LETHAL RX7

iTrader: (1)

I was wondering if anyone has a two step on there car and how its hooked up and what i need. i want to go to an msd system and i would like to get the two step hooked up before we start running around here...its a 93...street port t78 yadayada.. just wondering what it all intales..i have hooked them up on other cra sjust never a rotary..i appreciate any help

crispeed

You need to connect it to both leading and trailing and all the MSD boxes involve. So if you're using three boxes then you need three, two-step controllers. If you're using the later DIS boxes then they have them built in! You can either use a hand operated switch to engage it or like how I have it done a switch on the clutch pedal.


crispeed
87TII
9.20@150mph

LETHAL RX7

iTrader: (1)

thanks for the help

peejay

what if you rigged the clutch switch to activate just a two-step on the leading ignition and completely kill the trailing? just run the trailing ignition's power through a normally-closed relay and the clutch opens the relay. that way when you're staged it only runs on leading ignition, you don't have to worry about the separate rev limiters working out of phase and accidentally fire the trailing only (i've heard that's bad w/turbo). then when you dump the clutch the trailing comes back on-line.

it would also be good for those of us who don't have clutchless trans yet... just keep the loud pedal down and don't worry about overrevving it or dumping the clutch at super-high revs in the next gear - the 2-step/trailing kill would make revs fall to whatever the 2-step's set to. i'd personally want to use 5500 for the two-step limiter, 'cos that's close to what I launched at and where my revs would drop to on the upshift - perfect!

waynespeed

I wanted to try out the MSD DIS 4 using four channels, a friend of mine told me that the DIS 4 would not work with the short interval between the leading and trailing plugs. Any truth to this?

crispeed

I originaly did it like that for the same reasons but I use to foul plugs often and after noticing all my buddies using both with no problems I did the same. Never had a problem as yet. Some people use 4 boxes with 4 two steps with no problems.
BTW. I dont have a clutchless. Still have to use the clutch

crispeed
87TII
9.20@150mph

crispeed

No experience with that set up. You know how it goes. One way to find out!

crispeed
87TII
9.20@150mph

Roy Johnson Jr

I am running the Power FC w/Datalogit software. I've been told that it has a two step built in. Is there any truth to this? If so, where is it manipulated and how?

On a second note, I'm running the HKS twin power ignition upgrade. What can I do to create a two step with this setup?

TYSON

True. I asked MSD.

enzo250

DIS units need to have ~60 degrees seperation between channels. Can't be used on rotaries!!

You'll need two DIS-2's / or one Digital 6 and DIS-2

LUPE

crispeed, wanting to hook up my two step. I have a msd 6al hooked up to my leading. I also bought a 2 step with adjustable dial.

How can I hook this up?

Roy Johnson Jr

Which two steo did you buy?

LUPE

I bought this RPM Selector MSD-8672


I bought this two step MSD-8739


Hopefully crispeed will respond.

crispeed

You only got the two step on the leading?

MARTIN

microtech has it built into the software... and you need 2 step on leading and trailing, unless you shut off trailing while using it.

LUPE

I haven't hooked it up yet.

I only have one ignition box (6al) and it's on the leading. I know how to hook the 2 step up to the leading but, I don't run a aftermarket ignition box on my trailing. Is there a way to hook the two step up to my trailing if I don't have an aftermarket ignition box?

Thanks bro.

Roy Johnson Jr

How much boost were you running when you ran the 10.74@129? I would assume this run was performed with no boost built at the line, since you just now hooking up the two step? Also, how much HP are you pushing at the wheels at that boost level?

I've heard running a two-step is rough and potentially damaging to the motor. Will you be freshening up your motor often?

LUPE

I let off right before the finish line when I ran the 10.74. I should have put up around 136mph with my 105 mph in the 8th.

Was running 23psi of boost. Here are some videos, you can see I can't drive.

http://www.weedhack.com/vids/Eric10sec.wmv
http://www.stlsr.com/downloads/Eric10sec.wmv

When steve tuned my car on the dyno, "corrected" hp was 533whp. I don't plan on rebuilding it very often, I hardly ever drive it. The motor only has maybe 30 miles on it now.

crispeed

You'll have to shut down the leading when using the two step.

LUPE

You mean shut down the leading and trailing? I have my 6al hooked up to my leading now which is what I planned on plugging into my 2 step. Can I run the 2 step just by hooking it up on the leading or does it need to be on both the leading and trailing?

Would you recommend me just buying another 6al for the trailing and another 2 step or ............hook up a switch to turn off the trailing?

Appreciate the help.

MARTIN

If you gunna buy a 6al for the trailing, then you need 2 of them..

crispeed

Yeh I meant the trailing.
Also you'll need two 6al's for the trailing and the two step/rpm selector boxes for the trailing have to operate at half the rpm of the leading so basicaly if you're two stepping at 8k rpm on the leading the trailing would have to be at 4k.

LUPE

Alright, I'll buy two more 6al's for the trailing. I will need one 2 step box for each 6al? So a total of three two steps and 3 rpm selectors?

What's the theory on running the trailing on half of the leadings rpm? Just curious

Again, thanks for the help. Not much drag racing tech on this forum.

crispeed

MSD box in 4cyl mode. The trailing is direct fire and only sees half the rpm per coil where as the leading in waste spark fires twice.
Hook a tach to one trailing coil and you'll get the idea. You would not believe how many people make that mistake and have all sort of problems with the two step some of which leads to blown motors and also the belief that rotaries don't like two steps. I've always used the two step on rotaries without any problems.
When I was running my car the two step would be engadge as soon as I'm fully staged on a pro tree which btw was mostly at 9500rpm.
Our all motor rx-3 two-steps at 10,500rpm.

Roy Johnson Jr

If set up properly, do you feel that the two-step setup damages or shortens the life of the motor?