Factory Fuel Filter loop/bypass

a951 wrote:thats just silly, the placement, stock tank etc for stock is very good.

I hope to assume you are beeing funny as he puts a lot into the mechanical/machine/engineer perspective of things, in that case, haha

I have no idea what you mean. I cant even begin to see my post as silly or insulting. Well, it is in big letters so thats kinda silly. But still.

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Off topic

Theres a few common reasons that all modern vehicles use intank fuel pumps. Heres a few:
1. They run cooler - being inside the tank keeps the pump cool which means cool fuel which also means longevity of the pump and better performance. Ever felt an inline after awhile of driving?
2. More efficient - being inside the tank, the entire length of fuel line to the engine is pressurized with fuel. Theres no chance of vapor lock or starving of the engine due to pump cavitation.
3. No cavitation issues - a leading cause of fuel delivery issues in racing/motorsports
4. Quieter (far quiter) - no annoying droaning. No transmittance of vibration/harmonics to the frame.
5. Performance:Cost - theyre cheap and are generally more capable of producing higher psi than most equal dollar inline pumps

The only drawback is that its a pita to replace and, for us, would have to have the tank a bit modified. Would it be worth it all? Id like to think so.

The tank is plastic as I took a wrench to it and thumped it. I wonder if it's polyethylene or polypropylene. I changed the filter and it was severely restricted. I shook out the influent side and it looked like small turbid soot. Got me thinking what material the filter has. Anyways was happy not to see large chunks, and glad to know the filter left in place will save my C5 filter/regulator. Anyways fired it up and she is banging a new tune, the fuel rail is reading 43 psi (should be mid 50's), so I am thinking the fuel pump may have been fragged due to the filter getting clogged severely. I'll change that this weekend. Big question, does it matter which way the leads are hooked up on the new TRE-200 filter?
And speaking of mods, do the newer pumps have brushless motors in them. I've worked on alot of different types of pumps and the ones that are brushless last forever and don't get as hot, you just have to change bearings and impeller.

Marky522 wrote:Yeah, my vote is pump also. And if you need one I would go with the GSL walboro inline pump, same specs as the 044 pump for $100! Oh and all your origional fittings thread right into it. MY suggestion is to gut the check valve on the output side as the walboro already has one built in.

Mark

I would highly recommend going after an actual 044 if you have the money. I've seen quite a few failures out of the Walbro pumps in the BMW market, and that's intank.

As for an intank conversion, it would probably be pretty easy. All you would have to do is find a pump setup that would fit where the fuel level sender is and just have the pump with a level sender on it. The only problem would be how deep you can get into the tank, since it is fairly tall compared to most tanks. If you do that, changing the pump would be easier than it is now: just pop the hatch, lift the carpet, lift the fuel level sender, and get it all from there. No need to worry about emptying the tank or pinching the pre-pump line or the likes.

I bought a real 044, then you know you wont starve any time soon.

Really? I have never heard of walbro issues. That's pretty much all anyone uses in the Mustang world. I'm sure they die after a few million miles, but whatever.

Those BMW guys are probably running them backwards or something.

Porch wrote:Really? I have never heard of walbro issues. That's pretty much all anyone uses in the Mustang world. I'm sure they die after a few million miles, but whatever.

Those BMW guys are probably running them backwards or something.

I'm running the TRE-200 and have been for 1 year now. No problems and the fuel starvation problem I had with the stock pump is gone. IIRC I posted the link to their page on this site when it started, maybe evern the RH board too.

X I plugged it in as diagramed + to + - to -.

Thanks Tim, I guess I need to open the box up and look LOL. Will get on it this WE.

Also Forgot to mention that the old filter's end fittings can be removed and an adapter made to connect the two (loop). I don't think there is enough hose length to just simply mate the factory lines after removing the fuel filter anyways.

You need to be VERY careful with the Walboro, my understanding is there are alot of cheap imitations. I have a true Walboro and well see... The price was right...

