one of the upgrades shipped over from the states if it would fit correctly tbh.

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  • 2 weeks later...

I doubt that you would see any real gains just by changing the throttle body, think of the restriction of air through the filter, the turbulance caused by the flexi part of the intake pipe, the coarse casting of the plenum & lower intake manifold, & then the size of the intake valves, their lift height & cam duration. Then there is the exhaust side.

 

So are you really going to achieve anything by solely changing the throttle body. No, save your money for some more petrol & tyres ;)

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The fact that Mark's graph shows a vaccuum in the plenum, presumably means the engine is sucking air from the plenum quicker than it can be replenished... showing the restriction is up stream of the plenum... so either the filter, associated pipework or maf... so bigger throttle body would make no difference until those other restrictions are corrected.

That's my take...

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All the reading I've done would indicate that it really isn't worth it unless you go FI

 

If your going FI a stock TB will flow 600+ bhp easily.

 

The dyno plots where using the vac take off from the front of the plenum.

 

It is strange that a car fitted with cams shows a little more vac than a car without so this leads me to there is a restriction somewhere but I dont think it is worth trying to remove the restriction like fitting cams to gain approx 10 bhp on a DE motor

Edited by Mark@Abbey m/s
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The fact that Mark's graph shows a vaccuum in the plenum, presumably means the engine is sucking air from the plenum quicker than it can be replenished... showing the restriction is up stream of the plenum... so either the filter, associated pipework or maf... so bigger throttle body would make no difference until those other restrictions are corrected.

That's my take...

 

totally agree with this. but is it worth trying to find the restiction

Edited by Mark@Abbey m/s
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On a healthy ukdm DE, prior to uprev what gains can be expected from bolt on breather mods? Ie exhaust, aftermarket panel filter, HFC and plenum spacer..... And of the above hardware, which do you rate in terms of bang for buck?

 

David

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On a healthy ukdm DE, prior to uprev what gains can be expected from bolt on breather mods? Ie exhaust, aftermarket panel filter, HFC and plenum spacer..... And of the above hardware, which do you rate in terms of bang for buck?

 

David

 

normally see around 250/255 hub bhp if you add HFC's or De-cat your see around 260/265 bhp which is just about 300bhp @ the flywheel, this is the best £ per bhp stage

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Neat!! In terms of peak power, on top of the above what bhp would be expected from an uprev and do you find its worth increasing the standard rev limit or not really?

 

That includes a Uprev remap the above figures

 

Not worth upping the rev limiter power normally rolled over at around 6800rpm

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Didn't fake Ben Taylor post some info on some testing done on the DE during a dyno run that reveled a big restriction through the plenum and throttle body?

That graph carries the info "DE 350Z_PLENUM,VELOCITY STACK,DE-CATS_UPREV" so there is definitely a restriction somewhere ahead of the plenum/throttle body, or even in the plenum?

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What Harry said, and a bigger tb on FI means the same airflow at less boost, since boost is only a measure of restriction :)

 

If theres a vacuum in the plenum it is indeed the engine sucking in more air than can get into it. This is everything that lets the air into the engine including the tb. I know from my research that the tb yields gains, a bigger inlet pipe yields gains (but needs ecu tweakibg to correct the maf readings) and removing the airbox and putting the filter in front of the rad yields gains - its all restrictive. All of it together with a remap can produce a much more reaponsive engine that can breathe easier.

 

This may not necessarily increase peak hp figures so no good for bragging rights but WILL create more room under the curve (though i know t will increase peak fivures also).

 

If the inlet system isnt restrictive, and there are no improvements to be made then why do itbs yield good gains? ;)

 

As Harry said, im creating tje same kit as NWP, just UK based and cheaper, theyve done the research and the benefits are on their website and googling it will show how much its liked in the states. Sasha Anis also tested bigger tbs and found they really help :)

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Surely just fitting a larger TB to the std plenum will defeat the object, as the plenum intake that the throttle bolts to will act as a restriction as its the same size as the std TB, also engine vacuum is a by product of the TB as its the metering for control of RPM, so there will always be a vacuum until the engines dynamic pumping ability limit is reached.

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