The Viper handled well but as crazy as this is going to sound, the suspension felt soft. It was fast around sweepers, hairpins and even some decreasing radius turns, but throw some tight esses or some elevation changes or both and it can become a handful in a hurry. It also felt the heaviest in those situations. Although the suspension was good in it, it *felt* like the tires were making up for some of it.

The RX-7 in comparison *felt* faster on nearly every portion of the track, except the straight aways, obviously. Initial turn-in and transitions were MUCH crisper and there's a little bit more feedback IMO.

My old Supra was nice but it wasn't great handling. It had the motor. It made ~440RWHP@16-17psi on C-14 back in 1996 which was kind of a big deal back then. I stripped everything out of it. It even had Lexan in it, an aluminum dash with Autometer guages, etc. Even with everything taken out of it, it still weighed in around 2960 with the roll cage, fuel cell and other safety equipment in there(Still kind of heavy). It also took a long time to set up the suspension. The car didn't like to rotate around corners that well so I had to really play with the suspension. I think at one point I had almost 3 degrees negative camber in the back just to get it to rotate. Tried adjusting toe but that just made the car twitchy and nervous approaching corners. God I could go on and on about that damn car. Eventually it was time to move on so I sold it and bought the Montego blue FD.

 

Says who? Who died and named you Felix Wankel and CEO of Mazda?
If it weren't such a bad engine, why are they notoriously known for blowing up well before 100kmi in most cases? Why do they require so much maintenance? Everytime I get ready to drive mine I have make sure my stock AST isn't cracked, or my coolant fill isn't cracked. I have to walk around the car while it's warming up and look underneath it to see if its leaking anything (on a 45kmi all original car). I have to listen to it and if it makes any noise out of the ordinary I have to fully inspect it. And GOD FORBID should the CEL go on I'd probably faint....
If it weren't such a bad engine, people wouldn't feel the need to swap it out, plain and simple.
People call them mullets because back in the late 70s and early 80's rednecks everywhere aspired to drive V8 powered Camaros. It became a cliche. The whole part YOU don't understand about the V8 is this little thing called torque. Everyone here says "but you can make the same amount of HP with just X.X liters!!".
NEWSFLASH: But you aren't making the same amount of torque in the lower revs.
Drive a car with comparable handling to an FD. A C5 Vette, Z06, Viper, etc. You can leave a redlight in 3rd gear in a Viper and it doesn't care, it just pulls away. Know why? Torque. Sometimes its nice not having to row a gearbox like a madman just get some acceleration out of a car. I mean I love my RX-7 and everything, but if someone wants to try me on a friendly highway roll, I have to downshift to 4th, downshift to 3rd, downshift to 2nd gear, bring the revs up to around 4700 where the TORQUE peak is, which now puts me around 45-50 mph and then i'm ready. Sound ridiculous? Because it is...

 

Just for comparison, I graphed a Bolt-On LS1 dyno chart making about 350 whp over my 13B's chart making about 360 whp. Examine the power curves. Should both of our cars go from a 40 Roll, we would be dead even (assuming this motor were in an FD with the same weight) because our power curves look nearly identical. The FD's curve is a bit longer, but it also has 4.3 gears, so that makes up for it. Those of you who might think the Rotary makes some kind of superior power curve with some legendary "top-end" should look at the chart carefully. Oh, this same LS1 sprays a dry shot and makes around 450 whp and 600 wtq all on 93 octane.

 

The torque dosnt bother me.. Actually my car spins enough as it is already. any more torque would make it even harder to get traction. The lack of troque is probably a good thing.. you could launch at 6k and not go up in smoke like a v8. and on the street the top end walks away from v8's all the time.

 

Uh oh. Here comes the "top-end" argument. Read my above post please.

 

Sorry one more thing if it is torque you want get aturbo diesel. If low end torque is what wins races and make a engine awsome your best bet will be the turbo diesel. Anyway I think I am gonna sell my GM stock as it is falling fast. Good thing for you guys in here doing swaps cuz GM is gonna need all the help it can get. If GM builds such great motors why are they not known for their reliablity...? How come people always think Honda and Toyota for reliable cars..? Well it is projected the Toyota will be the largest auto manufacture by 2010. I am now gonna go buy some Toyota stock. I agree the rotary is not the most reliable but it sure is a neat motor. There is no perfect motor either way. Its just about choice but saying your putting a GM motor in becasue you want reliablity just really makes me laugh. You need to look at Honda, Toyota or even the Mitsubshi 2.0L for reliablity. Plus those would be original and just as capable in any "street" application. Ok for real now I am gonna try and stay outta this thread and let it die. This probably should have been posted in the other engine forums anyway since both cars had other engines.
Oh ya sorry about the double posts it said I had some error so I did not think the 1st one posted and basically re wrote everything again. Anyway thats why I had 2 posts one right after the other earlier.
Later

 

Actually, this is the kills section...and according to the rules in the sticky:

"- Have fun in this section, but not to the point where people stop coming here because they fear getting flamed. Everyone is welcome here, all types of kills are welcome here. It is not limited to kills that involve RX-7's."

