8 Second Street Car >10k. (79 Mazda Rx7, Turbo LS)

Very cool! For me there's just something uninteresting about LS swaps or rather chevy/ gm anything swaps. Especially in a rotary engine bay. IT's just kinda.. "It's been done"... Very awesome though! Gotta love turbo noises!!!!!!!!!!!!!!!!!!!!!!!!!

Love following along- I especially appreciate the budget tracking. Good reminder that even going cheap adds up quickly.

Final engine bay… ½ of an Exhaust evac kit ($40) I split the cost with a buddy.

Sold the 6” cowl hood to a local building a BBC RX-7 for $350. I wanted a stock flat hood for the sleeper effect.

Found a $25 stock hood (craigslist). Spent 2 days doing body work. Fit great! (more on hood later)

Random other goodies I forgot about.

Ebay Pneumatic mini regulator $4 (boost control)

Ebay exhaust wrap $35

Had to get creative with the headlights. Old owner glassed over the original headlights. Weather pack connectors/pins $25 Headlights (ebay fog lights) $16 a set. $32 total.

Head light bucket design.

Finished buckets.

Bumper body work

I ended up tinting these in the end.

Boring signal hi/lo beam video with tinted lenses. Came out pretty damn good I think!

https://www.youtube.com/watch?feature=player_embedded&v=-MaOCmUanOo

($25…if that) DIY 5” cold air induction with dryer flex joints. I’ve made many of these. They are very strong and light weight. You can also pop off the crinkle ends and add to them. Theres even a rolled bead like end for your couplers/filter. This put my filter under the head light area and out of the wheel well where I had it.

(This is a more recent picture with a new, better, IC I added. But it shows filter location.)

$2400 Remaining.

We all know there’s at least $1000 worth of misc BS I left out. (probably more) Materials, oil, sealants, hardware etc. Even with that I still think I made this car for roughly 10k or less.

When I was hanging my $25 hood to paint one of the S-hooks unbent while the paint was drying. Destroying a hood I easily had 12+ hours of work in. I was so ticked I bought a $600 “Bolt-on” carbon fiber hood. I don’t think that should count against the budget, but that’s the hood you see in this pic.

Also weighed the car at the local dump. 2950lbs with me in it. That means I'll need over 800 crank HP to hit the 8's.

It's ready for the track!

Oh yeah! I can't wait to see what it does at the track. I imagine there will be a ton of fine tuning once you get there.

First track visit!

Running pump e85 fuel. Drove to and from the track. Not much seat time so far just mild street tuning. The car is a beast. It will spin the 29X12 slicks from a 50mph roll at anything over 12lbs of boost.

First Pass

8.5 psi (as low as It would go, my “street” tune) it went 11.2 @ 125. Lazy 1.7 60 ft. Pig rich, 10* of timing. Cranked the boost knob a tad. Leaned it out 10%.

2nd pass. Popped a coupler off. It was impossible to get to without removing the bumper. No more passes that night, but I did cruise there and back without destroying anything.

2nd track visit. Getting better, but far from an 8 sec pass. Driven to and from the track without a hiccup. Also thought it was funny I averaged 18mpg….on e85 even! (3.10 gear 29” tire)

Made 7 passes with a best of 9.83 @ 143.

9.83 @ 143 @ 17lbs 10.8 AFR 15* of timing shifted at 5400rpm. Still a crap 60’ time (launch).

Put some tinit on the old girl. Her present for breaking into the single digits.

3rd track visit.

Best of 9.66 @ 144. Still can’t get the car to launch hard. Easily a half second ET there.

Few videos a buddy took. Crazy how quiet it is.

https://www.youtube.com/watch?feature=player_embedded&v=kLX_ABTQdCg

https://www.youtube.com/watch?feature=player_embedded&v=vnWkgvatp-8

Drag racing really isn't my thing, but I've got to say you're doing a great job of making this interesting.

I'm guessing that the next updates include modifications to suspension and/or tires to better get the power down.

Whats the reason for a 5400 rpm shift? It seems like you would keep making power well past 7k with that cam.

MrJoshua wrote: Whats the reason for a 5400 rpm shift? It seems like you would keep making power well past 7k with that cam.

This was my first attempt at an LS engine. I was a Turbo Buick guy previously (Grand Nationals). Which are notorious for tight clearances, low RPM, and big boost. To me, the LS engine looked the same in many ways. Rod bearing clearances are .0009-.0025 from the factory with a .003 service limit. And the crank bearing clearances are even tighter! So I treated it like a turbo Buick.

Also to keep this build budget friendly a 7k+ redline would require aftermarket valve train parts, intakes,aftermarket oil pumps etc. As the years went on though I did find out I was being overly cautious RPM wise. The factory intake manifolds are tapped out by 6000-6500. I shift from 6500-6800 these days.

4th and 5th & 6th Track Visits.

I stopped adding power and tried to sort out my suspension and ladder bars. Managed to do more harm than good mostly. But got it back under control by the 6th track visit. Managing a new best of 9.49 @ 147. Boost was at 18lbs by this point and would creep to 20lbs in high gear. Still short shifting at 5800 or so and timing is more aggressive at 16*. Still cruising to and from the track and street driving this pig. Pretty amazing for JY motor!

7th visit. Bumped boost to 20lbs creeps to 21. Boost controller is maxed. Need more spring in the WG to go higher.

9.44 @ 148.

8th Visit. Bumped timing up to 17*. But spent most of the night working on my suspension.

