Sorry Randy, I saw this from another post of yours...
I had to let everyone see it.

VERY, VERY IMPRESSIVE.

Is that the new engine? or still the old one?
Running full slicks?

Dyno'd it yet? Damn.. those 2.3L turbos can make some power..

------------------------------------------------------------------
BTW, I finally got my Ford 8.8 rear - from an 03 GT Mustang.
Gonna be installed soon.

 

thats nice.

 

I love it, it sounds sweet!

 

Absolutly awsome!!!

 

Wow, whats he got powering that thing?

 

Whats required in the 8.8" Swap, are you going to remove the mounting points from your -SE rear end and weld them to the mustang one? Seems the me that's how its done? What are you planning to do about the bolt pattern?

Sorry to take this a little off topic....

 

It is still a all stock and very tired bottom end (if you couldn't tell from the smoke it was emitting)
I have dyno'd it a few times now trying to get the tune a litle closer before I stick a good motor in. So far the best has been 421hp at 5700 and 440ft#'s at 4600rpms. Next trip to the dyno I'm going to mess with the cam timing a little bit to try and get the peak hp numbers a little further up in the rom range (and hopefully more too) and try to get the torque to go down a bit. Sounds odd, but that much torque at those low rpms is creating some serious cylinder pressure. Would much rather rev it harder and make a few more hp.

I'm sure there is more in it, just need bigger injectors as the 72# ones I have in there now are going 100% duty cycle. I will be going back to the track in two weeks, going to detune it just a tad, and hit it with a shot of nitrous. Hoping a 75 shot will get me down around 10.3-10.4's and if the motor stays together a 100 shot will be next.

Directfreak, your car will be a monster with the 8.8" and some slicks (I'm using Mickey drag slicks size 24.5*8/14's I tried some 22*8/15's and they where worthless and wore out quick), I was still launching at a fairly low rpm and my 60' was a 1.58.

Do you know if anybody make drag struts for a rx7? My car doens't weight transfer for anything, and having the *** end squat is horrible for drag racing.

Stretch over on v8rx7 modded a mustang spindle to work on the rx7. He is running 11" musatng disks with mustang drag struts on the front. I might end up tyring this, he has pretty much track tested it as far as I'm concerned. Talk about a quick first gen, here is a quote from his latest post.

"ran a 5.68 @123 in the 1/8th ran a 9.18@125 on the brakes hard in the 1/4

it will go 8s with ease

my head is still swollen "



Now that is damn crazy.

RX7carl, My PX7 has a Ford 2.3 turbo/5-speed drivetrain in it with a bunch of bolt-ons.



Later
Randy

 

Hmmm !!BANGGGG!! is how the rotary sounds after some abuse like that. Pistons may go boingy boingy boingy, but you can arguee with numbers. And yes I know it's very possible to get those numbers with a wankle, but they can't take as much abuse as a piston.

 

How are you tuning it? Aren't you using the stock ECU or something?
440lb-ft of Torque - is just sick.

Beside's being fast in the 1/4 mile, your car must be seriously fast on a "rolling" type race..

What PSI are you getting those numbers at?

--------------------------------
I got the 03GT Rear end with disc brakes. It came with 3.27 gears though.
I have to Narrow it down and swap gears. I don't know if I want
3.73's or 4.11's.

At least they're cheap to swap out

I am thinking 3.73's will make better use of my 1st gear, and better highway cruising.
---------------
Again - congrats on the time, and the nice ride.

 

I've just got my 8.8" back from the shop after being narrowed, and having the RX7 mounts welded to it. I've rebushed the suspension and painted the housing, and it's all set to put back in. I'm running the 10.5" rear disks and calipers from the doner Ford (1990 EA Falcon) - I was going to post up a thread here with pics and everything once it was all in place, but I can do it earlier if you want? PM me if you need advice.

 

nice run!!! rear suspension needs some sifening up!

 

I am running a stand alone unit now, Using the Holley Commander 950 with wide band input.

Boost PSI, a damn lot. On that pass it was at 30# and on the best dyno run it was at 30# also. I normally keep it at 24-25 pounds, but it only makes 410hp and 420 there. I think I am at the point where everything is becoming a restriction if that is possible. The turbo starts to drop boost in the upper rpms, the injectors are 100% duty cycle, and I'm sure the single 255hp fuel pump is getting close to being at the edge also.

I swapped out 3.73's in mine for 3.27's, but my first gear is a very low 4.02. Thats why it looks like I shift 50 feet out of the hole, I took 1st to close to 7000rpm before I shifted.
I'm surprised you had to narrow it, how much did you have it cut? With mine I am running honda offset rims and they fit perfect but I might end up narrowing it anyways. I really want to get some bogarts for it, but some 14*7 with 6" of backspacing would look horrid. If I am going to spend the casjh for some sweet rims they are going to have a big fat shiney lip on them

Later
Randy

 

What have you done to yours?
I have new shocks back there but it still squats like crazy. I think I am going to redo the suspension points this winter. They are in the stock position now, but I am thinking of raising the top rearend mount up 1" and lowering the lower rearend mount down an 1.5" to get the instant center atleast located somewhere in the car. So maybe the rear will provide some lift. I have played with the pinoin agle but it didn't make any noticable difference.

