Project RX7 Race car - Progress so far!

[Jenn]

Jenn, the car looks GREAT! I dunno abt that foam roll bar padding tho...

It's proper foam padding. I know there's SFI rated stuff available, but not available at our local shops. This is the stuff that everyone uses around here. It's just club racing after all.

 

[aMaff]

I know it's the foam roll bar padding, but at least the 1s that you could possibly hit, I'd go w/ the SFI stuff.

My .02. Other than that, she looks great. What condition's the motor in?

 

[Jenn]

I know it's the foam roll bar padding, but at least the 1s that you could possibly hit, I'd go w/ the SFI stuff.

My .02. Other than that, she looks great. What condition's the motor in?

Motor is awesome. Was built on an engine dyno to run N/A 285 hp (we found out after talking to the builder on the last race weekend). Ran one lap of the track before we got it. We had an issue on the weekend, but it seemed to be an issue with the Emulsion tubes in the carb (yes, carb'd 13b -- weber DCOE side draft carb on it). Now it revs right up, but we'll see how it works in testing next Wednesday night.

So the engine now has about 13 laps on it after the weekend.

 

[chuyler1]

Gorgeous!

 

[iLisa]

looks good Jenn!

 

[aMaff]

Motor is awesome. Was built on an engine dyno to run N/A 285 hp (we found out after talking to the builder on the last race weekend). Ran one lap of the track before we got it. We had an issue on the weekend, but it seemed to be an issue with the Emulsion tubes in the carb (yes, carb'd 13b -- weber DCOE side draft carb on it). Now it revs right up, but we'll see how it works in testing next Wednesday night.

So the engine now has about 13 laps on it after the weekend.

I have someone also building a carbed 13b who may want to have a couple of words with y'all

285 NA, that's bitchin. But it's powered by magic triangles, so it probably has about 90 lb/ft of torque right? jk

 

[Jenn]

I have someone also building a carbed 13b who may want to have a couple of words with y'all

285 NA, that's bitchin. But it's powered by magic triangles, so it probably has about 90 lb/ft of torque right? jk

We always says it's not powered by internal combustion, it's powered by black magic and voodoo. lol

Anyway, it has a REALLY agressive bridge porting job, and turbo rotors in an N/A case. I think that's the secret. Also, I can provide some preliminary jetting numbers if they're using a Weber and roughly the same set-up.

And make sure they use an 81-84/85 distributor system, and not 79-81. The newer one is electronic, the old one is points.

 

[aMaff]

I'm pretty sure that they're still working out the details for converting it to a weber carbed setup, so that should be handy info. I'll point him here

 

[Jenn]

At a car show in April:

 

[Jenn]

I'm pretty sure that they're still working out the details for converting it to a weber carbed setup, so that should be handy info. I'll point him here

We run a Weber 45DCOE on a Racing Beat intake manifold adaptor piece. In the carb, we have the following:

Emulsion tubes: F16
Main jets: 210
Air jets: 170
Accelerator pump jets: 55
Idle jets: 65f9
Venturis: 45
Chokes: 40

I had F11 emulsion tubes in it but it was shooting 3 foot flames out the exhaust and bogging under load.

I put the F16's in it, and the flames are now only 6-8 inches out of the exhaust, and it revs right up under load, which means the mix is about right.

 

[Shadow102]

myself and velocifero are the ones Maff is talking about in reguards to needing carb and ignition help.

Unfortunatly we are using a racing beat holley setup so i have a 600cfm Holly 4brl double pumper sitting here. I rly need to get the carb to a guy at the mazda dealership who has done it before.

As for the igntion: how are you running the ignition setup? we do have an electronic dizzy already but have no plans on running the wiring harness and such just to reduce weight and mess.

And those HP numbers are rly exciting. Its more than i was expecting to get out of the engine we are running. Its got a j-bridge port, 91 rotors, mazdatrix carbon seals and the holly 4brl racing beat kit among the other stuff. BTW what are you reving your engine to?

 

[Jenn]

myself and velocifero are the ones Maff is talking about in reguards to needing carb and ignition help.