9.35 @ 147

I don't know too much about drag racing, but are your rear wheels beadlocked? The one time I went to a Top Fuel competition, I saw that the wheels they run are beadlocked. I didn't notice that on yours.

this thread is awesome. There are not enough high hp builds on this forum!

scardeal wrote: I don't know too much about drag racing, but are your rear wheels beadlocked? The one time I went to a Top Fuel competition, I saw that the wheels they run are beadlocked. I didn't notice that on yours.

No bead locks. For comparison the average Top fuel engine makes 5000-6000 hp. They generally run over 200mph in the 1/8th mile.

It’s really not necessary at my power levels. Many do drill holes in the rims and run self-tapping screws into the bead at power levels similar to mine. I’ve marked my tire and they don’t spin on the rim much. You can see them “wrinkle up” here.

In reply to scardeal:

He did it exactly right, common practice is to mark the combo and see how much it spins. My Dad's car was about a half rotation, so it got screws.

This build is sjper fun to watch. Dont drag race myself but do enjoy watching!

9th visit.

Tried a few new things. Used the 2-step launch control on the Mega squirt. This pulled timing down to -17 on the trans brake. Which resulted in lots of popping and banging along with lots of boost VERY quickly. Made 17lbs on the trans brake. This resulted in a new best 60’ of 1.38. Also shifted at 6300rpm and cranked the boost up to 23lbs, 15 of timing.

9.04 @ 151! Sooo close!

http://i.imgbox.com/abkKDJci.jpg

10th track visit. (Happens to be the last race of the year before winter)

5 botched passes (spun tires 100 ft out) Spoke with track manager. They swept and sprayed the track with traction compound for me.

6th pass.

Screw it… 24lbs launch on the t-brake. 24lbs of boost creeping to 25.8.

1.35 60’, 8.93 @ 153!

HP to weight calculator puts the engine right around 840crank HP.

Here’s that pass’s launch.

Slip

7th pass. Sitting on the trans brake at 3600rpm. At 14lbs the motor locks up. Not sure what’s wrong, it wasn’t very violent. Just quit.

Towed it home. Pull it apart that weekend and find this mess. Basically a total loss engine wise. It even took the cam out and damaged the heads. I believe the Autozone timing chain didn’t like the 2-step much and failed. No way to know for sure.

I’d also like to add this was a 2002 gen3 engine. Gen3 engines came with much smaller/weaker rods. I currently run the gen4 engines (2005 and up) with the stronger rods.

Gen3 VS Gen4 rods.

Still, that’s a year of abuse, 100+ passes, and a lot of street abuse on top. I feel like I got my money’s worth. Best part is you can cycle in another JY motor very cheaply. I’ve done this several times now. Best ET so far is an 8.88. Best trap speed of 159. I ran a 4.8 last year and still managed 9.0 @ 150 on 20lbs. (bigger turbo, better intercooler, LS6 intake)

No one believes me at our track when I tell them I run JY stock engines right down to the original bearings and hardware. Others have gone quite a bit faster than me in heavier chassis on the OEM long blocks. Cost VS performance, the LS engines are pretty amazing.

That's a great story. Good work on that two step, after watching one of the earlier videos, seeing you struggle with the boost on the line, I was wondering if you'd do the two step with super retarded timing at the line thing. Do you have any video of the 8 second passes?

ForceFed86 wrote: No one believes me at our track when I tell them I run JY stock engines right down to the original bearings and hardware. Others have gone quite a bit faster than me in heavier chassis on the OEM long blocks. Cost VS performance, the LS engines are pretty amazing.

I played with an engine on the dyno that was a LSX376 crate motor but we ran stock 4.8L crank and rods to make it a 339ci. With ported heads, an LS7 cam, Victor intake with port fuel injection and twin 80mm we made 1350+hp @ 8800rpm with 38psi of boost. And made dozens of pulls and never broke the rods or crank. These engines are ludicrous.

Glad to see it made it to the target! Shame the engine didnt wanna keep going.

Now I actually want to LSX all the things.

I was actually glad it was the engine that let loose and not something expensive like the trans/converter.

The videos I have are pretty random. Only get a few when I have a friend go with me or a fellow racer takes it. I have a few from over the years…

9.0 @ 154. Poor mustang!

https://youtu.be/LUsn9TllEqU

9.01 @ 155

https://youtu.be/epJGSI45zz0

Close grudge match race.

https://youtu.be/susJLKBzMNg

Has a forged rod/piston 370” LS motor in it now. Still factory untouched 317 heads. Mildish 224/224 @ 113 .610 lift cam. Installed a better intercooler and a billet 76mm turbo (1.254 T4). LS6 intake manifold, 160lb injectors. I finished out the cage beefed up the brakes, and added a chute. Last outing was 8.88 ET at 19lbs creeping to 20. I also remade the hotside using 2” piping to each side of the turbo scroll. This cut the spool-up time in half, and made the car really violent when boost comes in.

This is how the car sits now. I couldn't find a "race wheel" that fit over the FC turbo II brakes. So I ended up using the Spare Rx-7 wheels and painting them black.

New 2” hot side.

I noticed you have stopped keeping track of the budget at this point.

I have. It's not as bad as you'd think, but not GRM worthy. Safety equipment more than anything killed the budget.

Cool build, what kind of tire are you running on your spares up front?

Awesome! Definitely my favorite build on this forum. I'm a drag racing guy too. Very inspiring.

chiodos wrote: Cool build, what kind of tire are you running on your spares up front?

185/55/16" V rated deal. (24" tall) I think they have a z now too...

http://www.tirerack.com/tires/tires.jsp?tireMake=Kumho&tireModel=Ecsta+PA31&partnum=855VR6PA31&vehicleSearch=false&fromCompare1=yes

TheV8Kid wrote: Awesome! Definitely my favorite build on this forum. I'm a drag racing guy too. Very inspiring.

Thanks!