MmSadda's Non-Turbo (read: Supercharged) RX7 build

[MmSadda]

I suppose I should start this off with a little backstory. I first picked up this car in Fall '06, for $950; I'd taken it to a small local mechanic and gotten a good compression test, but the car would buck like crazy below about 2500 rpm, and I figured it had some major fuel pressure issues at least. Here's what she looked like when I got her:

[MmSadda]

Well, after getting the car to a Mazda dealership, and to Ken Carswell of Rotary Connection here in central Ohio, I found out the engine had shot an apex seal, in addition to needing an entirely new fuel system. I was disheartened, and thought about scrapping or selling the car. After a lot of deliberation, though, I ended up having Rotary Connection build a new, bone stock engine for me. I was completely broke at that point, so the car was spray painted in the interest of getting it to look a bit less junky.

[MmSadda]

Well, by late '07, I'd saved up more funds to dump into the car, so she got some S5 tails, a proper coat of paint, and some decent if inexpensive wheels and tires. I also picked up a few little accessories, like a Racing Beat strut tower brace, and a cone air filter.
The car saw a few pulls on the drag strip, and ran mid-17s at best. (FYI, I don't particularly care about drag times, but at least it's something of a measuring stick of straight-line performance, for a car that's not built for that.)

[MmSadda]

Well, around Summer '08, someone right turned on red right into the front passenger-side fender of the car. The car went back to the same body shop that did the first paint job. After completing the body work, they realized they couldn't match to the paint they had put on just a year ago. As a result, I ended up with a new (slightly darker and less brown) paint job, which I was REALLY pleased with I'd been toying with the idea of throwing on a spoiler, and had picked up a stock one and a Supra-style one (which I could never identify the brand of,) and with the car getting painted again, it was a perfect time to have a spoiler painted.

[MmSadda]

Over the course of late '08, up 'til about '10, the car experienced intermittent severe driveability issues, because of piss-poor wiring to the O2 sensor and TPS, and possibly a bad ECU. I also dealt with some 3800rpm hesitation issues, though those were much less bothersome. At that point, though, I was considering selling/trading the car in the interest of getting a TurboII, MkIII Supra Turbo, or possibly even a Starion/Conquest or Mustang SVO. Basically, I had given up on making this the car I wanted it to be.

Early this year, though, I started getting the idea of a turbo swap, or a supercharger, back in my head. I'd actually convinced myself that I wanted to swap to a turbo engine and sell off this one, but figured I'd give it one last ditch effort to find a reasonably-priced supercharger; this had popped up for sale less than a week before: (and yes, that's a Paxton/Nelson SN-89 supercharger kit, including the optional goodies such as oil cooler and blow off valve, with all of 20k miles on it.)

[MmSadda]

Well, I'd initially planned to run a SAFC-2, and do a pretty cheap build. I contacted Ken Carswell for his recommendations, and he referred me to his son, Logan, who runs Defined Autoworks. Logan strongly suggested using a Haltech ECU, and over the course of a few conversations with him and some other rotary-knowledgeable people (Glenn Price of Illicit Performance, out in California; Brian T / TitaniumTT of varoius rotary forums,) I'd concluded I needed to upgrade my fuel system substantially, and get at least a boost gauge and wideband in the car, to run safely. Having planned out all of the supporting mods (which ended up making things MUCH more expensive than originally planned,) I began the s/c install, which took all of two evenings with the help of a few friends.

Engine bay before pic:


All the supercharger kit parts on the garage floor:


A lot of stuff removed from the engine bay:


Me and my buddy with the supercharger:


After:

[dabranco]

I see a corvair in the garage..... Car looks nice man

[MmSadda]

I initially picked the car up with a street tune the day before Thanksgiving.

Here's a pic of the engine bay from then

[MmSadda]

So, here's where I stand now:

My car went to the dyno this past Monday for tuning by Logan Carswell of Defined Autoworks. It was supposed to be tuned to 8 lbs of boost. I was told to expect around 220-230whp.

I got a call from Logan shortly before I was supposed to pick the car up, saying that the tune went really well, but the car was only making 4 lbs of boost, instead of the 8 it was supposed to.

After some drama, he agreed to give me a discount on a re-tune. I since discovered that I had some oddball 5" pulley on the thing, instead of the 3.75" pulley that's required to run 8 lbs of boost. With that, I made 175hp, well short of the expected 220. Since then, I was able to contact Craig Conley of Paradise Wheels (the company that supports the supercharger) and was able to score the last one of the original 3.75" pulley that he had in stock! I've now got that in hand, and will be ready to slap that on in a couple days.... before that, though, Logan and I need to sort out an issue with AFT (which is used to lubricate the supercharger) escaping/spraying out into the engine bay.



I'll end this post on the most positive note I have on the project so far: After picking up the car on Monday, and having to wait for two days for a dry enough day to take the car out, I managed to barely avoid getting pulled over my first time hitting boost getting on the freeway. I also managed to get in a few drives with my housemate (with him in his STi.) Even at 4 lbs, the car feels good. At 8 lbs, it should be a whole lot better. I should know for sure this Wednesday

[MmSadda]

Originally Posted by dabranco

I see a corvair in the garage..... Car looks nice man

Good eye! That pic is from back when I was at my parents' place. The 64 Corvair Monza convertible is my dad's project car.

[MazdaMike]

Looks awesome dude, total sleeper. Ill keep watching this build!

[MmSadda]

Originally Posted by MazdaMike

Looks awesome dude, total sleeper. Ill keep watching this build!

Thanks, man! I do love the fact that it looks like a stock-ish car with a nice paintjob and a stupid wing. I kind of enjoy that I have the dumb ricer/mostly unmodified car look going on.

With luck I will have a proper dyno tune on Wednesday.

[MmSadda]

After the initial tune:
178hp, 4 lbs of boost.

[MmSadda]

Well, this has been way too long coming

[Duffman692002]

Was wondering about where this thing was the other day. 213 eh, Will that be all she does or wdoes Logan think he can get ya closer to the high end of his estimate? Looking good though, bringing it to DGRR?