This is a good idea for those of you who have no speedo

I drove my new rebuilt motor to 90 the other day. It now has 900 miles on the rebuild. Keep in mind this may differ since I am a 13b and have s4 rotors, housings, and RB lightweight flywheel.
Here is what I found

My GSL-SE in 5th gear
50 mph = 2400 rpms
60 mph = 2900 rpms
70 mph = 3400 rpms
80 mph = 3900 rpms
90 mph = 4400 rpms

so at this rate here is what the car should be able to do if everything was perfect.

100 mph = 4900 rpms
110 mph = 5400 rpms
120 mph = 5900 rpms
130 mph = 6400 rpms
140 mph = 6900 rpms
150 mph = 7400 rpms

I will find out when the car hits 1500 miles on the new motor.
At that time the complete suspension will have been rebuilt and new tires put on.
Has anyone done this before? Post your findings if you would.
Interested to see the difference.

 

Here was some in 4th gear that I wrote down

40 mph = 2500 rpms
50 mph = 3200 rpms
55 mph = 3500 rpms

 

Watch out Chad those spring hill Police are Ruthless!!!... You need a red stripe licence plate........lol.

 

RRTEC: Sorry to hear about Plus Mark. (I'm in Greeneville, TN) I haven't worked there in over 5yrs though but know ppl who do still.

Concerning this thread, cool theory but I think you're gonna run out of HP before ever getting to 150. It's cool to know mine will do 70mph in 3rd (not even redline) and like 95mph in 4th (not redline) Never got more than 120 in 5th...

 

I-81 and I-40 driving of course

 

[QUOTE=Concerning this thread, cool theory but I think you're gonna run out of HP before ever getting to 150. It's cool to know mine will do 70mph in 3rd (not even redline) and like 95mph in 4th (not redline) Never got more than 120 in 5th...[/QUOTE]


Basically I have the series 4 motor minus the MAF. I had my stock GSL-SE to 130 and my stock 86 SE to 130 also. I figured with the 1st gen being a little lighter I should hit 130 easy and hope to hit 140 (interstate of course)
Just want to hit it once to say it can do it.

 

At that speed its not about weight anymore. Its the aerodynamics that kill the top speed. The 1st gen is a smaller car and therefore has better aerodynamics than the 2nd gen. I think 140 is achievable in a 1st gen with a 2nd gen 13B.

 

Fire85GSLSE:

Becareful of course, but keep us posted on this. I'm interested in the results...

What's the S4 got on the 13B in the GSL-SE?

 

Better aerodynamics? Really??

 

HP, torque, tranny gears, third member gear, tire size ( height ), coefficient of drag, temperature, elevation, wind speed and direction, weight... what am I missing ?

Hey, my gears and tires combo is such that 8000 RPM in third gets me 107 MPH !!!

I like it. I like it alot !!!

But 5th is useless except on flat highway.

 

Well lets see, the stock S4 produces more hp than the stock gsl-se.

The rotors are lighter the housings have bigger ports (the motor is easier to come buy for parts to rebuild) it also will allow you to run two more injectors if you have the cash.
Well, since your in East tn ask kevin Landers. He is in Morristown.
He built my motor and I have almost 900 miles on it now with more power than I had.

 

The 5th gear in my GSL-SE can be used to pass with. around 50mph if you need to stomp on it it will go. I remember in my 85 12a 5th did nothing but drive me crazy.

 

When you drop in the s4 motor into your GSL are you gonna run carbs or go FI?
If you can get the stock s4 ECU and run the 4 injectors this is the setup I wanted to run.

Stock s4 ECU (don't have)
Stock s4 MAF meter (don't have)
Stock S4 coil packs (don't have)
Full RB streetport dual exhaust (have)
upgrade the secondaries injectors to 720cc's (Gonna upgrade mine to 820cc since I am only running two)
add an e-fan (have)
a cold intake (have)
RB Lightweight flywheel (have)


I think you should lay down 200hp easy at the rear wheels with this setup.

 

Well, MY S4 is an '88 engine to be exact. Its a streeported engine that dyno'd at 150 hp at the wheels, or so the last owner claimed. Its using stock S4 ecu, coil packs, cone air filter on MAF, e-fan, no emissions, and (I think) a pacesetter header with 3" exhaust. It uses stock injectors. I say I think about the header because I don't know for sure. It doesn't say RB on it, and the header tubes look pretty much the same. Deffinately not same length like RB ones. The engine came in an 84 GSL that I picked up for $700. I know for a fact that there is a lot of hidden horsepower in the engine, I just gotta find ways to let it out. I think I can hit redline in 5th with the car when its done, but I don't want to try because the car feels light enough in the front end at 70, let alone 150. I currently don't have ANY front air dam. I took off the piece below the bumper cover because it was damaged from curbs and my oil leak.

As for the aerodynamics of the 1st gen, I would be willing to bet that they are better than the 2nd gen.

 

Don't get me wrong, the LOOKS of the 1st gen is WAY better than the 2nd gen (IMO). But, I seriously doubt Mazda engineers would back track on design. Meaning, with each new model of the Rx-7 a more aerodynamic body design is used. If I'm not mistaken, there were ads back in 86 advertising such a thing so that 1st genners would by 2nd gens.

No doubt the S4 has more HP. But just how much more? I didn't think it was really all that much. I would be surprised a man could get 200RWHP w/o a turbo or at least a monster carb setup. I know the S5's have light rotors and such and got like 160HP stock.

Don't know how hard an S5 is to come by, but this is the motor I would want to drop in mine if I knew I wasn't going turbo. Stock redline on S5 is at 9k rpm, so I imagine streetported would take it to 10k redline with no worry. That would kick!

 

"Aerodynamics" is really based on two things. The drag coefficient, and the frontal area. A car that has more frontal area (essentially, the area a cardboard cut out of the front view of the car would take up) has more drag than a smaller car with the same drag coefficient.

Now, looking at the shapes, there is not too much difference between a first gen and a second gen. 2nd gen may be a little better at the front.

And weight plays a huge factor in top speed. Remember: Force = Mass × Acceleration. Acceleration = change in speed / change in time. So, in order to change your speed, an acceleration must occur. In order for an acceleration to occur, you need a force.

Your engine makes X horsepower. At low speeds, aero drag, bearing drag, tire friction, etc, are all small, so pretty much all of X horsepower is used to accelerate the mass of your car. As you get into higher speeds, more and more of X goes to overcoming all of the parasitic losses. You stop accelerating when the parasitic losses bet very close to X. However, as the Parasitic Losses approach Xl, there is less available power to accelerate the car, so the amount of mass that needs to be accelerated becomes more and more important. You can accelerate longer, and thus achieve a higher top speed, if your car is lighter.