6 psi, but no real power increase - Miata Turbo Forum - Boost cars, acquire cats.

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Old 06-07-2008, 11:36 AM   #1
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Default 6 psi, but no real power increase

Okay guys, I installed the basic Jackson racing supercharger kit on my 92 1.6
-I own a turbo Miata and just wanted to try something different, In my opinion a turbo is superior to a supercharger, but I just wanted to do something else after four turbo cars. Here is my problem. I bought the kit used. My boost gauge shows 6 psi of boost(like it should) but I don't really experience a noticeable increase in power even at full boost. My first guess is that I am not getting enough fuel. I checked the hoses going to the AFPR and they are all hooked up right and are not kinked. I put a gauge on the vacuum line going to the AFPR and it is getting six psi of pressure at full boost like it should be. I haven't noticed any detonation, but I have been running high octane fuel. The car has 107K. I did buy a new fuel filter but have not installed it yet. My question is this. What else could it be? I checked all my connections and they are all tight, so I don't think I've got a boost leak anywhere. How do I check the fuel pressure to make sure that it is increases under boost. Any advice for a misguided guy?
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Old 06-07-2008, 11:43 AM   #2
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borrow a WB02 from one of the turbo cars to verify fueling?
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Old 06-07-2008, 11:47 AM   #3
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wow, toughie. if you have retarded your timing a ton it's not going to feel very fast. what about the bypass valve? it could not be opening, or could be backwards? the wide part should be closest to the SC, skinnier part towards the dummy throttle. what are you doing for timing control? I recommend a bipes, it ran my jrsc pretty well.
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Old 06-07-2008, 11:52 AM   #4
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Quote:
Originally Posted by tronik View Post
wow, toughie. if you have retarded your timing a ton it's not going to feel very fast. what about the bypass valve? it could not be opening, or could be backwards? the wide part should be closest to the SC, skinnier part towards the dummy throttle. what are you doing for timing control? I recommend a bipes, it ran my jrsc pretty well.
I have not retarded my timing at all. I've got really good high octane gas where I live and have never had a problem with detonation. As for the bypass valve, would my boost gauge show boost if that was the case?
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Old 06-07-2008, 12:03 PM   #5
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I think so - the bypass valve is what sends the boost to your intake manny (i think). it's also possible the little actuator arm on the JRSC unit, up near the real throttle body, has worn and isn't working properly. Rspeed sells a bracing kit for that arm for this reason.
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Old 06-07-2008, 12:09 PM   #6
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The actuator or arm is not the problem if you are seeing boost.
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Old 06-07-2008, 01:30 PM   #7
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I don't know anything about superchargers. If you are used to turbo chargers kicking in all of a sudden vs a supercharger basically pulling from bottom up. Are you just used to the power. I Drove my Zx9 all night thinking that the carbs are not performing right, just to figure out. I was used to 161 hp on the zx10 vs 40 less hp on the zx9.
But you should notice a differance between stock.
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Old 06-07-2008, 02:23 PM   #8
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well...I have been driving my LS1 camaro for awhile now and my butt dyno might be a little out of calibration, but I still think something isn't quite right about the miata
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Old 06-07-2008, 03:36 PM   #9
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fuel pressure with an afpr is directly related to boost.
you should run at 45 (base) + 6x6=36 psi off fuel..
That should be around 80 psi...
What's your FP??


Are you running an MSD/Bipes??

You could check the capped hose barb @ the end off the intake... It is used on automatics.. Sometimes the rubber is damaged, cousing a loss off air pressure @ boost, the hole is small enough to fully spool a turbo/supercharger to 6 psi...
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Old 06-07-2008, 03:42 PM   #10
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Quote:
Originally Posted by 92mazdarati View Post
well...I have been driving my LS1 camaro for awhile now and my butt dyno might be a little out of calibration, but I still think something isn't quite right about the miata
Its a 1.6 w/ a mp45 @ 6psi...

You should feel something though, thats quite strange.
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