1984 RX-7 Race Car with BP! (almost a Miata) - Miata Turbo Forum - Boost cars, acquire cats.

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Old 12-21-2011, 06:27 PM   #1
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Default 1984 RX-7 Race Car with BP! (almost a Miata)

Well my RX-7 has gone through a few changes since it became a full-time race car about 10 years ago. This time around though it is a ground-up rebuild of the chassis and the drive train.

Chassis:
- 1984 Mazda RX-7 GSL-SE
- GTM Wide Body
- Ford 9" Solid Axle Rearend w/ Floating Hubs
- 13" x 1.25" Brakes all around. 6 Piston calipers front, 4 pistons rear.
- Coil over suspension all around
- SMART GT Wing

Drivetrain:
- 1995 BP Block, 84.5 Wiseco pistons, Eagle H-Beam rods, ARP studs, lightened and balanced rotating
- 1999 Head, ported and polished
- 7.25" dual disc Tilton clutch
- RX-7 TII Transmission
- BEGi Intake Manifold
- Twin-Scroll exhaust manifold (working on it)
- BorgWarner 8374 TwinScroll internal wastegated
- WeaponX COPs
- MS3 + MS3x

I am sure I am forgetting stuff here. I am adding some more recent pictures of the progress and will update/add pictures as I continue.
Attached Thumbnails
1984 RX-7 Race Car with BP! (almost a Miata)-img_0065.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0070.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0103.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0149.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0157.jpg  

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Old 12-22-2011, 10:12 AM   #2
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power goals? Looks like awesome build! Man - seeing this really makes me wish I didn't haul my '84 gsl-se to the scrap yard years ago (before I was into racing)
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Old 12-22-2011, 10:19 AM   #3
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Oh damn, this will be a fun one to watch.

The TII adapter plate is giving me wood. Don't be shy with the pictures now!
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Old 12-22-2011, 11:24 AM
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Old 12-22-2011, 11:53 AM   #4
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Very cool.

I have to ask though. Why the use of a 9" rear end. Isn't that power robbing overkill for your application? Am I to assume you had a very high powered motor in that chassis at one time?
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Old 12-22-2011, 12:24 PM   #5
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Well the power goals are 450whp with a push to pass type of deal into the 500's. I will post more picture. I have lots!
As for the rearend I was originally looking into a quick-change. However it starts to get expensive to get something that can handle that much power since I have to look into Frankland and cannot use a spool. The 9" is definitely power robbing. Originally I was looking at the 8 3/4" Chrysler, but finding parts for the 9" was much easier.
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Old 12-22-2011, 12:40 PM   #6
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Why are you going so big with the turbo? It seems like the 7064 or 7670 would be a much better choice giving you faster spool and both would still give you headroom over your 450 hp goal. They also both come in the same t4 twin scroll configuration as the 8374. Only reason I can see going so big is availabilty issues?
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Old 12-22-2011, 12:48 PM   #7
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well spool is not too much of a factor since the car will be over 4000RPM. I just want to run lower boost pressure. I don't want to run around the track at 25+ PSI to make that goal power. I would much rather make that power at 18-19PSI.
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Old 12-22-2011, 12:56 PM   #8
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Quote:
Originally Posted by bcrx7 View Post
Well the power goals are 450whp with a push to pass type of deal into the 500's. I will post more picture. I have lots!
As for the rearend I was originally looking into a quick-change. However it starts to get expensive to get something that can handle that much power since I have to look into Frankland and cannot use a spool. The 9" is definitely power robbing. Originally I was looking at the 8 3/4" Chrysler, but finding parts for the 9" was much easier.
Stop now, buy a Honda engine or SBC. Thank me later.
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Old 12-22-2011, 12:56 PM   #9
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Quote:
Originally Posted by bcrx7 View Post
well spool is not too much of a factor since the car will be over 4000RPM. I just want to run lower boost pressure. I don't want to run around the track at 25+ PSI to make that goal power. I would much rather make that power at 18-19PSI.
Why? If the turbo is in prime efficiency, who cares about MAP?

BTW, epic car and build.
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Old 12-22-2011, 12:56 PM   #10
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That makes sense. Are you building the manifold yourself or hiring somebody to make it? Looking forward to seeing the build progress!
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Old 12-22-2011, 01:16 PM   #11
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Well extra pressure means, extra issues. I have been tuning and driving turbo RX-7s and BP for over a decade. The less boost (within reason) that can achieve the HP goals, the less headaches.

I am most likely building it myself. I have definitely thought about having a Absurdflow done after I have drawn it in the solidworks since I have more room than a Miata. It will come down to having enough time during the holidays. I have the pipes and I have both flanges. So we will see!
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Old 12-22-2011, 01:18 PM   #12
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Quote:
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Stop now, buy a Honda engine or SBC. Thank me later.
Haha, yeah good idea!!!
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Old 12-22-2011, 02:00 PM   #13
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Im in love. Cool car man
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Old 12-22-2011, 02:27 PM   #14
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Quote:
Originally Posted by hustler View Post
stop now, buy a honda engine or sbc. Thank me later.
ls1
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Old 12-22-2011, 02:27 PM   #15
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It had to be said....


This is a truly sweet build. Subscribed.
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Old 12-22-2011, 02:34 PM   #16
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It is as much fun building the car as it is racing it!!!
Attached Thumbnails
1984 RX-7 Race Car with BP! (almost a Miata)-168026_10150402441595471_852300470_17116302_5841103_n.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-180534_10150402441760471_852300470_17116305_3040022_n.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-208711_10150499864010471_852300470_17842160_765753_n.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-208797_10150499863845471_852300470_17842157_2863018_n.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-227922_10150591631460471_852300470_18457375_1019648_n.jpg  

1984 RX-7 Race Car with BP! (almost a Miata)-230494_10150591631780471_852300470_18457377_7524970_n.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0106.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0129.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0143.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0154.jpg  

1984 RX-7 Race Car with BP! (almost a Miata)-img_0156.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0366.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0368.jpg   1984 RX-7 Race Car with BP! (almost a Miata)-img_0384.jpg  
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Old 12-22-2011, 02:38 PM   #17
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Quote:
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ls1
I know... too many LS-1's and LS-7's these days. It has to be different. I rather beat the Porsches in a 1.8L (well 1.9L now) than a 5, 6, or 7L engine. Plus there is something to be said about a sexiness of a 4cylinder with the turbo and all the piping. Oh well this will be fun. It was either this or a 20B (tri rotor peripheral port). Decided to put the 20B in the upcoming tube chassis!
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Old 12-22-2011, 03:20 PM   #18
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BAD-***!

Love it. I was going to suggest the v8 or honda options as well but the guys beat me to it. But it definitely looks like you know what you're doing, so either way it will turn out fast

Good luck and definitely don't skimp on the pictures
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Old 12-22-2011, 05:21 PM   #19
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I see little notches cut in the cylinder head deck between the intake and exhaust valves.

Could you explain what that is for?

Also, elaborate on the knurling in the combustion chamber, looks like it was done with a center hole punch.

Glad to see someone with a lot of experience on here.
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Old 12-22-2011, 06:11 PM   #20
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Singh grooves?
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