evo 8 with fp green alchy boost tapering???
Aug 19, 2008, 07:29 PM
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evo 8 with fp green alchy boost tapering???
i have an evo 8 with an fp green and alchy.my boost is spiking to 29lbs,and tapering to 23 lbs. what can i do to hold the boost. i beleave i have the fp 18lb wastegate im not 100 percent sure?
Aug 19, 2008, 07:53 PM
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all the greens and stock turbos lose boost up top. Its normal and the only thing to do to help is find a rpm base boost controller to help a little but it will always taper! Ive tune a evo red from fp and the boost doesnt taper at all! with the boost controller we use!
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Aug 20, 2008, 05:37 AM
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Why don't you know whether your WGA is the stock unit or the FP HD WGA? Did you purchase the Green used? If you purchased it new, to have it fitted with the FP HD unit you would have had to pay $80.00 in addition to the base price of the Green turbo.
If you didn't order it specifically with the 18 PSI actuator, then chances are that your Green came with the stock Mitsubishi IX actuator. The stock IX actuator is a nice unit. All 16G actuators, VIII-IX, are adjustable, being that the actuator rod is threaded on the end.
Either way you should be able to set the wastegate preload to achieve the desired results. You didn't give us your complete modlist yet. Is your car equipped with an aftermarket O2 housing? Are you running a catalytic convertor?
It would be best to assure that you have the wastegate and boost control all functioning perfectly at normal, non-alky, boost levels before turning the wick up. My guess,as some others have already mentioned, is that you are running little if any wastegate preload. At least, I'd start there and set wastegate preload to just a couple of PSI below what your pumpgas peak boost level is.
If you switch back and forth between high boost(30 PSI, Alky), and low boost(21 #, etc.), then the wastegate preload level would have to be tailored to suit your pumpgas peak boost. If, however,you run strictly on Alky, then you can try setting wastegate preload up higher, around 21-24 PSI.
If you didn't order it specifically with the 18 PSI actuator, then chances are that your Green came with the stock Mitsubishi IX actuator. The stock IX actuator is a nice unit. All 16G actuators, VIII-IX, are adjustable, being that the actuator rod is threaded on the end.
Either way you should be able to set the wastegate preload to achieve the desired results. You didn't give us your complete modlist yet. Is your car equipped with an aftermarket O2 housing? Are you running a catalytic convertor?
It would be best to assure that you have the wastegate and boost control all functioning perfectly at normal, non-alky, boost levels before turning the wick up. My guess,as some others have already mentioned, is that you are running little if any wastegate preload. At least, I'd start there and set wastegate preload to just a couple of PSI below what your pumpgas peak boost level is.
If you switch back and forth between high boost(30 PSI, Alky), and low boost(21 #, etc.), then the wastegate preload level would have to be tailored to suit your pumpgas peak boost. If, however,you run strictly on Alky, then you can try setting wastegate preload up higher, around 21-24 PSI.
Last edited by sparky; Aug 20, 2008 at 06:47 AM.
Dec 9, 2008, 11:33 AM
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Did you fix your boost taper ?? iam on the same boat...I was tapering to 21psi now I added the Hks Evc6 and Iam able to hit 27psi and hold 23.5 psi at 7k.
I haven't adjusted it more but I don't want to push it.
(wastegate pressure is 26psi)
I haven't adjusted it more but I don't want to push it.
(wastegate pressure is 26psi)
Last edited by ROGERV; Dec 9, 2008 at 11:36 AM.
Dec 10, 2008, 04:32 AM
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The larger diameter Green's turbine wheel exducer blades are heavily shrouded within the turbine housing's discharge area as cast by MHI. This discharge area can be ported. This process when done correctly will help eliminate the Green's boost taper issues.
Through Bryan(Razorlab) at GST Motorsports, you can get in touch with the guy that does their turbo porting. His name is Steve. Maybe someone will chime in with his number.
Also, if you are running the stock metal DV, you can try crushing it.
Through Bryan(Razorlab) at GST Motorsports, you can get in touch with the guy that does their turbo porting. His name is Steve. Maybe someone will chime in with his number.
Also, if you are running the stock metal DV, you can try crushing it.
Last edited by hawa; Dec 10, 2008 at 04:49 AM.
