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-   -   tell me about your race ignition system (https://www.rx7club.com/race-car-tech-103/tell-me-about-your-race-ignition-system-395425/)

John Senini 02-14-05 04:11 PM

tell me about your race ignition system
 
Tell me all obout your racing igniition systems, especiall if you ar running GT2, or GT3 or CSR with a bridgport engine with carburator!!!
thanks

cpa7man 02-14-05 09:37 PM

Most of the EP racers are doing this. http://www.mazspeed.com/msd.htm

This is another alternative. http://www.geocities.com/cd23c/dlidfis.html

I'm going to do the MSD this season. You can pick up a used MSD unit fairly cheap.

BMS2004 02-14-05 09:44 PM

Paul are there any specific advantages in EP with MSD vs jeff's style of dlidfis? If you can't tell we haven't gotten that far yet

cpa7man 02-14-05 10:04 PM

Ron I have no idea which one is better. I know the guys at the front of the pack (Lemon, Prather, Rivera) are running the MSD or the stock system. A lot of the stuff talked about in the dlidfis article means nothing to us. Cold starting, low end torque, emissions. All in all you can't beat the simplicity of the stock system. The only way to know is to experiment.

Kenku 02-14-05 11:38 PM

Actually, Downing talked about ignition in the much fabled out-of-print book. He said that the advantage of CDI boxes (like the MSD) is far faster recovery between discharges of the caps vs. the coils. Seems counterintuitive, but the CDI box is only using the coil as a transformer for a brief instant, while the normal style ignition needs to saturate the primary coil and then collapse it. Ugh, I'm not an electrical engineer... to cut to the chase, he found that the longer time it took on the normal setup to recover meant that at higher RPM, the plugs were recieving *half to a quarter* the normal voltage!

Uhm, on a *cough* completely unrelated note, does anyone know how illegal it is to distribute scans of an out of print book?

John Senini 02-15-05 02:18 PM

How about spark plugs??? what is preferred, is there anything else proven out besides a 40 dollar plug!!!????

Kenku 02-15-05 02:33 PM

Well, that shows the problem of the Downing book being almost 20 years old. He reccomends the Champion N539C or N513V plugs for full out race use... but neither is in production. The first is a single point plug, the second is surface gap, and both are evidently very very cold. But neither part number is made any more, so I have no idea what they related to in currently produced plugs.

I'm really tempted to experiment with some surface gap plugs though... one consideration is that Champion sells race plugs for about a quarter what the NGK race ones Mazda specs cost. So if they work as well, yay, a cheaper solution!

Then again, we *have* the NGK plugs already... ;)

John Senini 02-15-05 02:57 PM

what is the current ngk part number for a 12 bridgeport

Carl Byck 02-15-05 03:08 PM

If you hunt on the web, the NGKs can be had for ~25.00. Carl

speedturn 02-15-05 03:43 PM

NGK worked closely with Mazda's racing department to design this plug just for bridge ported and peripheral ported rotary race engines

NGK # R6725-115 (this is an 11-1/2, very cold heat range)

Mazda sells this plug under their part number 0000-10-R115

the very cold 11.5 heat range is needed under sustained hi output road race conditions. Other, hotter plugs will work for briefer, shorter power bursts (like 1/4 mile,) but for the long 1/2 mile and 3/4 mile straights on some road race tracks, the hot plug will get too hot and cause detonation or misfiring. I too resisted the expensive plugs, but after I finally started to use them and I saw how well my motor works with them, I never race with anything else.

The -115 heat range is proven to be best for bridge ports and peripheral port road racers.

These plugs are so cold they will foul out during extended idling periods. NGK recommends, and I always start and warm up my PP race motor with cheaper hot street spark plugs, and then change the plugs to the cold -115 ones just before the race. If the motor still has some heat left in it (say 100 deg F) from a previous practice or qualifying session, then I won't change to the hot plugs for warmup.

Gene 02-15-05 04:21 PM

How do you go about safely changing plugs on a hot motor? I'm fearful of stripping things on hot parts. The torque spec for plugs isn't very high, however...

speedturn 02-16-05 09:30 AM

It is much easier to change plugs on a race rotary with all the crap stripped out of the engine compartment.

Also, GT class road racers are allowed to move the engine over to the centerline of the car, which gives even more room to change plugs.

About 30 min before the start of a race, we fire up the cold motor and warm it up. When my water gauge gets up to 160 deg F, then we shut the motor down and change over to the race plugs. We use Mechanix gloves to keep from burning our fingers. We have been doing this since 1997 when we went to PP motors and the -115 plugs, and we have never, ever stripped the threads on a spark plug.

cpa7man 02-16-05 11:14 PM

speedturn, do you recommend those plugs on an agressive street ported ep car? (12a)
I guess I should check Mazda Comps recomendations. I'm running the BREQ9's I think. Stock 3rd gen plugs.

Checked Mazda site, they recommend stock 3rd gen plugs or the racing plug, I see their available in several heat ranges. Mazda price is $29.50 ea.

speedturn 02-17-05 07:58 AM

For an SCCA E Production engine, I would try the slightly hotter -105 plugs instead of the colder -115 plugs.

yelwoci 03-04-05 12:41 PM


Originally Posted by speedturn
NGK worked closely with Mazda's racing department to design this plug just for bridge ported and peripheral ported rotary race engines

NGK # R6725-115 (this is an 11-1/2, very cold heat range)
.......Cropped.....
These plugs are so cold they will foul out during extended idling periods. NGK recommends, and I always start and warm up my PP race motor with cheaper hot street spark plugs, and then change the plugs to the cold -115 ones just before the race. If the motor still has some heat left in it (say 100 deg F) from a previous practice or qualifying session, then I won't change to the hot plugs for warmup.

I do exactly the same on my 12A racer.
I actually start on some NGK 6EPs designed for VW Polo's, but never drive the car on them. get water temp to 85C and swap them out.
No problem with stripping since the start-up plugs are barely hand tight and the race plugs go in with a torque wrench and as is said elsewhee on a racer all's stripped out so plenty of room.

diyman25 03-05-05 01:43 AM

on my IGN system

I have MSD 7al-2 on my leading side, and 6al on my Trailing. hook up in tradional way. also have 2 MSD coil.
on MAZDA TRIX E P race car. they have two 7al-2 on leading and trailing


I constant change plugs on my 13B PP. I use cheap bike plugs during warm up, and using 10.5 NKG racing during race.

Change the plugs is never be easier on PP engine, It will took me less than 5 min to change all the PLUGS

Carl Byck 03-06-05 12:36 AM

Properly tuned the 11.5s will not foul. I can start my car on a 35 degree morning, let it idle up to temp, and drive away. I have an E6K, 3- MSD6A, and stock TII coils. Carl

diyman25 03-06-05 12:42 AM


Originally Posted by Carl Byck
Properly tuned the 11.5s will not foul. I can start my car on a 35 degree morning, let it idle up to temp, and drive away. I have an E6K, 3- MSD6A, and stock TII coils. Carl


YEp you have EFI ;). you will foul your NAG racing plugs for sure. if you are runing Race CARB set up.....


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