1993 Mazda RX-7 with 370 cubic inch LS1 v8 engine and t56 6 speed transmission

"Daddy, what is torque?"

I bought this 1993 Mazda RX7 in June of 2005; it was already converted to LS1 power. Its stock twin turbo rotary engine was replaced with an LS1 v8 motor that was bored and stroked to displace 370 cubic inches. It has a baby "Comp Cams" camshaft with duration of 216/220 and 114 lsa. The heads and motor were built by More Performance in January 1999. The heads flow 300 cfm the on intake. The short block has Wiseco pistons, Lunati rods, and Scat 3.90" crank. Click for receipts/parts/pics/engine dyno results of motor.
When this motor was in the previous owner's camaro in 2001, it went:
60' ....... 1.480
330 ....... 4.482
1/8 ....... 6.968
MPH ....... 98.83
990 ....... 9.044
1/4 ....... 10.90
MPH ....... 124.84

Click here to view the modifications I have done.

Reliable Carriers transported the car insured from Hinson in Alabama 01/05. Previous owner did not drive the car more than 20 miles since the conversion. THEN I BOUGHT IT.
Stock curb weight for a 5 speed base model is 2789 lbs, with approximately 50/50 weight distribution (click here for actual weight of my car). The brakes have Power Assist, ABS standard, 11.6" 4 piston ventilated front rotors and 11.6" ventilated rear rotors. However for this conversion, ABS has been deleted, along with AC and PS.

This shows the Hurst Line-Loc and the Summit brake proportioning valve (update - prop valve removed 7/06 Click here )

Click here to see various other shots (underneath, rear, driveshaft, torque arm, exhaust, gas tank, etc.)

7/13/05 - Cartek tunes the RX7

When I first got the dyno numbers, I was very dissappointed. But a few hours later, the previous owner (Mickey) faxed me the cam card:
.523/.530 lift!! 114 lsa 216/220 duration. I had no idea the cam was that small. The motor was built in january 1999 and put on an engine dyno in febuary 1999 and it made 474 hp.

My B1 cam in the firebird, which was considered a baby cam had .558 lift. So you can see how small the rx7's cam is in comparison.
Cam in firebird was also 221/221 duration, where as the cam in the rx7 has duration of only 216/220.

To compare, my firebird formula with Cartek heads and b1 cam made 387 tq; one ft-lb. less than what this rx7 makes now. And the RX7 is 600 lbs lighter. Julio did his tuning magic and got rid of the KR I was getting and set the rev limiter to 6600 RPM. Dave also helped find the cause of a squeak; the throttle-body was ported but the two holes in it were sealed....he drilled them open again and no more squeak/hissing.

Click here to view the first dyno graph.

I had Mufflex install a 3.5 inch bullet muffler in front of the hooker aerochamber muffler to lessen some of the drone. while under the car, Denny noticed a brace was missing bolts on the left side but still bolted in to right side (sort of like the tunnel brace of f-body but this is not flimsy stamped steel, its cast and is sturdy). left side holes were stripped so they tapped them and got it nice and tight. another great local shop!

7/15/05 - Building the Beast - Pictures of the build up. Car stripped to bare metal, soda blasted and painted "Electron Blue". Brian Hinson of Hinson Supercars emailed me the pics he took during the build up. Click here for pics.

Click here for the cost of the conversion, excluding motor/tranny/car.

8/19/05 & 8/20/05 - Pocono Open Track Event - Hosted by PDA. Click here for pics, video and info.

9/17/05 - Steering bolt in backwards

I was looking for where my brake fluid was leaking when Tom X noticed the bolt that goes in the steering shaft (near the firewall) was loose. There was no nut on it or we were thinking the bolt was too short to even use a bolt on it.

So I took the bolt out and I realized that no nut is needed because one side of that shaft is threaded. The problem was the bolt was in backwards and was going into the threaded part first; it would never get tight that way.

Here is the before picture; see bolt exiting on yellow unthreaded section

Here it is fixed. bolt reversed (start the bolt on yellow unthreaded section)

Pretty basic but maybe will help someone.

9/18/05 - Another RX7 with LS1 gets magazine coverage

Sport Compact Car Magazine with the "Ultimate Street Car Challenge" competitor Mark (GNX7) and his 1993 Rx7 with LS1. Click here.