So it doesn't need to be in the "other engine" forum.


Also, regarding your post about getting a turbo/diesel if you want torque...thats pretty silly. Since horsepower is a function of torque...having a nice broad torque curve means that you will not only have low rpm torque, but you will have low rpm horsepower...which is what actually moves the vehicle. I guess a good way to put it would be this. Take pianoprodigy's FD and a bolt-on only LS1 FD...judging by the power, this would be a pretty decent race if both were in optimal gear. For example, both downshift and gun it at 50mph. However, lets take both cars and do the "passing in top gear" test. Lets say both cars are going 70mph, the 13b in 5th...the LS1 in 6th. Both cars roll into the gas in order to pass a few cars in the slow lane. Thats where a HUGE difference will be. The broad torque curve gives the V8 lots more low rpm horsepower so you don't have to constantly downshift and rev the hell out of it to get power out of it. This is why stock LS1 FD's are running high 11s with 1.6 to 1.7 60ft times. They have a broad power band...so its more than just making 350hp at peak...they are also making 300hp at 4k rpm. No disrespect to the rotary, I still have the 13b in my Rx7. But the 13b is not in the same league performance wise as an LS1. It shouldn't be, considering the vast difference in displacement. The 13b does an incredible job at making power for its size...however the broader powerband of an LS1 is far superior. Anyone who feels otherwise is fooling themselves.

 

dont worry be happy!!!

 

I am putting a series 60 detroit in my first gen!

 

swanny sais someone runs 1000 hp out of a stock block and crank of a eagle talon (2.0L)




Maybe v8 swap isn't for ******* <9s cars ...
most people cant afford and dont even want to make their cars that fast.
And most people dont swap motors to make their rx7 7-8 second car..they just want a better powerplant in their everyday driver

as far as making 350-600rwhp...it would be way cheaper for a v8 to get those numbers AND more reliable..and slightly better power curve

thank u

ps this argument can go on and on and on and on and on and on
this is my last post in this thread

 

I was happy with my power curve. I found mine to be quite usefull for road racing and other spirited runs. Can someone explain to me why a V8's curve would be better or worse than this (for informational purposes, don't make this thread ugly- I am trying to learn as well):



Now, I know this graph is some-what ugly. It is missing the torque output, and the run was some-what botched. But it is the only electronic version I have at this time. It was made for tuning, vs the actual finished product, and only taken to 6100 rpms (instead of 7500-8000). Also, it was shifted from 3rd to 4th gear in this run, thus starting in 4th gears RPM band very late. When I re-dyno this spring, I will get a clean run with all numbers and a low rpm starting point. But for analysis purposes, this is what I got.. I have heard arguements where you don't want it to flatten out, and some that you do.. Thoughts?

 

BTW, here is what the RPM to HP converts to from speed:

RPM: 3,769 RPM: 4,092 RPM: 4,307 RPM: 4,576 RPM: 4,845 RPM: 5,437 RPM: 6,175
RWHP: 195 RWHP: 300 RWHP: 400 RWHP: 500 RWHP: 560 RWHP: 600 RWHP: 628.8

And the peek torque equates to: 535 ftlbs at 6175 RPM.

 

The power band on a 20b is a lot broader than that of a high horsepower 13b. I would be interested in seeing your curve (one that would include tq and rpm) side by side with a 6xx horsepower LS1 curve. It would be interesting to see the differences. The torque defficiency wouldn't be as much as it would be with a 13b. Also, I'm curious as to the amount of money invested in your 20b project. Your car is badass without a doubt...however I think your budget exceeds even the twin turbo hinson project that is in the works. I could be wrong though.

 

My budget is very difficult to calculate. I had to build this car twice, for the first time it was stolen near completion. So the money I have invested is off-base on comparison. The overall conversion was originally paid and estimated to be about 30k total. This included the engine, radiator, intercooler, turbo, manifold, exhaust, ecu, fuel equipment, ignition equipment, flywheel, clutch, etc. Basically the whole ball of works. In addition, I provided the dog-box transmission, chromoly axles, upgraded brakes, upgraded power plant frame, etc.

But, it never worked out that way. Between loosing it all, and having to rebuild it (and even better the 2nd time, with more expensive parts), and loosing some of the supplied equipment (transmission, axles, etc); it gets ugly.

In the end though, I am not making this conversation a cost vs efficency. If that was the case, go get a mustang and have at it. I am talking about general performance graphing based on two engines which produce comparable power at different points.

 

I hear ya...that sucks about your stuff getting stolen. You would think that something as rare as that would turn up. I would truly like to see those 2 graphs side by side. If I had to guess, the LS1 would make slightly more power on the bottom end, however it would run out of breath at about 7k rpm. So gearing would play an important role in real world performance. There's a guy on torquecentral.com that is supposed to have a 650rwhp N/A LS1 finished very soon. I'll make sure to get ahold of the dyno graph whenever he gets it posted.

