I have seen various threads on fuel pump problems and how our fuel system, plainly sucks.

I have wondered why do we use an "in tank" pump at all.
Drill a hole in the lowest portion of the bottom of the tank, install AN 10 or 12 fittings and re-plumb from there using a good external pump.

What am I missing here?
(I am usually missing something, when I am seeing an "obvious" solution like this):uhh:

Does the fuel injection system change fuel pump pressure to control the air fuel mixture?


Norm.

There is nothing really wrong with the in-tank pump design. Its just that the stock pump can't hold high pressure settings for too long. (heat)

I have seen various threads on fuel pump problems and how our fuel system, plainly sucks.

I have wondered why do we use an "in tank" pump at all.
Drill a hole in the lowest portion of the bottom of the tank, install AN 10 or 12 fittings and re-plumb from there using a good external pump.

What am I missing here?
(I am usually missing something, when I am seeing an "obvious" solution like this):uhh:

Does the fuel injection system change fuel pump pressure to control the air fuel mixture?


Norm.

Biggest problem is the saddle tank design of the stock tank...you would need to drill both sides......the tank also is flat bottomed and the fuel pickup hole would spend a lot of it's time uncovered...not a good thing for fuel pressure.

Most of the problems are from the tank slosh in high speed corners, and from marginal stock pump outputs for upgraded applications

1) I disagree.
2) Assembly simplicity.
3) The OEM pressure operating is 58-60 psi and the PCM controls the injectors based on load.

Ah, so the air fuel ratio is controlled by fuel pump pressure.
So much for recreating the wheel on this one.

Thanks for the information.

Norm

Ah, so the air fuel ratio is controlled by fuel pump pressure.
So much for recreating the wheel on this one.

Thanks for the information.

Norm

Not really...the fuel pump speed changes with higher loads to keep the flow up and thus the pressure stable. The regulated pressure stays the same.

Rote8: I think your sig is stupid.

Maybe I need to put in my sig how slow SC's are.

Check out my engine rebuild thread. My housings, seals, rotors, etc were all fantastic. If I didn't already buy all new housings and seals, I could have reused everything.

I ran quite a bit over 300 whp too with the 3071R.

Anyway, my point is that the sig insinuates that turbos are not safe for the renesis. As if SC boost is softer and more gentle. :pat:

^if you noticed, I've seen a bunch of other pettit SC owners have that "theory" in their sig.

Aww, I feel the love...the turbo guys bashing on the SC guys, the SC guys bashing on the turbo guys. Who really gives a f***! LOL!

Sorry for the hijack!

BTW, we tried external fuel pumps on the race cars before...didn't really help out as much as we thought it would. Went back to the in-tank.

i'm not bashing anyone, I have nothing against the SC or anyone who runs one...i just agree with mysql that it is kind of pointless to have this theory in your sig

The point of the sig should be apparent. It's misleading.

It is not misleading for anyone that is thinking. Quit being so dang sensitive dude and be a little open minded. This theory is coming from Cam at Pettit Racing who sells the pettit s.c. kit duh--he also builds turbo renasis engines for the diaso track cars---putting out over 400hp--i believe to the best of my knowledge that he has gotten more power out of our engine than anyone. he has nothing against turbos obviously--he is only sharing info he has found--he doesnt have to do it. But he does.
But dont look at it, dont read it, dont learn--just cry out that it is "misleading" and miss your chance to learn a little bit from someone that knows one hell of a lot more than we do.
Ego's get in the way of learning and having fun. So be it.
olddragger

It is not misleading for anyone that is thinking. Quit being so dang sensitive dude and be a little open minded. This theory is coming from Cam at Pettit Racing who sells the pettit s.c. kit duh--he also builds turbo renasis engines for the diaso track cars---putting out over 400hp--i believe to the best of my knowledge that he has gotten more power out of our engine than anyone. he has nothing against turbos obviously--he is only sharing info he has found--he doesnt have to do it. But he does.
But dont look at it, dont read it, dont learn--just cry out that it is "misleading" and miss your chance to learn a little bit from someone that knows one hell of a lot more than we do.
Ego's get in the way of learning and having fun. So be it.
olddragger

I am not questioning the source. I am questioning it's use.

You'd have to be pretty naive to think that the SC guys have it in their sigs as a way to inform us of issues with boost.

I may put a link to the dyno thread in my sig with a caption of "Theory why SC's are slower, by dyno machines worldwide"

Anyway, I had thought we were over this sort of thing, but apparently not.

if you thought we were over it then why did you bring it up? That attachment has been around a long time--for months. Why say something now?
OD

here we go

na I am done man--it aint worth it. Sorry in getting the thread off track. the thig he mentions it shows what is happening to the exhaust ports and seals when over 10-11 lbs of boost is being placed on the engine without exhaust port work. currently no supercharger for our car can put out that kind of boost. Thats why the "turbo" word is there and not supercharger.
olddragger

if you thought we were over it then why did you bring it up? That attachment has been around a long time--for months. Why say something now?
OD

I just noticed it in his sig. Believe it or not, I don't look around the forum at SC guy's sigs all day :P

BTW, 12 PSI is where my car spent about 10,000 miles. Did you see the engine rebuild pics?

