AEM + CTSC - Best fuel press reg?

[Hell-bent]

I am converting to an AEM EMS on the NSX and need to know what the best fuel pressure regulator is to use with this combo. Is there a preferred brand or model? I assume I need a 1:1 rising rate regulator but the regulator supplied with the CTSC is a different ratio. FWIW I will be using 550cc injectors.

Thanks

 

[ken sampson]

Gerry Johnson has one that i am using on my setup 1.1 I am using 750cc injectors and a TEC-3 programed by GJ. it is alsom to dial in you AF and timing any way you want and run as smooth as stock. his setup allows for TBW and it works great. Good luck with your setup.

 

[titaniumdave]

I am getting ready to do the same set up and my plan is to not use a regulator at all. The AEM has enough capacity to control the fuel without the need to vary the fuel pressure. My local tuner at Torque Freaks won't even tune with the regulator installed because it is so hard to work around the inaccuracy of the mechanical regulator when compared to the digital control of the AEM.

Comptech uses a RRFPR as a 'work around' to work with the stock ECU, all the patches like this, fuel pump voltage doubler and the MAP sensor voltage clamp should be removed and run a higher pressure/high volume fuel pump like a Walbrow(sp?).

 

[ScienceofSpeed]

Do not use the supplied FMU from Comptech, just keep your factory regulator in place on the fuel rail. By the way, I assume you have an early car if you're using the EMS. A good thing to look at will be to replace your factory fuel pump. We're starting to see quite a few of the factory pumps kick the bucket as they exceed their service life. A new pump will also be able to support the flow of the injectors you are using. We sell the complete kit here:
http://www.scienceofspeed.com/products/engine_performance_products/NSX/Walbro/

regards,
-- Chris

I am converting to an AEM EMS on the NSX and need to know what the best fuel pressure regulator is to use with this combo. Is there a preferred brand or model? I assume I need a 1:1 rising rate regulator but the regulator supplied with the CTSC is a different ratio. FWIW I will be using 550cc injectors.

Thanks

 

[Hell-bent]

Do not use the supplied FMU from Comptech, just keep your factory regulator in place on the fuel rail.

Thanks to both of you guys for the same answer. So I will remove the CT RRFPR and keep the stock reg on the fuel rail. I hope I still have all the stock parts

I agree that a new pump is a must! Any other EMS conversion tips out there?

 

[burbel]

Just as an aside, when I went with this setup I decided to replace the stock fuel pump with an aftermarket fuel pump (Walbro 255HP), and, since I didn't think the stock FPR return would handle the increased flow, opted to use an AEM 1:1 FPR. If you're looking to swap the pump, going with a more powerful pump wouldn't be a dificult change.

Also, going with an aftermarket FPR gave me an easy location to mount an analog fuel pressure gauge, if you're into that sort of thing.

 

[sjs]

I am getting ready to do the same set up and my plan is to not use a regulator at all. ...

Dave, I'm pretty sure you don't mean what that says. You must use a fuel pressure regulator. If you don't, you are running full pump pressure to the injectors, but the AEM doesn't know what that pressure is and it won't stay constant. The ECU doesn‘t regulate pressure, it just varies how long the injector stays open based on various maps and trims, but those are based on a constant or at least predictable pressure. I think what your tuner means is what the others are saying, remove the additional RRFPR used by the CTSC and use just the stock or an aftermarket 1:1 unit. (still technically rising rate but for a net effect of zero). Point being to maintain a constant net pressure to the injectors so the AEM can accurately calculate duty cycle from the maps.

I favor the AEM regulator that bolts in the stock location, is adjustable for base pressure, and comes with several return orifice sizes. As also mentioned above, if you go with a higher capacity/pressure pump you may overwhelm the stock regulator return, hence the orifices with the AEM. I think it is the perfect choice for a CTSC/AEM system.

