RotaryResurrection

iTrader: (8)

I've just spent about 4 hours reading old posts from all over this forum and it seems everyone has their own opinion. Ignition is one of the few aspects of a build I've never really had to address, but I'm at that point with my car. Short list of relevant mods:

-xs t04E, plans to run as much as 21-22psi in the future
-850/1300's with walbro
-pfc
-greddy 3 row
-coolingmist water injection to be added this week
-wideband currently indicating mid to low 10 afr's under boost, car needs retune

Plan to be in the 375-415rwhp range.

I am currently getting some breakup as you could imagine, and the WI will only add to the problem.

Money is no determining issue, but I am a fan of building a better setup for less money. Space is an issue, simplicity a plus.

The HKS twinpower has appeal as small and plug-in, but it's on the expensive side and it's merit is debateable...not to mention it still relies on stock coils.

The MSD 6a and t2 Lead coil option seems the most readily accepted setup, and is certainly the easiest and cheapest to obtain, but I am somewhat wary of using an older part...not because it's inferior, just due to age and wear alone. As an FC enthusiast for years, Im quite aware that they're robust and never fail in stock form. This is probably what I'll go with, unless someone talks me out of it.

A smaller group of people seem to like the dual crane hi6 and lx92 coils or some other dual box setup. I am no fan of 2 boxes, both for install appearance/room or price.

Anyone using some sort of 2-post coil (as an alternative to an old t2 coil) with a single cdi box?

Flames and search comments will be rewarded with smartass replies

Thanks in advance.

Howard Coleman

iTrader: (6)

FWIW i looked over the ignition options a couple of years ago and concluded that a bit over 400 rwhp or running water injection additional help was needed.

i ended up w an FC T2 leading coil and a Jacobs Rotary Pro Pak... the newer version. i talked to a Jacobs engineer before going w it as the earlier edition fried coils. i believe Jacobs has been bought out by Mr Gasket which could change the product line and support.

i have 7700 miles on the unit and am only planning to run 17 psi max on pump but run twin TO4s w 82 lbs/min so i do need a good ignition. i also plan WI this winter.

i just thought since you hadn't mentioned the unit i would. call RX7.com as they had a hand in designing it and i believe still recommend and offer it. i have had no problems with it so far and have mounted it on the frame rail close to the plugs. i run it on the leading plugs.

good luck,

howard coleman

NewbernD

iTrader: (1)

You'll be surprised how much of that breakup goes away by leaning out your tune.

I was asking myself the same questions a while ago. MSD makes a dual post motorcycle coil that a few others have run (Garfinkle I believe knows more about the unit.) I think it was something like $70. If you contact MSD support they'll be able to recommend it to you.

That said, I use a T-II coil and msd 6a. I'm sure it's far from the best solution but it was cheap and gets the job done. I do wish the MSD box was smaller though.

Bacon

iTrader: (12)

sub-zero posted this in my thread "I run MSD 6a with a twin post MSD motorcycle coil for the leading.
I use an MSD Dis 2 with 2 MSD Blaster coils for the trailing.

The twin post coil is a great coil and very hot.

You could run two MSD 6a on the leading and two Blaster coils instead. I used the MSD universal set and you could make two sets out of it."

https://www.rx7club.com/showthread.p...6&page=1&pp=15

sub-zero

Here it is if interested. I have zero breakup and run fairly rich.

www.prfactorystore.com/Detail.bok?no=15

RotaryResurrection

iTrader: (8)

Thanks. What makes that better than this one for half the price?

http://store.summitracing.com/defaul...=egnsearch.asp

sub-zero

If You hang on to your spark plug wire and crank it, you will find out the difference between those coils and the twin post. I use those for the trailing and am sure they would work fine for the leading. Search for posts from Gordon Monson who was one of the first guys to go with a single.

When I was checking my spark after I installed these the twin post spark made a insane pinging noise from the discharge it was so hot. I made the mistake of touching it . The Blaster2 coil discharge from the plug was not as hot.

This could be that I am using two different boxes for the leading and trailing. If You want to save money then go with the twin post and only one box. If you want to buy two boxes and two coils for the leading that would be the best . I was running out of room for all this stuff and the twin post mounted nicely under the upper IM.

RotaryResurrection

iTrader: (8)

But they are both MSD and both twin post coils. I see no voltage listed for the motorcycle coil you posted, but the one I posted is 40,000 volts which is in line with all of msd's other coil offerings.

http://store.summitracing.com/partde...=KeywordSearch

I dont doubt that your coil will work; I'm asking why it would work better.

EDIT: This page lists the voltage for the motorcycle coil at 40k as well. What makes it better, other than being slightly smaller?

http://www.mpsracing.com/products/MSD/ig02e.asp

sub-zero

I am not sure if that is a twin post you better double check. A MSD 7 series ignition box is very pricey so I would check that also. I am not saying that it is better, it is all I have used and works good for me. From looking at a large pic I can only see one post.

RotaryResurrection

iTrader: (8)

Looks like a 2 post to me...

RotaryResurrection

iTrader: (8)

It would be awfully nice to know the voltage output of an FC lead coil...

sub-zero

I am looking atthe wrong pic. I have never seen that coil and am sure it would work fine or even better. I was looking at this coil.

RotaryResurrection

iTrader: (8)

There are differences in the impedances of both coils (motorcycle vs the one I posted) as well as the windings. Wonder how that would impact it's use on our cars? Perhaps the motorcycle coil responds better to high rpm's?