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11.5-8-10 psi boost pattern? (buying a Texas car)

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Old 12-14-02, 10:44 PM
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94 FD, 69 Datsun Roadster

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Question 11.5-8-10 psi boost pattern? (buying a Texas car)

I tested a '94 FD with 44k miles today. It is bone stock, has a new factory motor, and 10k mile old turbos.

I followed the buyer's guide to a tee. Cold idled appropriately, no smoke, 5th gear ok, etc. The only odd thing was the boost pattern was 11.5 - 8 - 10 psi, with the dip at about 4500rpm. It was 68 degrees outside. Is this 11.5 psi ok, or does it signal a problem?

Also, the CEL goes on briefly when cruising. Code reads EGR. It has a 10k old EGR valve. A buddy mentioned that a backwards EGR valve gasket can do this.

Thanks for yo' help,
Chris
Old 12-14-02, 11:42 PM
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That pattern seems safe, although odd for stock. As long as boost doesn't hit above 12 or so psi, the stock ecu and fuel system should be able to handle it. I have no idea about the egr valve, so thats best left to someone with some more experience.
Old 12-15-02, 04:05 AM
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I get a similar pattern, ie a little higher than stock, even though I have absolutely no flow mods. The stock ecu has plenty of fuel for the extra 1.5psi, just make sure you never hit fuel cut. It could be the gauge too. This can, btw, be adjusted so you get something like 10.5-8-10.5, but its not really a big deal. Sounds like a healthy car.
Old 12-15-02, 10:22 AM
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Buy it. But remember that the car needs alot of Love.
Old 12-15-02, 05:24 PM
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are you sure it was 68 degrees outside, it been cooler than that here recently and I'm getting an extra pound of boost. what gear did you test it in? how much does he want?

BTW a texas car should not have code 16 for EGR, you my friend have a cali car

Last edited by gohorns; 12-15-02 at 05:26 PM.
Old 12-15-02, 08:43 PM
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That is a totally normal boost pattern. I've seen several cars that were stock or very close to it run a little more boost on the first turbo.

The important thing when looking at the boost "pattern" is that you get some significant boost above 4500rpm. Avoid buying a car (unless you can fix it) that has a 10-8-5 pattern. Low boost on the second turbo after transition is a bad thing. It is normal to have boost taper off by redline, usually to 6-8 psi.

jeff
Old 12-16-02, 01:54 AM
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try doing this if the owner allows it... to see if the egr is the problem that is. Use the howto on the egr elimination. its simple and is only two capped nipples. If you look at the x-over pipe by the abs pump, look down inbetween the pipe and the intake manifold and look for this stupid canister thing with some vacuum hoses around it. you will be able to see the hose leading from it to the intake manifold. this is the one you should use some caps on and see if it helps any b4 you buy it.
Ryker
Old 12-16-02, 02:18 PM
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Originally posted by gohorns

BTW a texas car should not have code 16 for EGR, you my friend have a cali car
Are you sure? I got a vehicle history report from Mazda and it shows that the car was sold from a TX dealership.

I'll try bypassing the EGR. Thanks everybody.

Chris
Old 12-16-02, 06:12 PM
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Originally posted by roadsterdoc


Are you sure? I got a vehicle history report from Mazda and it shows that the car was sold from a TX dealership.

I'll try bypassing the EGR. Thanks everybody.

Chris
Same here my car was sold from TX dealership but its got code 16 and also has the cali ecu. So to be 100% if your ecu starts with N3A3 then its a cali for sure.
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