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-   -   C4 auto to 13b rew quick question (https://www.rx7club.com/rotary-drag-racing-167/c4-auto-13b-rew-quick-question-747178/)

Viking War Hammer 08-18-08 12:57 PM


Originally Posted by ultimatejay (Post 8451685)
Also, Viking, I have been meaning to ask you. On your first gen that you are building for a street car. How do you plan on driving for any length of time with a tiny radiator and alcohol? I am no alky engine expert but I do know they go thru several gallons on a single 1/4mile run.

Just a FYI, ran the car yesterday for an hour. With the car sitting in the garage and the waterpump running. The coolant temps were a steady 110F the entire time. The fan never kicked on.

ultimatejay 08-18-08 11:24 PM


Originally Posted by Viking War Hammer (Post 8474323)
Just a FYI, ran the car yesterday for an hour. With the car sitting in the garage and the waterpump running. The coolant temps were a steady 110F the entire time. The fan never kicked on.

Cool.

13BT_Starlet 08-19-08 11:31 AM


Originally Posted by ultimatejay (Post 8476089)
Cool.

Hey , Jay BUMP ! :lol:

ultimatejay 08-19-08 11:42 PM


Originally Posted by 13BT_Starlet (Post 8477071)
Hey , Jay BUMP ! :lol:

:lol: , Oh man don't get me going on that noob again. What a dueche bag. I think he bumped like three or four fresh threads yesterday. :wallbash:

13BT_Starlet 08-20-08 12:30 PM


Originally Posted by ultimatejay (Post 8478919)
:lol: , Oh man don't get me going on that noob again. What a dueche bag. I think he bumped like three or four fresh threads yesterday. :wallbash:

I think more than that , He ended up with like 12 post . I guess thats the only way he can get them up since he has nothing to say or don't know what to say do to the fact he doesn't know anything :hahaha:

Viking War Hammer 08-26-08 12:26 PM

The converter shop sent me a HUB to do the measurements but we figured out that it would be easier to get a measurement from a converter that's already done. So, thanks to 13BT Starlet, we found out the stack height is 6.250 :)

Viking War Hammer 08-26-08 04:43 PM

alright, I got the converter and it's on it's way to Dirty Dog Performance

sk8world 08-27-08 02:56 PM

Get this shit done and proven so I can just copy you.. LOL..

Viking War Hammer 08-27-08 03:21 PM

Heck, the Aussie guys have already proved that this transmission works fantastic

Viking War Hammer 09-03-08 03:03 PM

1 Attachment(s)
Dirty Dog Performance now has my converter. He's going to start on it tonight.

I gave him my old Dyno Graph to go off of. I know it's going to be different than my new setup, but I figured it would give me a good start.

He's going to build me a 8 inch converter and based on the graph, recommended me go with a 4600 converter. What do you guys think?

Here is the dyno graph I sent him.

Attachment 705084

rotaryengineering 09-03-08 03:38 PM

Converter
 
When I built my converter for my car several years ago it took a couple of tries to get it right. The builder was a company called PTC in Alabama by a guy named Kenny Ford. We ended up building a 7" converter for my drag application which was setup to lockup 100% between 5500/6500. It actually started to engage at 3000, but definitely not streetable. Sounds like your making some good progress on your setup. Automatic is definitely the way to go it is much easier on the drive train than the clutchless transmissions and very consistent on the track.

Good Luck

Viking War Hammer 09-03-08 03:44 PM

I had asked him about going with a 7" converter but he didn't know of a 7" core to use. So, we decided on a 8".

I emailed him back about the 4600 converter, wanted to know if it's going to lock up at 4700. So, we'll see what he says. I don't expect to get it right the first time.

Did you end up finding a buyer for your old setup?

rotaryengineering 09-03-08 04:01 PM

No just a lot of people asking questions, but no serious buyers. The crazy part is that it works really well.

The debate will always go on about which is better. These projects are FU#*ing money pits so if the tranny will save you cash on your drivetrain and get you down the track it is money well spent.

I selected the higher stall because I was running a 28X9 MT and I thought it work well and not blow away the tires.

What size tire are you running on your new 7?

Did you go with a reverse pattern shifter or did you stick with the basic?

You won't be disappointed I had fun with my car until I took it apart.

Viking War Hammer 09-03-08 04:28 PM


Originally Posted by rotaryengineering (Post 8520259)
No just a lot of people asking questions, but no serious buyers. The crazy part is that it works really well.

The debate will always go on about which is better. These projects are FU#*ing money pits so if the tranny will save you cash on your drivetrain and get you down the track it is money well spent.

I selected the higher stall because I was running a 28X9 MT and I thought it work well and not blow away the tires.

What size tire are you running on your new 7?

Did you go with a reverse pattern shifter or did you stick with the basic?

You won't be disappointed I had fun with my car until I took it apart.

I'm going to run 325/50/15's or 28/10.5/15W's. They're both the same width.

Mine has some B&M Hammer Shifter BS. Not sure if I'll keep it or not.

Let me know what you think :)

Busted7 09-03-08 05:55 PM

Eric you know i dont claim to be an expert but i think the stalls to low at that torque range, i would start at 5500 at least but i just had a 3200 and it would not launch for anything. It was like dragging an anchor!:scratch:

Viking War Hammer 09-03-08 06:08 PM

So, my old graph says my peak torque was at 5500 RPM. I hear that your stall needs to be 400-500 less than your peak torque, is this correct?

rotaryengineering 09-03-08 06:34 PM

Eric,

I would be careful with what most converter shops recommend. Majority of their customer base run V8 powerplants. The first guy I used was guessing and we were way off. The Rotary is a different animal when comes to converters at least that is what I found. It was a learning experience for Mike's Transmission in Palmdale California and PTC.

