Single Turbo RX-7's Questions about all aspects of single turbo setups.

help turbo

Old 04-28-15, 08:16 PM
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help turbo

ok have my first turbo car fd rx7 with haltech ported comp ct3x turbo what is correct fuel pressure setting currently boost 17psi at 20psi seems to car seems to sputter
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Old 04-28-15, 10:07 PM
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i think it should be about 38-40psi base pressure + 1psi per boost your running (rising rate fuel pressure reg)?
so at 17 psi boost, fuel pressure should be about 55-57psi

im still putting together my single setup so thats just what I seem to remember I had read. Someone will correct that if im wrong
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Old 04-29-15, 12:51 PM
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20psi is low.

A rising rate fuel pressure regulator increases fuel pressure faster than boost pressure and is NOT what you want. Your fuel pressure regulator should be "boost referenced" which means that it maintains a constant pressure differential between the fuel system and the intake manifold.
I usually set the pressure to 43psi with the fuel pump energized and the engine off. When the engine is idling you would expect to see 38-40psi.
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Old 04-29-15, 02:53 PM
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ok with the engine off fuel pump on its set at 45psi like i said new to turbo i thought the car was sputtering but after watching vids of rotary turbo cars running on you tube i think its just doing the turbo wastegate thing i have a true boost system and after playing with it it went from 20 to 25 before it did what i thought was sputtering but i guess its just the boost thing if i shift when it makes that cracksound it keeps pulling till it hits 25 again does it sound about right
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Old 04-29-15, 03:03 PM
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Going by someone else's description,(yours in this case) is really hard to do. Ask three people to describe what it should run like, and you'll probably get three answers. Then feed those descriptions to three other people and they'll probably tell you there's nine different thing wrong with each of the cars. I hope the car is properly outfitted and tuned for 25psi. Just jacking up the boost is a recipe for disaster.
I'd suggest finding someone local with experience in these matters and have them evaluate your setup.

Last edited by Vicoor; 04-29-15 at 03:04 PM. Reason: Add a word
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Old 04-29-15, 04:59 PM
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for sure the guy i got it from said it was dyno at over 500hp then they set it 420 by turning off the aem true boost but trying to make an appointment to have car dyno and see where what its at and how safe i can turn it up it also has methanol inj i was just asking to see if fuel press was correct
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Old 04-30-15, 08:29 PM
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Does meth injection work at 17psi or only 20+?
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Old 05-01-15, 03:26 AM
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Originally Posted by junito1 View Post
Does meth injection work at 17psi or only 20+?
It'll work at 17psi. I had mine starting at 7psi and building with boost
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Old 05-01-15, 01:24 PM
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A lot depends on what the car was at when it was tuned. changing fuel pressure will change the tune a little bit.

typically when I tune cars, the first thing you do is remove the vacuum hose to the pressure regulator and set the fuel pressure. depending on how strong your fuel pump is I would set this between 40-43.5PSI. when you plug the vacuum line in the pressure should drop a little. If you are going to max out the fuel pump, I usually cheat the fuel pressure close to 40PSI with the vacuum hose disconnected.

Having methonal injection adds to your fuel delivery, so you need to ensure that you are mixing the water methonal or methonal only injection is correct otherwise this will effect your Air fuel ratio. All of this needs to be right for it to run excellent.
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Old 05-02-15, 06:26 AM
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i was looking at fuel pump gauge with car at idle its 50psi then put meth to start injecting at 7 and set the high at 25 question the second adjustment on the aem methanol is the second adjust full spray at that what ever i set... if i set max at say 20 will it stop spray at 20 or will it keep spraying or where should i set the second adjust i dont want to set max at say 30 never make that boost and never get full methanol i dont know the numbers im throwing out are just to try to gauge understand how that system works i have no instructions car is getting better tires brake loose and car is getting sideways on 3rd gear on boost
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Old 05-02-15, 10:21 AM
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Originally Posted by r100 repu View Post
i was looking at fuel pump gauge with car at idle its 50psi then put meth to start injecting at 7 and set the high at 25 question the second adjustment on the aem methanol is the second adjust full spray at that what ever i set... if i set max at say 20 will it stop spray at 20 or will it keep spraying or where should i set the second adjust i dont want to set max at say 30 never make that boost and never get full methanol i dont know the numbers im throwing out are just to try to gauge understand how that system works i have no instructions car is getting better tires brake loose and car is getting sideways on 3rd gear on boost


I can't recommend anything since the air fuel ratio is the tell all for if you have everything set right.

on water/meth injections typically the first dial is when the pump activates, the second dial is where the water/meth maxes at and then stays shooting max above that PSI.
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Old 05-02-15, 12:33 PM
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ok didnt know if kept on spray after your selected psi air fuel at full boost is 10.somewhere its under 12 for sure
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