 

I guess it depends on what you're looking for. Obviously you're making a TON of power. From what I understand, the flattening out means you could/should go with a bigger turbo because you're outflowing that setup; however, if you're happy with the powerband, it's not hurting anything.

Also, by your dyno chart, you shifted from 2nd to 3rd based on the MPH. Comparing a 3rd gear dyno to a 4th gear dyno is not a good way to compare powerbands. I'll look for a 600 whp V8 dyno and overlay the two charts to compare the power curves.

 

Actually Kukri, John Shepard is. If you go to www.shepracing.com and click on where it says Drag Talon it will not only give you videos of his runs, but also his spec sheet. His engine mod list is as follows:

Engine Modifications -

Stock block and crank
BJ's lightened stock crank
Ross forged pistons
Groden aluminum rods
HKS camshafts
BJ's ported cylinder head with 1mm oversize valves, titanium retainers, and double springs
Unorthodox cam gears
BJ's sheet metal intake.
Accufab throttle body
Buschur Racing race core intercooler and plumbing
Tial B.O.V.
HKS T4 manifold
HKS external race wastegate
Buschur full 3 1/2" exhaust
T4 Garret turbo built by Forced Performance
Fuel Injector Clinic injectors
AEM stand-alone engine management system
MSD DIS-2
Buschur racing coil on plug setup
Aeromotive fuel pump, filter, regulator
NX direct port nitrous system controlled by AEM
Shepherd racing custom built transmission. More info available here.



Forgot to add that Shep's Talon is a Unibody and still retains the All Wheel Drive. If you filter ~1000HP through that tranny with a Unibody weight, you get ~165-168mph traps which is right about where he is

 

So he has a stock crank and a BJ's lightened stock crank?

 

You'd have to ask a DSM expert on that one. I suspect that he probably lightened the stock crank a little here and there in an effort to balance the rotating assembly, but who knows.

 

No. My shifts were 3rd to 4th gear. Your math is incorrect.

Here is the gear ratio of the car:

3.483
2.015
1.391
1
.719

With a 4.1 rear end. Wheels: 275/40/17.

Here is the math chart:

RPM 1st Gear 2nd Gear 3rd Gear 4th Gear 5th gear
6300 32.4 56.0 81.2 112.9 157.1


Also, here is the video of the dyno run. Count the shifts:

http://home.comcast.net/~mhaun5/rx7/RedRx713PSI.wmv

----

BTW, I have a larger turbo on the car now. I did have a T72 "Q" Trim, Dual Ballbearing (made full boost by 3000 rpms!), with a 1.30 AR exhaust housing. I over-spun the turbo. Here is the compressor map, with my engines airflow mapped through it. Notice where it ends and the RPM shaft speed....



Here is the new turbo (dyno'ing soon):



The new one flows 10lbs/min more airflow at pretty much any given point in the map.

Anyhow, is there really a difference in low rpm vs high rpm in usage? Either application will stay in the RPM range that has the power. I guess it comes down to who has more horsepower in the sustaining time period (ie more rpms with the horsepower)?

 

Something isn't quite right there. If you made 500 rwhp at 4576rpm, that equates to 573 lb/ft of torque at the same rpm. Thats obviously more than the 535 peak that you stated. Also, if you made 560 at 4845...you would have to have made 607 lb/ft of torque at that rpm. So either your rpm's are off, or your torque or horsepower numbers are off.

 

In other words...if your torque peak was 535 at 6175...and your torque curve was relatively flat prior to making your peak, then you would be making probably around 450-500 lb/ft at 4500 rpms. This would make your horsepower at that rpm between 385 and 428, and thats being pretty generous in the "flatness" of your torque curve. I would venture that you would be a little closer to 400 lb/ft at that rpm, but I'm giving yout the benefit of the doubt. No way around it. You can't have your horsepower number be higher than your torque number until after you pass 5252 rpms. Its mathematically impossible.

 

I dont have a torque print out. I don't know the torque curve. I went to a calculator online and put in my horsepower and RPM. It spit out 534.8 ftlbs.

The horsepower is correct, I just didn't understand the calculator & torque enough..

http://www.supermotors.org/resources...timated_torque

I only input the peek horsepower (628.8 @ 6175<-- data logged, but could be off a hundred or so rpm) to figure the torque. I didn't realize the torque wasn't based on peek horsepower when I through the value in. So, I guess I can run each number through to figure it out, or does someone have a better way?

Even better for me, I didn't realize my car made over 600 ftlbs of torque.

 

I gotcha...yeah, if you only put the peak power number in, thats just going to give you the amount of torque at that rpm. In other words...your torque is tailing off past its peak...but not at a rate fast enough to drop the horsepower due to the increase in rpms. If your horsepower numbers are accurate, then your peak torque is well over 600. Pretty freakin awesome.

 

I understand what you are saying now. I just used peek power from the calc and posted that number. It is amazing though, for the torque in this car is unbelievable.