It was actually funny when Mike at the tranny shop put my converter on his test motor he hit the rev limiter before the converter actually locked up. I gave him the specs and he told me that it was a very loose torque converter. It actually worked out well once I got the 3rd converter in the car.

Good Luck
Albert

Viking War Hammer 09-03-08 06:37 PM


Originally Posted by rotaryengineering (Post 8520812)
Eric,

I would be careful with what most converter shops recommend. Majority of their customer base run V8 powerplants. The first guy I used was guessing and we were way off. The Rotary is a different animal when comes to converters at least that is what I found. It was a learning experience for Mike's Transmission in Palmdale California and PTC.

It was actually funny when Mike at the tranny shop put my converter on his test motor he hit the rev limiter before the converter actually locked up. I gave him the specs and he told me that it was a very loose torque converter. It actually worked out well once I got the 3rd converter in the car.

Good Luck
Albert

So, based on what you've been through. What would you recommend?

Viking War Hammer 09-03-08 08:30 PM

This is what my converter guy just emailed me,


4600 is the goal at which you won't be able to rev anymore without the wheels turning. c4's don't have a lockup function. I'm going to set yours up with a medium stator so if we need to increase or decrease stall we have room to change easily.

Viking War Hammer 09-04-08 12:42 PM

I asked him if that meant the car wouldn't move until 4600.

He replied with the following.


The car will move well at light throttle. Stall speed means with the wheels held the engine cannot rev over 4600 without the wheels moving.
Alan

rotaryengineering 09-05-08 11:18 AM

I would go with a 5500 stall converter
 
Eric,

Based on your dyno sheet you posted I personally would go with a 5500 stall converter. I started at 4500 and kept bumping it up because it was a slug out of the hole. But it also depends on your engine redline. We all know we can rev the hell out of a Rotary, but what is your engine redline setup for so you don't blow your motor. I don't know all your engine specs, but to keep things on the safe side I never revved my motor past 8,500 and it stayed together for a long time. Going straight up in the air is not the goal so if your new setup is making good torque numbers like your old setup you should be good with a 5500 stall.

What RPM did you launch your old setup at with a stick tranny? Probably much higher that 5500 would be my guess.

My goal was always to get a decent launch out of my car on the turbo only with a 3 step. It worked well, but I figured if I wanted a better 60' time squeezing it could bring those numbers down quickly.

Hope this helps.

K1HKSarse 09-05-08 03:46 PM

I am running a C4 behind my 13b in my back halved FD here in the UK.I have a stall speed of 5500rpm and i have found that i cannot get car to launch above 3500rpm unless i use gas.I have put a 75 shot of gas on the car which works only on launch.I am launching at approx 5700rpm with the gas on but it takes a while to build up.If i am racing heads up then this is no good,the race is lost.

Could you explain to me what you mean by 3 step please?????

Viking War Hammer 09-05-08 03:56 PM


Originally Posted by rotaryengineering (Post 8526911)
Eric,

Based on your dyno sheet you posted I personally would go with a 5500 stall converter. I started at 4500 and kept bumping it up because it was a slug out of the hole. But it also depends on your engine redline. We all know we can rev the hell out of a Rotary, but what is your engine redline setup for so you don't blow your motor. I don't know all your engine specs, but to keep things on the safe side I never revved my motor past 8,500 and it stayed together for a long time. Going straight up in the air is not the goal so if your new setup is making good torque numbers like your old setup you should be good with a 5500 stall.

What RPM did you launch your old setup at with a stick tranny? Probably much higher that 5500 would be my guess.

My goal was always to get a decent launch out of my car on the turbo only with a 3 step. It worked well, but I figured if I wanted a better 60' time squeezing it could bring those numbers down quickly.

Hope this helps.


I just emailed him back and asked if we can start out with a 5500 converter. We'll see what he says.

My redline will probably only be 8,000. I never felt the need to shift at high rpms since my car didn't make much power after 8,000.

My last motor, I had best results with only launching it at around 6500-7000. Anything more and it would blow away the tires. Even with that, it still blew away the tires.

Viking War Hammer 09-05-08 03:58 PM


Originally Posted by K1HKSarse (Post 8527898)
I am running a C4 behind my 13b in my back halved FD here in the UK.I have a stall speed of 5500rpm and i have found that i cannot get car to launch above 3500rpm unless i use gas.I have put a 75 shot of gas on the car which works only on launch.I am launching at approx 5700rpm with the gas on but it takes a while to build up.If i am racing heads up then this is no good,the race is lost.

Could you explain to me what you mean by 3 step please?????

How safe is running a 75 shot just on your launch? Have you ever broke a motor that way? When does the 75 shot shut off?

What's your 60 foots look like? Got any videos:) ?

K1HKSarse 09-05-08 04:08 PM

Car is still in the early stages so not a great deal of back up info as yet or video's im afraid.Still on my first converter at the mo.

I havent broke a mota with the gas yet!!!!!!!!!!

Shuts off as soon as i let go of transbrake button.

Best 60ft to date is 1.4 (Avatar pic) but believe there is more to come as yet.

Any ideas how i can get engine to pick up quicker on converter?

Whats a 3 step?


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