9/25/05 - Leaky Master Cylinder

Tom X helped me change the Master Cylinder because it was leaking. Got new one from autozone for $80 with lifetime warranty.

10/12/2005 - Dyno Session uncovers Low Fuel Pressure - Compared to last time it was dyno'd, it gained 11 hp and 9 tq (better weather?), but it is not maintaining 56 lbs of fuel pressure. The fuel system is from HINSON and should be able to support current power levels:

The cause of the issue is that the fuel pump is not getting adequate voltage. After the fuel pump connector, I see 11.3 volts at idle and 10.9 at WOT at 6000 RPM.. That is too low. So i bypassed the connector, and now i see 12.2 at idle, but it drops to 11.5 at WOT at 6000 RPM, which is still too low.

A/F ratio was up to 13.8 on the dyno due to the low fuel pressure (too lean). This was only at 22.5 degrees timing. i want it closer to 27 but that will have to wait until I fix the pressure issue. 386 HP and 397 ft/lbs of torque:

Click here to see dyno graph showing low fuel pressure.

Clere here to see dyno graph showing lean air/fuel condition caused by the low fuel pressure.

10/23/05 -Low Fuel Pressure - To solve the issue of the fuel pump not getting enough voltage via the stock wiring, I wired the pump directly to the battery with a fuse and a relay. Click here to see diagram of how to wire it with the relay.

The white plug for the fuel pump has 5 wires. The 3 small ones are for the fuel level sender, so don't touch them.
The bigger black wire is the neg for the pump.
The red/white wire is for the pos for the pump.
Cut the neg and pos so they no longer are connected to the white connector.
Also cut the neg and pos wires that go to the connecter; you will use that red/white to power on the relay. The neg wire you can lengthen and connect it again to neg from fuel pump (actually just bypassing that old white connector).

From the battery, run 10 gauge to a 30 am fuse holder. Then continue it to the relay (the 30 position).
From that red/white wire still connected to the fuel pump, lengthen it with more 10 gauge and connect to relay (87).
Make a small wire with spade connector to relay and crimp a circle connector and ground it to chassis in trunk (85).
Use the original fuel pump wire that is coming from the front of the car (red/white) and put spade on it and connect to relay (86)  - this is the one that turns on the relay.

10/29/05 - Corner balance and vehicle weight comparison of RX-7 with LS1 versus stock RX-7

Both cars had spare removed. Both had almost full tanks of gas but my car has a reduced capacity tank which holds 5 gallons less (5 gallons at 8 lbs/gallon = 40 lbs). Both had stock 16 x 8 rims but i had 245-45-16's Yok AO32R's and rotary had 265-45-16 Kumho ecsta v700's. My car is missing AC, PS and ABS. My battery is in bin on passenger side whereas stock RX7 has battery in original position up front. Bottom line is mine weighed about 15 lbs more but had a better weight distribution of 50.5/49.5 front to rear and his stock RX7 was 53/47:

  LS1   Rotary
Left Front lbs. 684   718
Right Front lbs. 695   718
Total Front lbs. 1379   1436
       
Left Rear lbs. 705   660
Right Rear lbs. 645   618
Total Rear lbs. 1350   1278
TOTAL Weight 2729   2714
% over Front 0.505   0.53
% over Rear 0.495   0.47

We weighed the cars at an autocross event with The M club. I'll update with official times when they are released, but my fastest time was 54.0 and his was 56.0. His tires were way better than mine, no comparision. they were wider and stickier. My yok's are hard compound and are better on road courses than autocross. He is SCCA SS class driver that is original owner of the car, which is 93 R1. He races full season and competes in Kopeka, but this was my first autocross of the year!! and my first time ever autocrossing any RX7. He has stock R1 springs (stiffer than my stock non-R1 springs?) and $2400 koni custom valved double adjustable shocks and i have 13 year old stock units. The lack of ABS in my car definitely hurt my times as the video reflects constant right front tire lockup (dusty course, need new bleed because i just installed new master, need to adjust proportioning valve, who knows). He loved the car and how it felt on the course so that means a lot coming from a die hard rotary owner/racer.

