Mythbuster: continuing project thread of my 1303 '75

[scourtaud]

Originally Posted by Wally

I have found the cause: my feed pump wasn't running well and I got stranded because it didn't run at that moment at all anymore!
Logical that when you have no fuel anymore, the engine dies out...duh!

I had a spare 944 pump I switched over and it started cold immediately again :mrgreen:
Pffft!
I left the fuel pressure to 60 psi, so according to the flow sheet that should give me 1180 cc, which should be enough anyways. Just need to re-map the fuel map but thats no biggie.

Very glad it was something this simple, but scary as it could have ended far worse. Amazingly and fortunately the engine held...

Hi,

I'm far from your level of power but running an EFI also and I recently had fuel delivery issues... It had nothing to do with the pump but by testing, I was amazed at how long the engine keeps running with the pump unplugged...
I've therefore decided to play it safe, always have a second pump in place, in case the first one lets go far from home...

Hope yours holds from now on...

And if I may add, you're car and its engine and quite amazing... and every time I recieve the "Post update", I just can't help thinking : What if I added even a small turbo to my 2007...

Sebastien

[Wally]

Originally Posted by scourtaud

... What if I added even a small turbo to my 2007...

Sebastien

Thanks Seb, but ^^thats what the tricky side of it is: people think adding a 'small turbo' gives only a little more hp, so its probably not so hard on the engine...
However, thats where you would go wrong! The smaller the turbo, the larger the exhaust restriction, the higher the Back Pressure in the exhaust, the higher your exhaust gas temperatures, the sooner you have knock and temperature related exhaust valve and valve seat problems.

IF your adding a turbo, use a large one with respect to your engine size and more specifically: also one with a relatively large turbine wheel compared to the compressor wheel.
Thats what I love about the Borg-Warners: their compressor-turbine wheel ratio is larger towards the turbine side compared to Garrett turbo's, which lowers back-pressure and increases efficiency.

[MX67]

I guess You have expectations from your engine. How much power You think it can handle and where's the limit?

[70Turbobug]

That's good to hear it was something simple and no damage caused!

[70Turbobug]

Just make sure your flux compensator is in tact lol

[Sandeep]

Originally Posted by 70Turbobug

Just make sure your flux compensator is in tact lol

LOL !

Its actually the Flux Capacitor, for the record Great series BTW.

Sandeep

[Steve C]

Hi Wally

What type of pump were you using as a feed pump? By feed pump is that the lift pump to the swirl pot?

Steve

[Wally]

Just a regular Bosch pump from a 3ltr or 3,2ltr 911.
Yes, its used as a lift pump to feed the 'swirl pot' or 'catch can' or whatever people call it, so I can still take corners after the tank is half empty.
The fact that its a pressure pump is not the reason it failed imo if thats what your thinking: it made gurgling noises when I used it as a pressure pump before already, but it always had done that. Since it never skipped a beat, I paid no attention to it, but that probably was a sign after all.

[70Turbobug]

Do you have the feed pump inline with the rest i.e tank-> feed pump -> catchcan -> Bosch pump , or does it have a seperate line from the tank into the catch can? The reason I´m asking is,I´ve seen a race car where the catch can had 2 inlets: one from the tank and one from the feed pump and it confused me why he did that..

[Xellex]

are you sure that inlet from the tank wasn't in fact a return -outlet- back to the tank from the catch can?

[70Turbobug]

Originally Posted by Xellex

are you sure that inlet from the tank wasn't in fact a return -outlet- back to the tank from the catch can?

That could be I didn't see where the lines went to

[Wally]

Originally Posted by Xellex

are you sure that inlet from the tank wasn't in fact a return -outlet- back to the tank from the catch can?

Why/how could that be the problem if the electric pump clearly was broke and it restarted fine with a new pump?
The lines run as intended btw

[Xellex]

Originally Posted by Wally

Why/how could that be the problem if the electric pump clearly was broke and it restarted fine with a new pump?
The lines run as intended btw

Hehe, there's been a misunderstanding, I was reffering to 70Turbobug's post about seeing a race car with 2 separate inlets from the tank to the catch can, and it has nothing to do with your electrical pump problem :P

[Wally]

No seperate and/or additional gravity feeding if thats what you mean.
Return line from regulator still goes back directly into the fuel tank close to wwhere the feed pump picks up the fuel from the tank.
Upper connection on catch can goes back to tank as overflow and also acts as a breather.
Pics of the set-up are on page 33: http://www.germanlook.net/forums/sho...t=9953&page=33

The idea of mine is/was that a zero-pressure feed pump (which is now the 944 pump) always supplies more fuel then the high pressure pump will be able to flow at 45 or 60 psi.

[Steve Arndt]

More header pics at the import site. They are WRX this time so a bit more relevent. Divided housing, but incorrect cylinder pairing

http://www.honda-tech.com/showthread...599745&page=18