You GReddy guys all should replace your wastegates
10-14-2007, 08:15 PM
#1
Boost Czar
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You GReddy guys all should replace your wastegates
this is Rappadan's boost curve. Upgraded to a wategate actuator off a 300zx twin turbo. it bolted right up but had to be extended an inch.
but as you can see it's probably the best spoolup I've ever seen on a Greddy kit. Stock motor, turbo tony DP, 3" exhaust, MBC no helper.
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10-15-2007, 08:46 AM
#5
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It's not so much the spool up, but i haven't seen any better on a MBC. but the way it holds boost and doesn't spike is a substantial difference.
On the same MBC preload he was spiking hard to 12psi and dropping to 8psi by redline. Such is very common with all the Greddy kits as you are well aware.
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10-15-2007, 11:54 AM
#6
Boost Pope
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Did he pull this actuator from a junkyard car, or is there a known source of reasonably-priced new wastegate actuators for these cars? The last of the 300ZXs came over in, what, '96? I'm a little hesitant about sticking a 12 year old actuator on the car.
I'm tempted to try out one of the wastegate actuators offered by ATP Turbo. While some creativity might be required in terms of mounting and attachment, they have a couple rated in the 12-14 PSI range. Actually, I'd prefer to keep the MBC and use one with a lower rating, so that my WI failsafe mechanism continues to work.
I'm tempted to try out one of the wastegate actuators offered by ATP Turbo. While some creativity might be required in terms of mounting and attachment, they have a couple rated in the 12-14 PSI range. Actually, I'd prefer to keep the MBC and use one with a lower rating, so that my WI failsafe mechanism continues to work.
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10-15-2007, 12:33 PM
#8
Boost Pope
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Yeah, the stock actuator is a PITA. With a TurboXS MBC and a smallish helper spring, I've gotten the system to be fairly stable between 10-12 PSI, however there is still a noticeable spike.
Actually, this particular unit at FM looks attractive. It's a Gerrett piece, not terribly expensive, has a straight threaded rod, and a low base boost point so that I can keep the failback to low boost mechanism I've built. The ones that Forge makes look really nice, but a tad pricey...
Actually, this particular unit at FM looks attractive. It's a Gerrett piece, not terribly expensive, has a straight threaded rod, and a low base boost point so that I can keep the failback to low boost mechanism I've built. The ones that Forge makes look really nice, but a tad pricey...
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10-15-2007, 01:05 PM
#10
http://www.flyinmiata.com/dealoftheday/index.php
Should be easily be able to make this work .... $30, the price is right.
Should be easily be able to make this work .... $30, the price is right.
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10-15-2007, 01:05 PM
#11
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Probably, but I want something with a lower base pressure. My water injection system has a failsafe mechanism such that whenever there is no pressure in the waterline at the injector, a solenoid is open which bypasses the MBC. This way if the system ever fails, the turbo will make no more than base boost. With the stock Greddy actuator, this used to be 5PSI. Adding the helper spring increased it to about 8. I want to go back to something with a lower base boost to regain some of that functionality "just in case."
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10-15-2007, 01:56 PM
#12
Boost Pope
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... And interestingly, the FM Deal of the Day is this wastegate actuator: http://www.flyinmiata.com/dealoftheday/index.php
Looks perfect except for that oddball rod. Wonder how hard it'd be to modify that...
Looks perfect except for that oddball rod. Wonder how hard it'd be to modify that...
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10-15-2007, 02:42 PM
#15
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You can extend or shorten any rod by cutting it and tapping the ends and using threaded joiners. If it needs to be longer just get a piece of rod that is the same diameter. Also, if it's too long you can just use short lengths of tubing to shim the mounting bracket. I've done this **** a few times.
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10-15-2007, 02:58 PM
#16
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Personally, I have no FM hatred. Unfortunately, I also have no die set that I can use to thread that rod.
I think I may buy the other one, with the pre-threaded rod and the studs to attach a mounting bracket.
I think I may buy the other one, with the pre-threaded rod and the studs to attach a mounting bracket.
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10-15-2007, 03:15 PM
#17
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Aw, hell. I broke down and ordered the DOTD wastegate. I can't pass up $30. The money saved lets me go to Harbor Freight and purchase a proper Tap & Die set. 
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