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Race/street car electrical loads & alternator choice

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Canadian_CD9A

Supporting Member
1,077
833
Feb 10, 2012
Winnipeg, MB_Canada
I've had a lot of downtime since COVID-19 hit and noticed that my plan calls for a huge electrical load on the system. I've found approximations of amperage draws for the following:

-MR2 electric power steering pump: 30-40 amps typical load, up to 70-90 amps max load.
-Tilton transmission cooler pump: 2-3 amps typical load, 6.6 amps max load.
-In-tank Walbro 255 puller pump: approximately 5.2 amps @ 10 psi fuel pressure.
-Bosch 044s (or similar) pusher pumps x2: 9.73 amps each @ 40 psi fuel pressure, 13 amps each @ 130 psi.
-12" Spal fan (or similar), approximately 1200 cfm: 14.5 amps.
-Ignition amplifier box: 6-20 amps, plus 6 amps per coil.

All in all, this adds up to a lot of electrical load on the system, not even counting the general accessories (lights, ECU, sensors, injectors, etc). How do DSMers and Evo owners typically deal with this? Is it as simple as a big alternator and upgraded wires? What alternator would work best, and what other tricks does Tuners have?
 
Most of the cars that get built dosn the road always tent to go down in alt amp size. Even eith a mass amount of electronics. I was told my 90amp galant unit was still overkill.

The battery will still take up some of this load and the alt will just replace the energy when it can.
Im no electrical expert so my comment is not backed up with hard data and its mostly what i been told by the guys who do this dsily for race cars so i do listen to them alot.
 
I would agree, but my good friend has the MR2 power steering pump on his EM1 Civic (90 amp alternator?) and says that his charging system can't keep up at idle with the headlights on. Even though I don't have a stereo or power anything in mine, add 3 big fuel pumps, a transmission cooler pump and an ignition amp - it just wouldn't work. I'm thinking the alternator output has to be somewhere in the neighborhood of 150 amps.
 
Have a look at the small compact race alternators. But also do you have all AC and other things removed as that will help ease the load some more. Heated windows / elements draws alot.

I wonder why the mr2 pumps use so many amps? Is is because its half electo and half hydro?
 
Still interesting why people don't use the gm electric power steering from a Saturn Vue or Chevy equinox for these cars. I've been doing one in my spare time to test.
But you have to consider the batteries amperage capabilities and the steady supply of the alternator, as well as the only momentary usage for some of the components. Everything is variable.
 
If you have an under-drive pulley you would need something a little stronger.

Maybe your friend in the Civic has an under-drive pulley?

It was a stock K20A on factory pulleys. The MR2 pump saps that much power.

I have considered the electric steering rack, but the MR2 pump still maintains some steering feedback; I don't know nearly enough about the electric racks to consider it yet. Maybe there are some better pumps out there now, but the MR2 has always been the go-to.
 
I installed a brand new MR2 ehps pump back when I was building my car, I would'nt think of running that pump at full blast all of the time, the factory never intended it to run that way and it will over boost the steering and use too much power and the pump will get too hot and kill the brushes in short order anyway, I installed a couple of large resistors to slow it to a low crawl to add just enough power for me to be able to drive it without being more difficult than a manual rack, it draws very little amperage setup that way, I measured it at one point and if I remember right it was like under 10 amps.
 
One comment I'll leave with, is that no fing way you need all the fuel pump. A single AEM 400 would likely be overkill. For reference, my car has just 2 walbro 255 externals. I'm pushing that through a restrictive stock fuel line, fuel filter, and 2 factory hoses on a double banjo bolt. Idk what it really makes for power right now, but it made over 750 on an engine dyno, and it makes more now. It's 30-35psi, close to 80lbs/in when it's cool out, and on E85. No signs of being out of fuel pump at all.
I'd assume being in Canada you will be on gas only, and probably a 500hp or so target. 1 bosch 044 is more than enough. Even a single 255 will get it done. I assume you are doing a surge tank deal. I'd skip it, but if you have to have it, find a different pump for the pusher.
 
Not sure what the planned fuel setup is.
But I consider the 044 to be obsolete now with the new pumps we have available to us today.

in my trails I found data on the 044 saying ~260lph @ ~70psi pump pressure. That’s not great and I would’ve expected more in my opinion. I think it may be conservative, but nonetheless that’s concrete data to go off of.
I’m REAL familiar with Walbro and Aeromotive.
The Walbro 525 is 290lph @ 80psi pump pressure! @12 volts!!! Lol. That’s 36 psi of boost @ 43.5 base fuel pressure.
The Aeromotive A1000 is 300lph @ 80psi.


The galant 90A alternator is great upgrade over the stock 75A alternator.
Not sure the cars intended purpose here? If it’s strictly a track car the Galant 90A should be more than sufficient. Any demand greater than what the alternator can produce is gonna come from battery.
Research / Upgrade Big 3 and upgrade supply from alternator to battery if not done already.

If this were a daily I think you’d be okay but at really high demand periods I could potentially see voltage drops. I wish there were options for 110-125 amps for our vehicles because I was looking for something in that range just for daily driving upgraded car audio equipment. I’ve seen other people running a Saturn alt? At 200A output. Which is NUTZ!
What motomatt described. Something similar to that sounds like it’d be a really good way to go.
 
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Saturn Alternators came as 90-105A from the factory IIRC. They are modified to put out 200a. Different stators, upgraded regulators, and I really dont know what else.