Later
Randy

 

What about stiffer springs in the back? I dont know **** about drag suspension setups so I dunno if thats gonna help or not.

 

That IS ALOT OF BOOST. I wll be Re-Dynoing on Saturday with the ported engine, and some Race Gas. I am hoping for about 400 rwhp at about 19PSI.
I'll keep cranking the boost until I run out of fuel. (Remember, I am still running a Holley CARB)

So before, you would've shifted even sooner?!

It's at least 3" inches wider on each side. I picked up an old GSL Rear end for free, so I am gonna use that one as my Guinea Pig for the brackets. That way I can keep my stock SE Rear end "just in case".

I got a nice set of 91 Mazda Convertible BBS Rims I am gonna use for a while until I put the widebody on. I also got a CP Racing Big Brake Adapter set, so I want to keep 15"s on for a while. At least I will go 5 lug all around then.

I'll be selling my current MSW rims after I swap the BBS 'vert ones on.

Do you know what the gearing is on your tranny? - For each gear?
I want to compare it to the TII tranny gearing, so I can further narrow
my rear end gearset options.

But then again, Even if my engine makes as much power as yours, it definately won't have the torque yours does.

 

4.03 2.37 1.49 1.00 0.81


I was wrong about first by .01
Pretty crappy gear spread.

Later
Randy

 

US SPEC MAZDA DRIVELINE RATIOS

*** FIRST GENERATION ***(For reference only)
……………………………………………………………….…….………………………………..AXLE..FINAL.TIRE......TIRE..ENGINE
VEH.. YEAR. 1ST.. 2ND...3RD.. 4TH...5TH...RATIO RATIO SIZE……....RPM...RPM @ 60 MPH
GSLSE 85-85 3.622 2.186 1.419 1.000 0.715 4.077 2.914 205/60-14 851...2480

*** SECOND GENERATION ***
……………………………………………………………….…….………………………………..AXLE..FINAL.TIRE......TIRE..ENGINE
VEH.. YEAR. 1ST.. 2ND...3RD.. 4TH...5TH...RATIO RATIO SIZE……....RPM...RPM @ 60 MPH
Turbo 87-91 3.483 2.015 1.391 1.000 0.719 4.100 2.948 205/55-16 828...2441
VS
Eville140...4.030 2.370 1.490 1.000 0.810 3.27

Now I see why you went with the 3.27 rear. You must also get nice crusing RPM in 5th gear. I guess I'll try the 3.73 gearing on mine.

 

UPDATE:


Well, I got my Mustang Rear End, and a spare FB Rear end yesterday.

Quite a difference between the two of them. The Mustang one is muuch
larger and heavier.

I don't know how people swap a 9" rear in there.

----------------------------------------------------------
It's getting cut and narrowed, and should be ready in a couple
of weeks.

Then it's off to the track!!

 

You have the 8.8" right? How much are you getting it narrowed?

 

Yep, I had the same thought. Most of the rx7 I have seen with 9" under them usually sit quite a bt higher if they are stock width. Or they are backhalfed cars.
I will tell you that just the extar width of the axle tubes make it a pain to get 3" exhaust over the axle.


How much are you getting it narrowed? Just switching axles could get you 1.5" inches on each side.
I'm thinking about narrowing mine in the future a few inches and putting 9" ends on it to get rid of the c-clips. A set of nice shiney bogarts all the way areounfd wure would look nice.

Later
Randy

 

You may need to be careful with the watts linkage mounting to the housing. Due to the larger "pumpkin" size, when mine was done the mounting was relocated a bit further out, which means I'm going to need to cut down the watts linkage arms a small amount, or convert the entire thing to panhard rod. I'm angling towards the former option at this time, because I won't be racing the thing around the track much, and about the only real motorsport the car will see will be over a 1/4 mile where it just doesn't matter.

I've been told the 8.8" units are good for 700+Hp, so unless you're running a large-block V8 or a 20B or something I can't imagine why anyone would go to all the extra effort (and weight) installing a 9".

 

Hey, Directfreak.... a big request

If you have a chance, can you get an actual weight comparison on both rear-ends. If you could weigh both of the rear-end set-ups... that would ROCK!!!

-Bern

 

on my 8.8 setup the weight difference over stock is 40 pounds.. keep in mind im using the largest axles (33 spline) with a light weight spool ...the areospace lightweight disk brake kit helped alot too in the weight dept.

 

how in the hell do you narrow a rear end? haha

 

Rob, do you have the actual weights? I'd like to get those #'s...

and, I'm going to guess at least 10 or so more lbs with the standard 8.8 brakes and diff.... does this sound right?


Thnks,

-Bern