Go Back   Rotary Car Club > Tech Discussion > RX-7 3rd Gen Specific (1993-2002)

RX-7 3rd Gen Specific (1993-2002) RX-7 1993-2002 Discussion including performance modifications and Technical Support Sections.

Reply
 
Thread Tools Display Modes
Old 10-15-2017, 11:14 AM   #1
speedjunkie
RCC Loves Me Not You
 
speedjunkie's Avatar
 
Join Date: Mar 2008
Location: Colorado Springs, CO
iTrader: (1)
Posts: 2,054
Rep Power: 12
speedjunkie is on a distinguished road
Default Alright rotary geniuses, I have fuel surge questions

I've been looking for an anti-slosh solution for a while, but nothing so far has met all my wants and needs and I think I've finally figured out what I want to do. I'm currently using dual Walbro 450s and they each feed one of the fuel rails as of right now. I'd like to switch it back to both pumps feeding both fuel rails, but I need to sort out the pulsation issue I had before with that setup, whether it be a larger fuel rail or what. I'm not using flex fuel yet but the car is set up for it. I may not ever use it, I'm not sure yet.

I'm planning on building a little tank from stainless steel that sits in the stock plastic box, and I'll run a hose from each fuel pump to that tank. From both sides of the tank will run a line (probably stainless hard line) to a Holley Hydramat at the far ends of the tank on both sides, using a one way check valve on each line just before the tank. I will run a stainless hard line from the return line back to the tank as well, dipping down to the bottom of the tank so the return fuel can be cooled a little by the rest of the fuel in the tank. I will also put a lid on the top because I'll have to fill it with fuel first since it will be a sealed system, and because of all this I will probably also put a one way check valve going out the top so excess fuel or pressure can be leaked out into the main tank. I've also thought about scraping the protective coating off the bottom of the tank and attaching heat sinks to cool the fuel.

Because it will be a sealed system, it will be pulling the fuel back through the return line instead of just flowing normally. Theoretically, whatever amount of fuel I put into the surge tank to prime it, should be the amount it always has regardless of the load on the engine. Although it might not be a good idea running the return line straight to it, because the return will flow different rates depending on engine load. I imagine it will suck fuel out under heavy throttle, but light throttle or idle I wonder if it will back up in the line. However, whatever the flow in the return line is should mimic whatever the pumps are doing, so maybe that's a non-issue anyway.

Thoughts? What factors am I not considering?







Last edited by speedjunkie; 10-15-2017 at 11:41 AM..
speedjunkie is offline   Reply With Quote
Old 10-15-2017, 08:03 PM   #2
JL1RX7
Rotary Fanatic
 
Join Date: Feb 2008
Location: Front Royal, VA
iTrader: (1)
Posts: 485
Rep Power: 10
JL1RX7 will become famous soon enough
Default

Buy different pumps. Walbro should be called wallet blown. Aeromotive or the like will be better served. Expensive yes. But do couple hundred bucks vs redoing a blown motor.

The angry one knows surge tanks and that type of set up. Hopefully he will chime in.
JL1RX7 is offline   Reply With Quote
Old 10-16-2017, 01:55 PM   #3
speedjunkie
RCC Loves Me Not You
 
speedjunkie's Avatar
 
Join Date: Mar 2008
Location: Colorado Springs, CO
iTrader: (1)
Posts: 2,054
Rep Power: 12
speedjunkie is on a distinguished road
Default

Well I've never heard much good about the old Walbros so I was nervous about using these. But I haven't heard anything bad about these and they've been good for me so far. I also got two so if one failed I'd still be OK. On top of all that, I have failsafes set up in the ECU using sensors just after the filters so that if I get low or no fuel pressure it shuts the car down. So I have redundancy after redundancy, but I want more safety HAHA. The reason I went with these is because I knew they'd be good with E85. I wasn't sure about AEM, Aeromotive, or the others. I had Bosch 044s that I was going to use but I sold those when I decided to do flex fuel. And now I'm concerned about using E85 anyway haha, I just feel like there hasn't been enough evidence yet that it's OK on the engine. Not to mention the flex fuel sensor doesn't detect water, ugh. I'm just on the fence still. I overbuild each system so that it protects the engine, but I wouldn't have it any other way.

I'd like to get some fuel pumps that are more known to be reliable that are also good with E85 (just in case I decide to use it eventually) and have a more solid way of connecting hoses to the inlet for this project. I've done some searching but I haven't seen much yet.

Yeah Brian PM'd me haha.
speedjunkie is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:28 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Hosted by www.GotPlacement.com
Ad Management by RedTyger