EProdRx7

Anyone interested in a racing only alternator? I have a 6lbs. 55amp mini alt in my race car and was wondering if there was enough interest to put together some kits. I guess it could be used in a street car but not if you have a big thumping sound system. The only drawback I can forsee would be that the stock alt. plug would be unused and therefore the alt. warning light would not work. Cost would be around $300 + shipping. This is a "plug and play deal and would include everything you need to replace your heavy stock alt. Let me know if you guys are interested.

rhinor61

A stock '84 Rx-7 55amp alternator weighs in at 9.25lbs and you want to sell a 6lb alternator for $300. I am no brain surgeon but that is $100 per pound in weight savings. I think I would go on a diet to shave 3lb and save $300 + shipping. Skipping a few large meals before a race could do that.

I appoligize if I seem harsh but $300 for shaving 3lbs, what am I missing. ANYBODY???

I know of better places to spend $300, like track seat time.

reza

I think the idea is so that you can eat extra on the buffet before the race ))

EProdRx7

Hey lighten bud I'm just testing the waters here. Not trying tgo rip anyone off. I guess you answered my question and I wont be seeing your check anytime soon but just remember that these are new unused parts. Not some crap pulled off a scrap heap.

As far as cost analasis goes, this is from Carparts .com for the new parts that you mentioned. Maybe you can find them cheaper?

Alternator, Reman.; 50 Amp; One V-Belt; For Mitsubishi systems
• Subject to mfg. core inventory / Usually ships in 7 - 10 business days. BECK/ARNLEY 186-0355 $249.54 $191.99 $0.00 Each

Alternator, Reman. Repl.; 55,60 Amps Mitsubishi System, Plug Config. MI5+P, Inter. Reg.
• Subject to mfg. core inventory / Usually ships in 7 - 10 business days. BOSCH AL391X $257.50 $232.60 $0.00 Each

So apples to apples my stuff only only costs $33.33 / pound or $22.46 for the Bosch unit, plus shipping of coarse....

rhinor61

I have to agree, new parts for racing is prefered, but new parts are also not stress tested. I have seen brand new parts fail, compared to a parts that has seen 75k+ miles.

Hey if you get a chance shoot a picture of the set up, I would like to share it with my buddies that do the 12hour enduro next month. They have to at night so a good alternator is needed.

What is the turn around time for a alternator?

EProdRx7

Well if you want one I can gather the parts within a day and ship at the most a couple of days later. I just need to know what pully you use for belt size.

I'll try to take a pic asap.

I agree about the stress test. The one on my car did the entire SCCA runoffs this year without a hitch, if that is any test.

Speed Raycer

I know of at least one EProd driver who's putting his car on a diet... 3 lbs up high and forward is a pretty big deal for him!

bill Shurvinton

For a race car $100 per pound saved doesn't actually sound too bad. I'd certainly be interested.

What would be nice would be something that would combine a lighter alternator mount with an electric water pump adaptor so you could remove the whole water pump casting. Should bring the weight savings up to the 10 pound mark

Bill

DriveFast7

iTrader: (1)

I use a 1990 Turbo ][ alt. 80 amps and I always have good voltage. It's lasted 2.5 years of constant hot lapping days. I spun the motor up to 10,000 last weekend on the dyno and 9600 on the track and she took the abuse. Mazdacomp pullies.

3lbs weight savings would be nice but $300 is steep. Some peoples put Geo Metro alts on their racecars, they're small and low amp.

Another option is to ditch the alt entirely and use a 15volt battery and charge it up in the paddock

EProdRx7

DRivefast7, I spin my motor to 10K every time I shift! Realy I shift at 9600 but at a lot of tracks I need to exceed that for one reason or another. This one is rated at 50 amps and I use a small battery mounted in back of the passenger seat. I don't really like the total loss system. I saw a guy lose a race from a ten second lead this year because the generator that was charging the car between sessions ran out of gas. No one realized untill it was too late. Too much maintence... I know the cost is steep but as I said before these are new parts and not a whole lot more $ then new Mazda parts.

Bill,
I could look into removing the WP entirely but the rules I race under prohibit electric WP's. I see mounting the alt. on the plug side of the motor under the CAS. Then make up a cover with an-14 or -20 bungs to go where the WP was, mount the pump on the inner fender... You pay for it and I'll make it...
My car

bill Shurvinton

Problem is that I have a dry sump pump on the plug side of the motor so it would still have to go on top.

I'll work something out one day. Mind you I don't even know where the alternator on my engine came from as it is smaller that the standard 1st gen units. One day I will work out where it all came from.

EProdRx7

Can you run it off of the rear axle or the pinion flange?

bill Shurvinton

Not really as it has to remain a street legal car

EProdRx7

Well not sure why you would need a drysump on a street car but "to each thier own". BTW ever thought of adding an extra stage onto the sump pump to act as a WP?

To the rest of you guys would you be interested in a bolt on electric WP set up if I put one together? And how much do you think it should cost?

bill Shurvinton

Lower polar moment. The engine is in a lotus 7 replica, and as it weighs around 1250lbs moving the block down 4" is worthwhile. And it was a good deal.

I can't extend the sump pump as it would cover the front rotor plugs then. I need to think more about it.

https://www.rx7club.com/showthread.p...hreadid=212410 shows a couple of pictures of the rough install. Much tidying up needed still