Click here to watch video and to listen to RX7 owners' comments

11/2/05 - Oil Analysis - I got the oil analyzed by Blackstone Labs. Read the results here.

11/9/05 - Final Tune - Cartek retuned the car because I fixed the low voltage issue with the fuel pump. Fuel pressure was perfect at 56psi. The car made best power at 24 degrees of timing. HP is now at 398 (up from 386 last session) and 410 TQ (up from 397).

Click to see dyno graph

Click to see latest dyno versus the previous dyno (low fuel pressure, lean air/fuel ratio and 22.5 timing)

11/13/05 - Drag Racing at E-town - I only got one clean run: 11.5 at 122.5 spinning and hopping with a 1.88 sixty foot time. race weight agreed with the corner weight scales: 2930.

My second (and last) run had bad wheel hop again and caused the exhaust intermediate pipe to detach from the y pipe since it was just held on with a band clamp, so i aborted the run. Click here for pics and vid.

12/3/05 - Drag Racing at Atco

Time slip and pics here. Thanks to Tommy and Erin for raising my rev limiter to 7000. At 6600 rpm, I was hitting the limiter before the traps and only trapping at 122.5mph

After the first pass, I was expecting a warning for not having a rollbar. Nothing was said, so next pass was another all-out run hitting rev-limiter at finish line. Then I got "the talk" about how I have to go slower. So I made only half- passes for 3 laps. The short times were bad 1.67-1.74. On what turned out to be my last pass, I lowered launch RPM to about 3500 and really slipped the clutch so I didn't "shock" the tires too much. The car bogged but picked itself up pretty quickly and I was totally shocked to see a 1.578 60ft time! Thats a better short time then the formula ever got. I wonder if the car lifted a wheel at launch. I powershifted each gear, and I was really close to 7000RPM at the finish line. The mph totally shocked me at 127.2!! There is more in the car but I am not in a hurry to hit the track again; they are all closed anyway for the winter. After I got my 10 second time-slip, the track workers waved at me and said "bye bye" and that was fine for me. I wonder how much the rear diff changes that I plan on making will affect my next drag strip results (I am installing 3.90 gears to replace the 4.10's, and the kaaz differential will be adjusted from 100% to 33% locking).

  1st pass 2nd pass 3rd pass 4th pass 5th pass
60 ft 1.683 1.683 1.695 1.675 1.578
1/8 mile ET 7.265 7.208 7.231 7.215 7.098
1/8 mile mph 97.67 99.54 99.00 99.37 99.76
1/4 mile ET 11.204 11.089 n/a n/a 10.979
1/4 mile mph 119.51 122.58 n/a n/a 127.26
Comments Hot off street; 2 hr drive . coasted past finish line as to not hit limiter. little axle hop. hit rev limiter at finish line. half pass half pass New best. Raised rev limiter to 7000. Lower RPM launch, bog.

1/21/05 - Installed oil cooler and oil temperature gauge

Not needed for street driving; a must for open tracking. My oil pressure would get so low after 15 minutes of hard driving on the track in summer...oil got too hot - installed cooler and no more issues. On the street, in current setup, on a cold night, it is too cool - barely 160 degrees.

1/26/06 - I got first place for the season in the M club's Hot Laps timed trials. So what if i was the only car in class A!?!?!?! Click here for proof.

2/18/06 - Switched to 3.90 gears from 4.10's, and adjusted kaaz differential from 100% lockup to 33%. Diagram showing how to set up the Kaaz

2/20/06 - Got me some new wheels: SSR Competitions. Click here for pics.

3/16/06 - MazdaSpeed adjustable coilover shocks.

3/25/06 -Two pics from Lime Rock road course - Pic 1 - Pic 2

5/28/06 - Autocross pics and vids with Motorsports Northeast (formerly the M club). Click here

6/6/06 - Devil day (666). Interior mods (black factory leather seats and black door panels)

7/16/06 - Installed ABS system. Click here. Installed Sparco Roadster drivers seat on custom seat brackets (and some car wash pics). Click here.

7/28/06 - Autocross pics and vids with Motorsports Northeast (formerly the M club). Click here.

8/12/06 - do 275/40/17's fit on the front? 17x9.5 wheels with +42mm backspacing. Click here.