Mark

robstah wrote:

Oh, lighten up.
Seriously, like half the performance world runs Walbro's. I'm sure they're not unbreakable but they have a great reputation.

Just to clarify the situation.........Is the TRE-200 a straight swap for the NA 1988 pump?
If not, what else is required?

I assume that the stock pump is not up to the job.

Thanks guys.

off topic slightly,

While you are talking N/A pumps, I am wondering what do Turbo models have? Are they any better?

My mentality is if your running a stock pump, more than likely the higher pressure will kill the pump pretty quickly. I am sure some people get away with it but for the insurance i didnt want it to be an issue.

Mark

What was the stock 944 pressure compared to the ls1?

cfgioja wrote:
While you are talking N/A pumps, I am wondering what do Turbo models have? Are they any better?

The Turbo cars run a Bosch 044 which is well-known as a great external pump. I don't know what the N/A's have, but i doubt it's the same.

stock turbo pump, is the unit slightly smaller than 044, but in same series, and very good unit, but doesnt support the power that 044 does.

cfgioja wrote:What was the stock 944 pressure compared to the ls1?

Mid 40s to 50psi. I doubt an extra 10psi is going to hurt. A lot of the upgraded turbo guys push higher pressures when going to bigger injectors and the likes.

From Lindsey Racing's website:

The Bosch "HV" Fuel pump has been used by us on 951s producing 460 RWHP. To date we have sold several hundred of these pumps and it does a great job for most everybody unless you're thinking over 450 RWHP sustained. We have had customers stating that it has supported as much as 504 RWHP on their vehicles.

The Bosch "044" Pump has a reputation of being able to support greater HP. We cannot confirm it's capabilities at this time. We do feel at this level of HP, there are other things to consider besides the fuel pump. Line size, pick up size, fuel regulator size and most important, the fuel pressure check valve size. Check our install tech page for more info on that.

So the turbo models do not have a 044. If anything, it's definitely weaker in comparison and probably matches that close to the HV pump that Lindsey sells. I also see Pelican Parts selling a 3.8bar (55psi) fuel regulator for the late model S2s and 968s, but they also had a different pump. Also understand that these pumps are from the 80s and have been around for a while now.

xschop wrote:Thanks Tim, I guess I need to open the box up and look LOL. Will get on it this WE.

Also Forgot to mention that the old filter's end fittings can be removed and an adapter made to connect the two (loop). I don't think there is enough hose length to just simply mate the factory lines after removing the fuel filter anyways.

Check out the bottom of the page:

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It may be wise to delete the stock fuel filter.

Hmmm.... I'll check the "check valve" when I dismantle the old pump. It's there for a reason. You have heard the term "$hit rolls down hill" haven't you? LOL. The debris caught by the influent side of the filter would always gravitate back into the pump,would be the only downside. Also could your injectors dry out quickly? Don't know if that would be a concern or not.....I'll post what I find there.

xschop wrote:Hmmm.... I'll check the "check valve" when I dismantle the old pump. It's there for a reason. You have heard the term "$hit rolls down hill" haven't you? LOL. The debris caught by the influent side of the filter would always gravitate back into the pump,would be the only downside. Also could your injectors dry out quickly? Don't know if that would be a concern or not.....I'll post what I find there.

The injectors drying out is the main reason it's there.

I stand corrected, i thought the 951's had the 044.

All 944's use the same Fuel pump. There is no difference between N/A and turbo. The 044 pump would be great, but the TRE-200 is better than stock, $90, and direct bolt on.

Thanks to Dawg again for finding this pump. Even when the old pump was still good, I had a random High RPM backfire (I suspect a lean condition due to the choking 944 FP)that is completely gone... and more power to the ground at high RPM. PSI is back to 55 at the rail. The TRE-200 even squeezes back into the foam rubber housing (with a little sweet-talking). FYI....No need to drill the check valve either as it is a little larger than the factory pump as well....

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Glad you got it fixed!

Just in time to give my Wilwood/Cayenne swap a thorough testing after work:twisted:
Amazing stopping power with a 3/4" master.....zero fade