Maybe it's because I have better cooling than the stock system, sohn mod, synthetic oil, and so on.

maybe so, cam does some exhaust port work so the cooling is better in that area.
at 12 lbs and with a good tune I bet she was real snappy:)
did you add a second radiator? You may want to consider that later on. If so--i will be glad to share with ya what we have done.
OD

12 psi on the 3071R is amazing. It makes the greddy turbo feel like a stock RX-8 because it has so much more torque.

Right now my radiator seems to be working well. It sits around 183 most of the time, but I've seen it go up to 190 F.

I've got the re-medy water pump, Almost 100% distilled water (water wetter in the mix), underdriven pulleys, and the AP with radiator fans increased.

Still harping about Pettit’s SC. Here is another SC owner’s signature and do pay attention to the last statement. :eyetwitch

so.. fuel pumps.

i wish I can run 100% distilled water in NYC. :(

I'll try to run it like 20/80 next summer, just to see how it goes.

ahh, back to fuel pump.

As it so happens, I just changed my radiator fluid today. This time around I put in a little coolant. Maybe 5% just for shits and giggles. Will be interesting to see if temps change any - I am going to assume not given the nature of the cooling system and that it maintains a specific temp range.

Still harping about Pettit’s SC. Here is another SC owner’s signature and do pay attention to the last statement. :eyetwitch

Thanks for making my point about the logic of the sigs by SC owners :)

I guess this means I can safely ignore you.

Thanks for making my point about the logic of the sigs by SC owners :)

I guess this means I can safely ignore you.

I thought you went NA?

HEY jUAN--YOUR DYNOPULL IN 5TH GEAR WAS ONLY 5SEC'S---DAMNNNN!
mysgl--i thought you needed a little coolant in the rad for water pump lube?
You live in the south dont ya? So you see hot days--those are pretty good temps.
do you track?
i have been running a 70/30 for a long time --i use the DEI brand coolant additive--Juan and I saw how the redline brand foamed up (he saw it 1st and discovered the dei brand didnt)by using it in our a/w intercooler system. Our tank would be completly filled with foam with the dei it doesnt.
Did you tune yourself?
OD

oh sorry --back to fuel pumps
i just change mine about every yr now--so no probs.
OD

oh sorry --back to fuel pumps
i just change mine about every yr now--so no probs.
OD

Wow, I'm autocrossing and I haven't had a problem yet. I've been premixing as well. Although I haven't even owned the car for a full year.

2 of my friends that autocross had problems as well. Both premixed. I'm wondering if it is brand of gas used or something. Maybe certain additives are impacting things.

Also I dump 4oz of idemitsu in the gas tank before fill up. I don't premix it with gas first.

HEY JUAN--YOUR DYNOPULL IN 5TH GEAR WAS ONLY 5SEC'S---DAMNNNN! OD

Only to third gear OD.

Anyway, how about using two OEM pumps (parallel)? I removed the rear passenger seat and upper passenger side gas tank cover once and it looked just the same as the driver side. :eyetwitch

Only to third gear OD.

Anyway, how about using two OEM pumps (parallel)? I removed the rear passenger seat and upper passenger side gas tank cover once and it looked just the same as the driver side. :eyetwitch

It is the same...but there are problems...

If you want to do it PM me and I can give you some pointers :)

yep Dan did that one--he did a lot of work on that.
OD

old pisicshttp://www.rx8club.com/attachment.php?attachmentid=127926&stc=1&d=1224556558
104_0015_320x240.jpghttp://www.rx8club.com/attachment.php?attachmentid=127927&stc=1&d=1224556580
104_0019_320x240.jpghttp://www.rx8club.com/attachment.php?attachmentid=127928&stc=1&d=1224556597
104_0025_320x240.jpg

these are some oldpics
OD

that black stuff on the internal filter was oily residue.
OD

http://www.rx8club.com/attachment.php?attachmentid=127929&stc=1&d=1224556839
104_0022_320x240.jpg
you can see it here.
OD

I read the whole don't premix thread and the fuel pump threads. I also remember mazdamaniac saying its possible to take the fuel pump apart without cutting it.

I've never seen one in person, but is it possible to take it apart to get to the internal filter and be able to put it back together and make it operational?

It would be nice to remove the internal fuel filter and put an external fuel filter on the fuel line itself. Doesn't solve the problem with the sock though.

I guess if it was that easy someone would of tried it by now.

I have an external filter on mine.....1 micron.

One Mazsport pump and 1 OEM pump.....

MM says he can do it--I cant.
Dan how did you get the internal filter out? Or did you?
With the 2 pumps were you able to keep the safety functions?
Interested.
thanks
olddragger