 

[titaniumdave]

Dave, I'm pretty sure you don't mean what that says. You must use a fuel pressure regulator. If you don't, you are running full pump pressure to the injectors, but the AEM doesn't know what that pressure is and it won't stay constant. The ECU doesn‘t regulate pressure, it just varies how long the injector stays open based on various maps and trims, but those are based on a constant or at least predictable pressure .

What I meant to say is a no variable regulator. The fuel pressure needs to be constant as you have stated, the ECU will only need to deal with the duration of the time the injector is on, not dealing with the variable pressure the stock RRFPR creates. Thanks for clarifing sjs.

Any reason not to use the Comptech RRFPR and disconnect the vacuum line? There is a base pressure adjustment which could be set an any pressure, plus there is no doubt the return line will be big enough and it is already installed on the car.

 

[burbel]

Actually, I'm not sure that the return is sufficient on the Comptech unit, since they have it configured to run with the stock fuel pump. Also, the AEM FPR is less than 1/2 the size (and lighter, too).

I'm not sure how the vacuum line on the FPR works, but I know that the AEM 1:1 has a vacuum line attached as well. Without the vacuum line, would it still be 1:1? Or would it be a flat ratio? Or would it decrease as revs rose?

 

[ScienceofSpeed]

The regulator would see atmosphere or the same condition under WOT and would allow the same maximum pressure as WOT under all throttle conditions. You'll need that vacuum line in place.

Hell-bent - it may be a good idea to check the health of the rest of your fuel system - fuel filter comes to mind if it has not been changed recently.

Cheers,
-- Chris

Actually, I'm not sure that the return is sufficient on the Comptech unit, since they have it configured to run with the stock fuel pump. Also, the AEM FPR is less than 1/2 the size (and lighter, too).

I'm not sure how the vacuum line on the FPR works, but I know that the AEM 1:1 has a vacuum line attached as well. Without the vacuum line, would it still be 1:1? Or would it be a flat ratio? Or would it decrease as revs rose?

 

[makena88]

Do not use the supplied FMU from Comptech, just keep your factory regulator in place on the fuel rail. By the way, I assume you have an early car if you're using the EMS. A good thing to look at will be to replace your factory fuel pump. We're starting to see quite a few of the factory pumps kick the bucket as they exceed their service life. A new pump will also be able to support the flow of the injectors you are using. We sell the complete kit here:
http://www.scienceofspeed.com/products/engine_performance_products/NSX/Walbro/

regards,
-- Chris

So what if I used the supplied FMU from Comptech? Will the AEM not function properly?

 

[sjs]

So what if I used the supplied FMU from Comptech? Will the AEM not function properly?

You could do that, but it would be a bad idea. For starters, the fuel maps would look really bizarre, appearing not to add fuel as load(boost) increases because the increased fuel pressure is adding the fuel instead. Tuning the AEM maps to account for that would be a huge pain and not allow for using some of the extrapolation features to create the initial maps. Even if you thought that was OK, I wouldn’t expect the shape/curve of the rising pressure to be extremely accurate/consistent which means less accuracy in fuel delivery. No, you don’t want to do that even though you “could”

As for leaving it there but without the vacuum line, I agree that’s a bad idea too, but it would be much more manageable than with the line connected. Capped so that even barometric pressure doesn’t effect it , it would probably maintain a constant rail pressure, which as Chris said would be equal to zero boost zero vacuum on the CTSC, or roughly WOT on an NA car. However, the maps would beed to be adjusted in the opposite manner of the other scenario, appearing to require more fuel than calculations might indicate because constant rail pressure means lower effective pressure as the injector tries to piss into the wind (boost), hence the desired 1:1 increase slope of “normal” regulators.

 

[spdntckt]

Couldnt he just remove the pressure sensor tube from the CT RRFPR and block it off? that way the pressure will stay constant no matter what the intake boost.. seems the unit will work fine in this fashion and just keep a nice constant base pressure..