Unfortunatly we are using a racing beat holley setup so i have a 600cfm Holly 4brl double pumper sitting here. I rly need to get the carb to a guy at the mazda dealership who has done it before.

As for the igntion: how are you running the ignition setup? we do have an electronic dizzy already but have no plans on running the wiring harness and such just to reduce weight and mess.

And those HP numbers are rly exciting. Its more than i was expecting to get out of the engine we are running. Its got a j-bridge port, 91 rotors, mazdatrix carbon seals and the holly 4brl racing beat kit among the other stuff. BTW what are you reving your engine to?

I don't have much experience at all with the Holley Carbs....love the Webers, so simple. However, our engine builder said when he did it, he contacted Racing Beat with the information on how the engine was built and they provided suggestions on jetting.

Basically, the ignition set-up is as simple as possible as it's a race car. The wiring was all custom done, no stock harness. We have a switch to send power to the ignition system. As far as I can figure out, there's a little resistor or something that is tucked in behind the distributor.

So the distributor is where the crank angle sensor was, and it's just a stock FB set up, using FB coils. You have the wires going from the ignitors to the coils, then coil/dizzy wires going to the cap, then plug wires going out to the plugs.

There's also other options for doing this (the Mallory 6al), but we're still sorting out timing issues with it so we've bypassed it for now. I will let you know how to do it when I figure it out.

I'll take some pics when I get home if I get a chance.

And we rev to 8,000 and can go as high as 8,500 as an absolute upper limit. Power is between 6,000-7,800.

 

[mazpro]

car looks really good (thumb)

 

[Shadow102]

I don't have much experience at all with the Holley Carbs....love the Webers, so simple. However, our engine builder said when he did it, he contacted Racing Beat with the information on how the engine was built and they provided suggestions on jetting.

Basically, the ignition set-up is as simple as possible as it's a race car. The wiring was all custom done, no stock harness. We have a switch to send power to the ignition system. As far as I can figure out, there's a little resistor or something that is tucked in behind the distributor.

So the distributor is where the crank angle sensor was, and it's just a stock FB set up, using FB coils. You have the wires going from the ignitors to the coils, then coil/dizzy wires going to the cap, then plug wires going out to the plugs.

There's also other options for doing this (the Mallory 6al), but we're still sorting out timing issues with it so we've bypassed it for now. I will let you know how to do it when I figure it out.

I'll take some pics when I get home if I get a chance.

And we rev to 8,000 and can go as high as 8,500 as an absolute upper limit. Power is between 6,000-7,800.

ok sounds great i was just wondering what i should be using fora redline in the car. And the ignition does seem pretty simple i guess i may be making it more complicated than it has to be. But yeah pics of the ignition system would be great if you could get them. Thanks

 

[Jenn]

Oh, and they removed the oil metering pump on the car too, and the timing is different.

OMP is gone because it once developped a leak and blew an engine. Now we just use premix and leaded fuel, it's safer that way haha

The environment loves us.

 

[Jenn]

Car is going in for alignment, camber and corner weighting today with one of the best mechanics around here (he crews in the MX5 Cup as well)!!! (eekdance)

 

[mikeyb]

Hey Jenn, Nice project car.

 

[aMaff]

hehehe I just saw your avatar Jenn. Nice (first)

 

[R2s99zoom]

haha nice! just saw the thread from your link to the RX section

I keep drawing similar triangles w/painters tape on our 7. And my dad keeps ripping them off... ehe

We're also building our '87 for track use in mind... tho there isn't much in the way of open-track events in our area, so we're focusing more on autocross for the short term...

I also read in the first part of the thread, someone giving you crap for hauling it behind a ranger...

http://www.rick2.net/imagegallery/main.php?g2_itemId=503

We tow ours behind the ranger to every event

 

[Antoine]

Glad I found this thread...Great pics and updates...The 7 looks clean, mean and ready for battle (2thumbs)...Are you currently racing in the TRAC series? Will you be participating in any other events and or series?

Let me know if you've got room for some mazdas247.com decal love...It would be great to have more rotary-heads on Mazda Forums...I really enjoy reading threads like this one...Thanks and keep the updates coming!