wastegate
Turbo Mini Forums

hi all this may sound quite stupid but what will I gain/ loose by adjusting my wastegate as its booked in for the rolling road on wensday, I have so much lag it's stupid haha

Do you mean adjusting the preload on the actuator? If so adjusting will cause the engine to run more or less boost so make sure that the engine will cope with what you set it to

Yeah the engines built to take a good 20 psi or so forged omegas stage 3 head etc if I adjust the preload will I loose a little bit of lag or not ?

That would depend on why you are getting lag, it will only help if the wastegate is opening before it should. But that is not really lag, thats it just bleeding off boost at lower levels than it should. If you put up specs of the engine and turbo and say what kind of rpm you normally get boost at people will be able to tell you if there is anything amiss with your set up or if you just have a laggy set up

its 1293 with omega 18cc dish slark stage 3 head kent turbo cam enlaged turbo elbow rebuilt t3 with 360 thrust std rockers and running lucas dizzy

thanks charlie

i think first of all we need to work out if your talking 'lag' or actual lag...

the correct definition of lag is how long the turbo takes to re-build boost whilst the engine is above the boost threshold after something like a gear change (or there abouts)

the incorrect use of 'lag' is when you nail the throttle and get no boost then wait...wait...wait...untill revs rise above the boost threshold and boost builds
people inccorectly call this lag for some gay reason,
when in reality either the turbo is too big and the boost threshold is too high or you are not using the engine correctly

the wastegate if it is working correctly in the first place would have no influence on either,
if it is fitted without enough pre load on the actuator spring the waste gate may open early and could make the turbo feel more 'laggy' or simply not build full boost
if it is fitted with too much pre load ( or more than recommended) the final boost figure will likely be higher


in short, adding more pre-load on the actuator may see you with more boost,
reducing lag would need a different more modern turbo and/or a complete intake redesign
lowering the boost threshold would need a smaller turbo/ bigger engine/ N2O / or alot of water injection

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Is the T3 a metro T3? What boost are you running and at what RPM are you making full boost?

Boost threshold can be improved in many ways. Increase CR, advance ignition, different turbo, manifold design, etc, etc.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

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Good post Brett.

If something is worth doing, it's worth doing half of.

Yes i moved to the darkside

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Thanks Brett think I may of not known the meaning behind lag (oops) and its a metro t3 and for the down pipe it is 2.25 and I've had a straight through powerflow 2.25 system made with no boxes or any thing , I'm only running the std actuator 4psi bled out to 9 psi it starts at 3.5kand full at just over 4 thanks Charlie

Yes i moved to the darkside

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That boost threshold sounds a little high to me for a standard t3 on a 1275. But as you have lower CR it probably makes some sense.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Good luck today mate. :)

well it did 121bhp with 0.6 bar boost but the fuelings way out :( at cruising its 0.68 lambda

Did they not adjust the fueling or was it just a straight power run?

They didn't have any spaces so I grabbed what I could and tweaked it a bit whilst there, lambda on boost was .87 and afr on idle is 14.5

And yeah light power run