3FE - Anyone Boosted their Fuel Pressures? (1 Viewer)

PF

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I just had Martin Davidson Automotive rebuild my 3FE with high(er) compression pistons. To get even more performance out of this engine I want to play around with boosting the fuel pressure. Does anyone have ideas or experience boosting the fuel pressure a few psi? If so, how?

Any aftermarket adjustable fuel pressure regulators available?
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I have been running these pistons (Ross Racing domed forged aluminum pistons) for 6 or 7 years now. I am assuming that is what they installed. Why do you want to increase the fuel pressure? These engines already run rich, and the compression bump is not really that large. Has the engine been installed yet? Does it ping? Did you go with a stock grind cam or an RV cam? Have you had your trottle body bored? And the exhaust manifolds cleaned up? There was also somebody out there that would tune the EFI system but I didn't think the cost was worth it on the 3FE. Remember that this is a tractor motor and you may not be happy with the results after all the money is spent. I just put in the pistons, I didn;t do all the rest but I would like to. With just bumping up the compression the ECU was able to compensate so I don;t have any pinging. I notice the power gain but it really isn't that significant, but it does rev a little faster now. I think the rebuild of my block which had 300K on it was the major factor but I do feel a slight difference in power. Also, the A440F is not the best tranny for the 3FE, when I put the H55 in it was night an day! Did the shop comment on passing smog in california? I think I have seen some adjustable FPRs for sale but again I am not so sure it needs it.
 
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Forgot to mention; if they haven't already done it have the mechanics tap and plug the oil galley hole on the head. If you don't know what I am talking about just do a search for it in the 60s section and you will see. Now is the time to do it, not when the plug fails and your rebuild is toast. They probably already did it but it is worth finding out.
 

PF

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Exactly! Nice to find someone who has some experience with this mod. Yes, those are the Ross Racing pistons and I had them do the cam as well. Like you said a noticable boost in performance, but still a tractor. My rebuild was due to a cracked head. I figure if I'm getting the pistons, I'll go for a few more mods. The H55 swap is in the plan next fall. Good to hear that makes a difference.

Two questions.
1. Do you run factory timing with your setup? I had to go from 7 to about 5 degrees just to get it to stop pinging. That's actually why I was going to start messing with fuel pressure.

2. Does yours idle low (about 500-550)? I keep unscrewing that screw on the throttle body, but it seems to keep settling on a low idle. It's that an idle screw?
 

Moby

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Out of curiosity, what is the static compression ratio with these pistons?

Boosting the fuel pressure probably isn't going to help if you are pinging in closed loop mode, the ECU will just trim back (decrease the pulse width of the injectors). A richer mixture will cool the intake charge but the ECU will just adapt. Of course as noted above these engines do run rich. I have a wideband o2 on my 2FE and I see 14.1-14.8 average (mostly 14.3-14.5) in cold loop and it goes into open loop and rich pretty aggressively.

Good luck trying to find someone to do custom tuning on this ECU to let the ECU provide a richer tune. Jet says they can do it but only has a "stock" tune. I tried to have a unichip install done but even with the shop working directly with unichip they couldn't get it to work. I'm currently installing a Split Second MAF to AFM kit to help tune open loop A/F ratios.

If you want to run more static timing without high load detonation get either a J&S Safeguard (aftermarket knock sensor and contoller - I run one on my 2FE) or a water/methanol injection kit (yes, these aren't just for forced induction). The J&S advantage is that it reacts specifically to knock. The water kits will keep the timing up but they can't tell if there is knock going on, so you have to tune and make sure the water comes on early enough and strong to eliminate the knock in all conditions.
 

Elbert

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don't think carbs tolerate much over the OEM fuel pressure rating?

my mistake...discussion on fuel injection..
 
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PF

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Based on these suggestions I think I'm over my "boosting the fuel pressure" idea (for now). Also wasn't planning to tap into the ECU. How do you put the ECU into open loop mode?-Jumpers? Without a knock sensor, what parameters does the ECU use to adjust timing? Whats a carbs? (j/k)

Moby - Haven't measured static compression on the new engine. The pistons are susposed to raise the compression ratio to 9.2:1. I would be curious as to your sucess with the aftermarker MAF system.

Anyone try aftermarket ignition? I know just enough to be dangerous.
 