You can get them in 90A,105A, 120A,160A, 200A, 220A and 250A (that I know of)
 
I have mr2 ehps installed on my 1g. It is from 2001 and up mr2 because the module is build in into the pump. I have an old battery with stock alternator. At idle when turning the steering wheel, I tested with an amp clamp, my alternator is pulling its hair out. It pulls 60 amps and my voltage dips into 11 volts. Now having discharged battery don't help but it is not my daily. Also some interesting facts, their is a wire that you can hook up to the vehicle speed sensor to slow the pump down when moving and their is a wire that tells the ecm to raise the rpm at idle. Both of those wires are not hooked up on my car. I will hook them up one day but not now. Also steering response at stand still is a bit harder then stock, when moving you can't even tell. Also if the car is build to autocross then don't do mr2 pump. It creates lag in my opinion. For daily or for drag car it is ok but not for autocross or road racing.
 
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The prius electric steering motor is fused at 60A on my setup. Has never blown. To increase or decrease the amount of steering assistance, I turn a potentiometer knob left or right.

I looked at ehps in the past, but with the Quaife manual steering rack coming, I went with something that didn't require a working spool valve in the rack and pinion. Added benefit of no more PS hoses, lines, pump, rack seals, or fluid to leak out.
 
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The prius electric steering motor is fused at 60A on my setup. Has never blown. To increase or decrease the amount of steering assistance, I turn a potentiometer knob left or right.

I looked at ehps in the past, but with the Quaife manual steering rack coming, I went with something that didn't require a working spool valve in the rack and pinion. Added benefit of no more PS hoses, lines, pump, rack seals, or fluid to leak out.

I think I looked at your build or posts when I was doing my research. You have a nice set up. Unfortunately my fabricating skills are not up to the level of yours to be able to pull something like that off. But you are correct, ehps require fluids and hoses and I don't like it but at this point it is better then having manual rack. I believe my fuse is 50 amps and so far it never popped.
 
Saturn Alternators came as 90-105A from the factory IIRC. They are modified to put out 200a. Different stators, upgraded regulators, and I really dont know what else.

You can get them in 90A,105A, 120A,160A, 200A, 220A and 250A (that I know of)
I am doing my research while I am laid of due to corona virus and Saturn alternator is an option. Do you have any info or maybe pictures of the set up. Like wiring, size of wires and possible recommendation after the install. Like what you would do different.
 
I upgraded the charge wire from the alternator to the fuse block using 4ga thick strand cable. I also upgraded the wires from the fuse block to the battery. Pretty common modification on these cars, nothing too tricky here. The alternators bolt right onto the block, and the only real challenge is finding a way to tension them. Morrison Fabrications sells a nice adapter that lets you use the factory tensioner.

Or you can use 1) 2458K13 (RH), 1) 2458K13 (LH) and 1) 8419K12 from Mcmaster. Along with at least one jamb nut 5/16" threads. One rod end goes under the water pump bolt that holds the stock tensioner arm. The other end attaches directly to the saturn alternator case with a nut and bolt. Turn the coupling nut one way for more tension and the other way for less tension, use a jamb nut to lock her down when you like it.
 
One comment I'll leave with, is that no fing way you need all the fuel pump. A single AEM 400 would likely be overkill. For reference, my car has just 2 walbro 255 externals. I'm pushing that through a restrictive stock fuel line, fuel filter, and 2 factory hoses on a double banjo bolt. Idk what it really makes for power right now, but it made over 750 on an engine dyno, and it makes more now. It's 30-35psi, close to 80lbs/in when it's cool out, and on E85. No signs of being out of fuel pump at all.
I'd assume being in Canada you will be on gas only, and probably a 500hp or so target. 1 bosch 044 is more than enough. Even a single 255 will get it done. I assume you are doing a surge tank deal. I'd skip it, but if you have to have it, find a different pump for the pusher.

The surge tank is there more for eliminating g-force related fuel starvation that happens in the Evo 1-3. It just so happens that most of the reasonably priced surge tank kits, such as RTM's kit, come primed for 044-style pumps (which would also include the 400lph AEM 50-1005). It's going to see E85 since it's not too much of an issue to fill a drum at the border, and I'm ballparking 700 horsepower at the crank with the EFR 7670 maxed out, so a single Walbro 450 pusher pump could do it, but the only surge tanks that are built for them seem to be the ridiculously priced Radium & Nuke kits. By contrast, RTM's single 400 kit is around half the price of Radium's 450 kit, and the dual 400 kit is still over $100 cheaper. A single AEM 400 is probably very close in flow to a pair of Walbro 255s according to RealStreet's fuel pump numbers; I suppose I could run the single 400 kit and swap out the surge tanks if the setup changes ever run it out of fuel, but there isn't much penalty to going bigger on surge flow capacity in the first place, except for a few extra dollars and current draw. Buying it once is cheaper, after all.

I did some reading on the Equinox/Vue/Torrent electric steering column last night and was indeed impressed. The amperage draw looks more reasonable, but the simplicity and getting rid of the hydraulics is very appealing. Racers and street car drivers alike seem to love it, so I'm on board. De-powering the rack isn't too big of a deal and a Mirage owner here has already done it, so it's certainly possible. Thank you for bringing it to my attention.

I'm okay with either a Saturn or DSM alternator in the 135 range with the electric column. JayRacing's alternator relocation kit seems to have the option to run DSM or Saturn alternator, but I guess this doesn't matter to people who want to keep their A/C. Even with the full load from the engine/fuel/fans/steering/ignition/lights, I imagine it should keep up. I don't see much of a penalty in going with a safety cushion here either, as long as the wiring is all done to suit.
 
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