You guys think that running idemitsu premix will cause a bunch of that black crude on the fuel sock? I have been using the premix for sometime now.

 

Team can you explain the cause and effect of excessive fuel recirculation, as i'm sure i will be dealing with this at some point, if not already. I currently have the Aeromotive 11142 stealth fuel pump in my stock daily driven 8.

 

More capacity than needed results in more fuel being pumped through the regulator bypass.....and a small amount of heat being added to the fuel.

On a returnless system this isn't really a huge problem because the oversupply happens in the fuel tank..and the added heat is just from the pump

In a return system where the fuel returns from the engine compartment where there is more heat added to the system...so more of a problem

I would be more worried about what is happenning with fuel slosh...and pump starvation than I would with the other problem...and the increased outflow should result in better suction on the venturi fuel transfer system...and better results

 

No...it's not the premix...( with Idemitsu anyway )...it's the crappy fuel you are getting

 

You will be fine as long as you aren't going around corners If you are...all bets are off unless you do something about it

 

i conclude Aermotive would be just fine and pumping to the max is ok... but not advisable...

and agree with Dan on Idemitsu... Been using them... white smoke when startin, other than that, fuel sock is white as snow (with some dirt)

 

Until you get a low tank level and do a lot of cruising/idling, then you are running the same small amount of fuel through the pump over and over and over again adding heat to it on each pass through. It's not just the pump losses but also friction through the bypass. With a 320 lph pump you essentially double the fuel pump size beyong the original, but at idle and cruise are not using much or any more in closed loop low engine speed operation. Most people are thinking it can't be adding that much heat, but having designed recirculating piping systems with pumps I can assure you that in a low tank scenario it can and will get hot under the right circumstances. You could make the same argument that an external bypass line might gain heat in the engine bay, but has more opportunity to lose that heat because the long return line is also a long heat exchanger whereas the internal bypass dumps the heat gain back directly into itself.

 

My problems occured on 2/3 full tank. I think the 107F ambient temp contributed to the problem. Amazingly the oil temp gague sat steady at around 176F.

I would be interested in seeing how others go on a long 8 to 10 hr road trip with the aeromotive pump in similar ambient conditions.

 

Crazy heat you guys are having down there. I was reading the other day it was 115F in Melbourne. Get in touch with the Arizona Rotary Club and see if they have any suggestions. They have similar heat in their summer.

 

Some remote towns have higher temps week in week out. It has become so hot that bitumen on the roads has started to melt.

 

Replaced the pump with one from BHR yesterday. Thanks to this DIY and the one from StealthTL. Had all the symptoms listed and it has been driving me nuts for awhile now. Can't complain too much though, the stock pump had 296K on it. Borrowed the tool from my local Autozone.

 

I just had a thought, if you have pulled your fuel pump assy apart before you would know there are two parts, the main housing and the internal parts which hold the fuel pump, I was wondering if the internal s2 part would fit into the external s1 housing part?

The main reason I believe for the swap is the s2 fuel fuel pressure regulator works a bit differently and is a benefit on the track, regarding fuel starvation.

 

no it will not fit directly. The s2 cup is a better design anyway.

 

+1 Like

 

Damm, the bucket looked similar in pics.

 

What is the best way to hook up the siphon if the fuel system has to have a return line? The previous owner tried to hook it up but it still isn't working. Any help is very much appreciated. If I get it working, fuel cell in trunk here I come Lol.

 

return from regulator has to attach to the siphon unit. It requires another fitting on the top of the pump cover to allow it to go into the tank

 

hook it up to this?

 

Yes....that's it

 

this is the s2 fuel pump assembly yes?

 

No this is the series 1

 

okz, got it... thanks dznutzuk

 

Had to replace my aeromotive fuel pump this weekend. Took a trip to Arkansas to run some roads and the pump keep randomly cutting out. I guess cavitation or excessive recirculation, i really don't know. I just yanked the whole fuel element and replaced with used fuel element with oem fuel pump and no more problems, even after 8 hours of twistie roads.

My experience thus far...increased output fuel pumps are not a good idea for stock Rx8's. Unless i have some other issue causing my pumps to fail. If this stock fuel pump fails prematurely i will have to think about what else could be causing my fuel pumps to fail.

 

I had the same issues on my FI car during a long trip. Also resolved by dropping a oem pump.

 

I agree .....

OD had it right all along with the S2 pump. All hail OD