when should a fuel rail be need. i have a ams 30r evo9 and will be double pmpr, 1200s. will i be fine with stock rail or should i get a fuel rail ? i need some feedback base on some other peoples experiences.

 

The fuel rail was said to be fine left stock until you push the 600hp mark. I don't think the type of fuel matters.

 

The type of fuel DOES matter because you need much more E85 than gasoline to support the same power levels. The stock evo fuel rail is fine to max out 1000's and a single walbro pump with the bypass valve disabled. If you want to run bigger injectors than this a larger fuel rail can help to act like a water hammer to absorb the pressure transients when a large injector opens to let in a large amount of fuel. Thus the fuel pressure available for each injector is more even and consistent. The larger the internal volume of the fuel rail the better.

 

I think the way to know for sure would be if/when you upgrade fuel injectors and add the double pumper, and are still not able to meet the E85 fuel needs. You may need a larger fuel rail on E85 even if its not needed on the same setup using gasoline.

Anything over 1,200cc injectors ought to have an uprated fuel rail. Just my opinion, no science to back that up.

I'd say you are prolly OK with the stock fuel rail on the 30R. Now, when you go to the 42R and the 1,600cc injectors I'd say add a rail.

More food for thought: Thread by Mr Fred. High volume fuel rail needed E85.

Is that correct? <two tenths of an inch bore? OUCH! The straws at Wendy's are bigger than that, and I still can't suck a Frosty through one.

Remember, whatever you read about fuel rails using gasoline, add 30% to that for E85. 30% is a LOT. If your SO weighs 200 lbs, 30% more would be 260 lbs. BIG difference!

 

From Buschur himself:

I have run cars up to 600HP or more on stock rails, and lines. Only pump and injectors were changed. I have cars that are running 1600cc injectors and his double pumper fuel pumps that are still on stock rails, lines, and regulator.


If you have one already, sure install it. But you do not need to buy one till you are closing in on 600hp power levels.

 

id say talk to your tuner and see what he thinks is the best route to go to get more fuel. my tuner suggest a new rail,fpr since im leaning out on the top now. 1000cc inj, dbl pumper, fp red @30psi on E85. could i get more fuel just going to bigger injectors 1200 or 1600? maybe? but this is the way my tuner suggested to go and i trust his judgment

 

Remember, David was talking about gasoline. E85 requires 30% more fluid volume for the same amount of power.

Another way to look at it, is that E85 adds approx 20% HP over gasoline. That would make David's claim equate to approx 500HP on E85.

 

Bingo. Because everyone loves bad analogies: the fuel rail (and line leading back to the filter) is to your injectors as your intake manifold is to the valves. Think of it as a fuel "plenum", and you have a good idea of why you might want to make sure there's a bit of additional capacity there.

Regarding Buschur's experience, I'll only point out that those comments were most likely regarding conventional fuel, which (as everyone else has pointed out) can require as much as 30% less fuel volume. The other piece of missing information is whether the cars he's referring to are actually running the 1600s at reasonable duty cycles. A double-pumper and 1600s running at 50% IDC (fairly common on pump back when we didn't have anything between 1000s and 1600s) won't have a problem with a small-volume rail, and the flow rate of the dual pumps would help significantly with pressure recovery; that same configuration approaching 80% IDC may be a very different situation.

(This is actually an interesting question, because unlike fuel line, injector, and pump sizes, it's a bit more difficult to decide what would be ideal here than just running a few basic volume or flow rate calculations. Minimally, you'll want at enough internal volume to accommodate a single open injector, plus enough fuel to maintain supply to the other injectors. But, go too large on rail volume or too low on base pressure, and you won't be able to maintain enough internal pressure to atomize properly. I've always been curious about the decision that Mitsu made to radically change the rail between the DSMs and Evos; does anyone know if the IV-VII Evos had a "flat" rail like the VIII has? The next time I have the Evo rail off the car, I should measure the internal volume, and compare it to the two DSM rails I have sitting on the bench...)

 

I'd stay away from aluminum fuel rails. E85 is known to be corrosive to aluminum

 

E-85's corrosive properties are often blown out of proportion, usually because the poster doesn't understand what it is about ethanol that causes problems in the first place.

Ethanol is hydroscopic (just like brake fluid), which means it soaks up water like a sponge; the water, in turn, causes corrosion (and can be accelerated by the presence other contaminating metals, such as copper from brass fittings). Fill an aluminum can with water and let it sit; after a few months you'll start to see evidence of corrosion. A related, but more significant, problem is that while gasoline is non-conductive, ethanol (specifically, the water it absorbs) is, which means galvanic corrosion may eventually set in (see above about contaminating metals elsewhere in the system).

Regardless, in time you'll generate enough deposits to gum up a set of injectors without a cleaning regimen in place. In the case of fuel rails, internal annodizing should rectify the problem, but you certainly won't corrode enough of an aluminum fuel rail to cause a leak during it's service life without a significant contributing problem elsewhere. And, that's only one component of the entire system, so it isn't a replacement for occasional cleaning of the filter and injectors.

I'm also curious where you're finding these aftermarket non-aluminum fuel rails at.

 

^ That's what i call an informative post

 

Keep in mind that liquid is incompressible, so a larger volume will not enable any sort of damping effect like it does for air. Something that can expand and contract with the pressure pulses is needed to damp a liquid. In constant pressure situations, e.g., hydraulic pump systems, a pulsation damper is used for this purpose, however for a changing pressure environment like in an incoming fuel line, its impossible to use a conventional pulsation damper. The rubber fuel lines probably provide some damping capability, but I doubt its much because they are pretty stiff. There are damper solutions out there for fuel lines, but I've not researched them in detail.

On another note, the cross sectional flow area of the stock rail is actually pretty high. I posted some measurements somewhere on EvoM I think. Its just shaped funny. The only rail with a higher cross sectional flow area is the Perrin rail. My only thought with the stock rail is whether the squished cross sectional area significantly reduces the available flow to the injectors. Without some sort of good one-for-one test, its hard to say with any certainty.

 

What do you guys think of the Wilson fuel rail which is now available with the V2 intake manifold? I am no engineer and have no opinion other than that it looks cool.

 

I personally run e85 in my 1g DSM race car and your right the corrosive properties are usually blown way out of the water. I've run it for well over 2 years now and the fuel rail is fine and its the 18 year old stock unit! haha. I would suggest the E85 to anyone ough just b/c i've had one of my fuel pumps fail on me and it leaned out to a 13.5 air fuel and never knocked!

 

From my personal experience on my 2g GSX HTA35R, I'm making 600+whp on my stock rail on E85 with IDC's at 65% on FIC1600cc. My fuel system consists of -6AN feedlined from inline Bosch044 to stock rail to Aeromotive AFPR and back to stock return line.

IMO-Evo fuel setup are superior than older generations DSM's so why upgrade "unless" I find limitations during the tuning session. There are plenty of 1g/2g's pushing 60+lbs/min on ECMLink forum with their stock fuel system (lines, filter, and rail).

Just my 0.02.