9/8/06 - Autocross pics and vids with Motorsports Northeast (formerly the M club). awesome professional pics - Click here.

10/8/06 - Mickey Thompson ET street radials (255/50/16) versus bias ply (11.5x16x16). pics

10/23/06 - Atco private track rental. drag racing pics and vids. no new best. 11.00. broken tranny mount. pics and vids

1/4/07 - Dave at Sears got my car aligned. Click here to view.

1/15/07 - Some random interior shots (very dirty) and new Boston Acoustics 6.5 inch door speakers. Click here.

1/28/07 - Johann installed custom power steering system and a new exhaust turndown/tip.

3/12/07 - Custom sway bar spacers, RX7.com trailing arms and poly diff bushings, and Kumbo v710 race tires. Click here.

3/25/07 - Autocross at Giants Stadium. Pics and vid. Click here.

3/26/07 - Falken Azenis 615's mounted and weighed; compared to Kumho v710's. Click here

4/04/07 - Took some pics at an old barn. Click here.

4/7/07 - Installed stock gas tank, Hyperion's Surge Bucket Cover, fuel pressure gauge. Click here.

4/22/07 - Autocross with the Northern NJ Porsche Club of America. Click here.

4/29/07 - Installed Hawk HP+ pads on the rears tonight, to get ready for Pocono this saturday. The passenger side rear inner pad was broken off its backing plate and stuck on the rotor. I needed a screwdriver to pry it off the rotor. Pic1 Pic2

I also zip tied the Hot Laps timer display through the center AC vents. Seems like it is in a good line of sight; might also be able to be seen on my in-car camera. Pic of timer

5/5/07 Pocono East road course with PDA. Power Steering hose leaned against header and burned a hole in it, and broke 2 valve springs and 2 pushrods. Pics

5/25/07 Autocross with Motorsports Northeast. 1st Place and FTD (Fastest Time of the Day). Pics and vid.

6/01/07 Autocross with Motorsports Northeast. 2ndst Place. Pics and vid.

7/1/07 Taurus fan and Stainless braided power steering hose. Pics.

7/18/07 Tranny mount detaches from floor. Pics.

7/29/07 Autocross with Motorsports Northeast. I came in 1st place and also set FTD. Click here.

08/03/07 Autocross with Motorsports Northeast. I came in 1st place. Click here.

9/7/07 Autocross with Motorsports Northeast. I came in 1st place. Click here.

9/28/07 Bought a new SLP shift knob. Bought new wheels for the track, SSR Competitions (Anthracite with a Polished Lip), from Tire Rack. 18x9.5, +50mm. Click here for pics.

10/8/07 Changed tranny fluid to Royal Purple Synchromesh but it made it harder to shift. Swapped in Amsoil ATF and it was better.

10/9/07 Pocono East HPDE and Time Trials, Katech Belt Tensioner. Click here for pics and vid

10/19/07 Autocross in rain with MSNE. Click here for pics.

11/27/07 New Coilovers (thanks Johann for the install), alignment (thanks David at Toyota) and corner weight results. Click here.

2/24/08 Installed 285/30/18 kumho v710's mounted up front on SSR comp 18x9.5 +50mm wheels. Click here.

3/4/08 - I won 2007 season class U in Motorsports Northeast. Photoshoot for Tri-state tuners. Click here.

3/30/2008 - AX with MSNE. First time with trailer. Pics (click here).

4/6/2008 - AX with MSNE. Pics (click here).

5/6/08 - Took the rear plastics out. Should I get a rollbar? Click here

7/12/2008 - AX with NNJR SCCA. XP class. Broke front end-link. Pics (Click here).

11/5/2008 - Installed rebuilt transmission, poly motor mount, oil pan baffle, new clutch, pressure plate and aluminum flywheel. Click here.

12/20/08 - Installed rollbar and racing seats. Click here.

3/1/09 - Sold the rx7. Sad but its going to a good home. Bill, new owner, looks like he will turn it into a pure race car. Click here to see my last set of pics.


June 2009 - See what the new owner has done to the car. Click here.

June 2010 - New owner getting some press from Goodyear. Click here.

Sponsored by Johann Performance Installations

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