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A domed piston is a less effective shape than a flat piston. Slightly dished is probably the best for efficiency. I would not pay extra for pistons when milling the head would be more effective and less expensive. I took .070" of a 2F and they had higher compression in stock trim than the 3FE does.
 

Moby

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Based on these suggestions I think I'm over my "boosting the fuel pressure" idea (for now). Also wasn't planning to tap into the ECU. How do you put the ECU into open loop mode?-Jumpers? Without a knock sensor, what parameters does the ECU use to adjust timing? Whats a carbs? (j/k)

Moby - Haven't measured static compression on the new engine. The pistons are susposed to raise the compression ratio to 9.2:1. I would be curious as to your sucess with the aftermarker MAF system.

Anyone try aftermarket ignition? I know just enough to be dangerous.
The ECU has timing tables that tell it to advance the timing x amount based on various engine parameters. There is no stock knock sensor so the timing system is in "open loop" so to speak (there is no feedback mechanism, like in the fuel system with o2 sensors). The J&S is a very simple install and effectively gives you closed loop timing control based on the presence of detonation. You'd be hard pressed to find a modern car with a knock sensor feedback today. Warranty claims alone probably more than justify the cost as detonation can quickly damage or destroy an engine.

An aftermarket ignition system will not help control detonation, at least not the systems for a 3FE. FWIW I've run both an MSD stacker ignition and the Davis HEI sold through man-a-fre (both with an MSD coil and Magnecor wires). Both add some power, but it is relatively modest. I'm currently running the Davis because the MSD is not compatible with the J&S. One or the of these is worth it if you are in the every bit helps camp (I have permanent residency in this camp).

in terms of open loop for fuel trim you could try disconnecting the o2 sensors. That will likely just put the ECU into limp mode though. Mileage and emissions will certainly be much worse in open loop even if you can achieve it. This is not a good solution. You'd be better off with water/meth system.

:cheers:
 
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i have a veary crude water injection on my 3fe,if you want to see if it will provide any benifts for you, take a gallon jug drill small hole in lid, run a piece of fish tank air tube through the jug lid, put a fish tank rock filter on the end of hose in jug. them put hypodermic neddle size 20g in the other end of hose, then insert it into vaccume line running on top of manifold, eather one right above throttle body. the vaccum will draw water throgh when you rev engine but not while you are idleing. make sure the water jug is not above the needle or you will have engine full of water. cost abot 10.00 for parts to build this crude system.
one great benifit it cleans the carbon out of youe engine.
 
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PF- Remember that my 3FE with manual tranny doesn't ping so if yours does then something is wrong. How many miles are on your engine since the rebuild? Does it ping with premium in the tank? Is your cooling system up to par? My engine did ping in the beginning but it turned out to be an old radiator. Changed the radiator then all was good. My 3FE idles at 650 RPMs and when cold idles high and gradually comes down to 650 RPM. Did you say that you had an RV cam installed or was it just a new stock grind cam?
 
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amost forgot , i have adjustable fpr on my 3fe and have expermented with diff psi, and have not noticed any gains or losses in power, also have air fuel meter, and it reads same at diff fuel psi levels, as well. easy way to boost fuel pressure, is to take off vaccume line running to fpr, it will then have 60psi fuel pressure ,wich is to much , but will give you a idea if it will give more power.
 

PF

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PF- Remember that my 3FE with manual tranny doesn't ping so if yours does then something is wrong. How many miles are on your engine since the rebuild? Does it ping with premium in the tank? Is your cooling system up to par? My engine did ping in the beginning but it turned out to be an old radiator. Changed the radiator then all was good. My 3FE idles at 650 RPMs and when cold idles high and gradually comes down to 650 RPM. Did you say that you had an RV cam installed or was it just a new stock grind cam?
Aseif007 - Engine has just crested 500 miles. I'm going to change the oil, adj. the valves and reset the timing now. It pings with the stock timing. Installed is an RV cam, not stock, so my valve clearance is a variant on stock. The cooling system works well. I had the core replaced a couple years ago and, of course, installed a new water pump. Based on dash readouts the temps are nominal to cool. Idle is still too low once it's warm. I use 91 octane. Maybe it's just new.

I swap diffs with Mr. Mace this weekend, then do 500 mile maintanence. Then, we will see if where it is pinging.

Moby - Thanks for being a pioneer in the camp of "every little bit helps". I'm a follower in that camp.
 

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