Supercharger Problem - Help
08-03-04, 01:22 AM
#28
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i've got a 6 port manifold built for a 4 bbl that i've been savin around for a drag car sometime down the road. i was thinkin all motor. after seeing this, i think supercharging is gonna be the way its gonna be. what kind of car did that M90 come off of? i know these things are everywhere lik the t-birds and XR-7 cougars but i was positive they were strait roots type, blowin into the intake manifold. am i wrong? or did you use the GM M90?
08-03-04, 07:31 AM
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The boost isn't going to 'rise' with RPM. It'll stay the same throughout the RPM band. If you're only getting 4psi, it's either because your pulley is too large, or you're leaking boost. But just remember, it's going to stay at whatever psi from 2k to redline.
08-03-04, 04:12 PM
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Originally Posted by SonicRaT
The boost isn't going to 'rise' with RPM. It'll stay the same throughout the RPM band. If you're only getting 4psi, it's either because your pulley is too large, or you're leaking boost. But just remember, it's going to stay at whatever psi from 2k to redline.
Last edited by miketreid; 08-03-04 at 04:14 PM.
08-03-04, 06:25 PM
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Originally Posted by miketreid
Thank you for the info. I guess it is time to get a smaller pulley
The stock pulley should be good for 6-9 psi of boost. I really think a leak or slipping is your problem.
08-03-04, 06:34 PM
#34
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Originally Posted by pyrojunkie
Bleh..
The stock pulley should be good for 6-9 psi of boost. I really think a leak or slipping is your problem.
The stock pulley should be good for 6-9 psi of boost. I really think a leak or slipping is your problem.
08-03-04, 07:18 PM
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You people need to stop thinking this is a supercoupe. It's not. It inhales different ammounts of air, thus the boost will be different if you retained the STOCK supercoupe pulleys. And since I doubt he's using the SC pulleys, then his pulley ratio is different from that of a supercoupe, so it wouldn't be the same even if he did have the same airflow as the thunderbird does. The easiest way to figure out what the problem is, would be to measure both pulleys, and post the results.
08-03-04, 07:24 PM
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Originally Posted by SonicRaT
You people need to stop thinking this is a supercoupe. It's not. It inhales different ammounts of air, thus the boost will be different if you retained the STOCK supercoupe pulleys. And since I doubt he's using the SC pulleys, then his pulley ratio is different from that of a supercoupe, so it wouldn't be the same even if he did have the same airflow as the thunderbird does. The easiest way to figure out what the problem is, would be to measure both pulleys, and post the results.
08-03-04, 07:46 PM
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The stock pulley on the SC, he doesn't really mention where he got the pulley on the crank from. Given his previous measurements, he's spinning it somewhere around 9-10krpm at 7k (engine) The boost leak is more than likely from that crazy bypass valve setup, but even then, it's still hard to figure out what he 'should' be at. That charger should be moving a hell of a lot more air at 10k rpm. But I can't be sure.
08-03-04, 08:50 PM
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Pulley sizes
Crank - 4.5"
Supercharger - 3.125"
Max spin on s/c I think at 7000 rpm would be 10,080 rpm
The smallest 6 rib pulley I can find for the supercharger is 2.7" and that would spin me up to 11,666 (I think)
Also I have presure tested the bypass setup and it did not leak, the valve might, but the pipe did not.
Supercharger - 3.125"
Max spin on s/c I think at 7000 rpm would be 10,080 rpm
The smallest 6 rib pulley I can find for the supercharger is 2.7" and that would spin me up to 11,666 (I think)
Also I have presure tested the bypass setup and it did not leak, the valve might, but the pipe did not.
Last edited by miketreid; 08-03-04 at 08:54 PM.
08-03-04, 10:42 PM
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The valve most likely does leak, it depends on how it's setup. That smaller pulley will give you almost 80-90cfm more. I think you'd see around 8psi with that size pulley through the band, as best as I can figure.
08-03-04, 11:07 PM
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Depends on the RPM. you figure it as a 2.6L, at a certain RPM and you'll generally be pretty close to what CFM it's sucking at that time. But it's still hard to say.
08-04-04, 04:39 PM
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I read something saying that the S5 N/A CFM is 370 @ 8,000 rpm. Is this correct?
Also if it is then 7,000 rpm should be 324 CFM. And if this is true, then my psi should be 4.6 if the supercharger is spinning at 10,080.
Also if it is then 7,000 rpm should be 324 CFM. And if this is true, then my psi should be 4.6 if the supercharger is spinning at 10,080.
08-05-04, 12:47 AM
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i was thinking of procharging my FC... what you recommend me do... so i dont go through the same problem you are goin through... and do i have to buy a new wire harness or anything?
08-05-04, 12:54 AM
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Oh man, if you have to ask questions that are that obvious and simple, you really aren't qualified to be supercharging, or turbocharging your engine. I suggest some massive heavy research, and at least a couple of years getting to know the car you've already got first.
08-05-04, 09:15 AM
#50
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. there is so much you need to find out about supercharging. you'll really have to research hard because theres not many people that have done it. its a really good power adder for the 6 ports because they usually dont have a whole lot of power down low which is where superchargers will really kick in.
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