 

[01blacks4]

Couldnt he just remove the pressure sensor tube from the CT RRFPR and block it off? that way the pressure will stay constant no matter what the intake boost.. seems the unit will work fine in this fashion and just keep a nice constant base pressure..

sure he could..but being that a new FPR is only about 200 bucks...and he is spending atleast 2K for the AEM and tuning...why not just do it right?

 

[sjs]

Couldnt he just remove the pressure sensor tube from the CT RRFPR and block it off? ...

Refer to the second paragraph of my prior post, that's what I was describing. You lose "effective" pressure, but if the base is high enough you can certainly tune for it. But again, why not do it right?

 

[ken sampson]

I was not going to use a 1:1 at first and i have 750cc injectors however it is much easier to tune with the rising rate. Question can the AEM do the same things as the TEC-3 like TBW,VTEC at various RPM if so is anyone running the VTEC at a earlier RPM?

 

[WOODY]

no tbw with aem :frown:

 

[maynard]

Has anyone heard when aem will work with tbw?

 

[burbel]

If you want to check out info on the AEM, I'd recommend hitting aempower.com, register and check through their forums. Most good AEM info can be found there, and there are some folks more experienced in tuning that can offer good advice.

As for the FPR, I think I got mine for under $100 from a parts shop in LA (the state, not the city). But I bought a lot from them; my injectors, fuel pump, FPR, AEM, etc.,

 

[Hell-bent]

Am I overlooking something basic? My CTSC has new fuel rails without the provision for a FPR. How am I supposed to mount the AEM unit in the car?

 

[titaniumdave]

Am I overlooking something basic? My CTSC has new fuel rails without the provision for a FPR. How am I supposed to mount the AEM unit in the car?

At the end of the fuel rail, replace the CT RRFPR with the AEM. Should be able to use the same lines and mount it to the body like the CT unit.

 

[Hell-bent]

At the end of the fuel rail, replace the CT RRFPR with the AEM. Should be able to use the same lines and mount it to the body like the CT unit.

This is where I went wrong. I wanted to use the NSX specific FPR that AEM makes but I guess I will have to use a universal one :frown:

 

[mikeh]

Question can the AEM do the same things as the TEC-3 like TBW,VTEC at various RPM if so is anyone running the VTEC at a earlier RPM?

I have the VTEC options in my ems configured to engage at 4500rpm. With my current setup, any later and I get a dip in hp/torque until it engages.

I'm also using the oem regulator, and letting the main fuel relay (not bypassed) control the voltage to the 255L/hr pump with 550cc injectors. I've had no fuel system issues. (besides running rich over 6k rpm.. can tune that out though!)

-mike

 

[sjs]

This is where I went wrong. I wanted to use the NSX specific FPR that AEM makes but I guess I will have to use a universal one :frown:

Yea, sorry, I wasn't thinking about the CT rails. They really weren’t necessary for such a low boost system but I guess people think they look nice and help justify the price. As mentioned, the AEM "universal" regulator can be used in place of the RRFRP, as could other generic ones. The AEM comes tapped for -6 AN fittings so you should be able to keep the same lines as the CT unit.

 

[car2n]

Do not use the supplied FMU from Comptech, just keep your factory regulator in place on the fuel rail. By the way, I assume you have an early car if you're using the EMS. A good thing to look at will be to replace your factory fuel pump. We're starting to see quite a few of the factory pumps kick the bucket as they exceed their service life. A new pump will also be able to support the flow of the injectors you are using. We sell the complete kit here:
http://www.scienceofspeed.com/products/engine_performance_products/NSX/Walbro/

regards,
-- Chris

I have the CTSC w/RRFPR, and what I believe is the FMU supplied with SC, , I have installed an external Automotive Tsunami fuel pump, pump relay is bypassed FP working from the FMU, if I get AEM EMS and AEM dual wideband do I have to remove these items and install 1:1 FPR, removed the FMU and re-connect the fuel pump relay?