Thanks so much Scott! It is a pretty incredible experience to have this much acceleration in a car that also stops and turns. I need to get it on a track and stretch it's legs.

 

Track is the key word there. Getting on these big power cars on the street…even for a brief rip…gets you up in the 100 mph range in a few seconds. Hopefully the cops were gentle to you today. I hate speeding tickets. Be safe sir!

 

It’s funny how most non-car people think 100 mph is fast 🙂

 

Congrats!!!! That's a bad mf'r you have there. That much power with just 234 cam and not enough exhaust is impressive 👍👍👍. Sorry you got a ticket, those ****** are extra sneaky these days.

 

The extra shift is definitely going to hurt the time but you will be able to see what it should do without it. Mid to low 6s should be easy.

 

Thanks man! I thought for sure the small cam, stock heads and 2.5" exhaust were going to hold me back. Truly I could find more reasons going into the dyno that it would only make 530-550whp despite on paper 570whp was the bench race goal. I was bench racing off my old 402" stroker that made 512/509 with less cubes, less cam duration and lift, stock ls3 heads, less compression, a stock rodmod ls3 intake etc. Using the same Hp/cube from the 402 the LS7 would make ~545whp. I'm still in disbelief at the results.

The build plan worked out perfectly though. I spec'ed the cam trying to match up with this intake and make peak power up high and rev out without a ton of overlap. I looked at a ton of LS7 builds, and looked at the cams that were producing the most high rpm powerbands. I picked some targeted IVC and EVO events, and then backed the overlap up until it was at a level I was comfortable for street driving. These low shock lobes from Comp are my new favorite now too. Managing to get HP peak at 7000rpm with such a small cam makes me just super happy. The MCSA and volume of stock LS7 ports tune perfectly for 7000 rpm power peak, and the intake runners are extremely short and very tapered promoting high velocity. You can see the back of the intake valve from the plenum lol. I was just very fortunate all these parts are working so well together, and my valvetrain can support the trips out to 7800rpm lol.

A low 6 would make me super happy for a car that wasn't built for it! You'd know way better than me.

Full results and dyno video are over in the dyno thread I made.

https://ls1tech.com/forums/dynamomet...94-fd-rx7.html

 

Inspired by Tusky's update, I figured I'd share too. I've been enjoying the car a bit. Finished up a project I started back in 2019/2020 for some killer brakes for this thing. I'm super proud of these, and will be working to try and offer them as a kit through my buddy's company Ronin Speedworks that sells all the swap parts for these cars. They're Cayman S brakes from a ~2017, the 718 generation. I did all the design and prototyping, and my buddy did some FEA for me and final design checks. I had brackets cut on Xometry. Lots of effort went into finding appropriate calipers and rotor sizes that would be matched to the car. This is working with a stock proportioning valve and slightly shifted the brake bias to the rear. Most brake upgrades, especially on the rx7, make it extremely too front biased.

We did one autocross event with it so far, and have another one coming up this Sunday. My dad and I did double duty on it and the car did great doing about ~24 runs combined. Everything feels super solid. It is a chore to try and keep the rear tires stuck with this much power, but it is still a good time. Hoping the next event has a little bit larger of a course.


I picked up a Davis TC3 non-learning traction control box off Marketplace. I've not had any luck getting it to work. I've had some fun testing it though lol. I've verified it is working...receiving signal and sending out timing retard to the Holley, but I can't make heads or tails of how it is behaving. I'm using my speedo signal from the transmission as the input, which is being run through the Bowler Transmissions converter box to turn the VR signal into a hall effect type signal so the Holley can read it. Works great as my speedo in the Holley, but maybe it is too noisy for the TC3? I have the option to switch the speed signal to an RPM signal and try again...see if I can get it to function at all. I have future plans to add MK60 ABS to this car which will have a quality wheel speed signal. I also have dreams of swapping the 2010 vintage Holley crap out for MaxxECU.

No new 60-130 times yet. I drive modestly now I get resolution on my speeding ticket at the end of the month that I got on the way home from my dyno appointment I've been hesitant to drive the car too much, but trying to remind myself to get it out more.

I'm very close to pulling the trigger on an H2D printer and an Einstar Vega combo to tackle some more aspirational projects that'll let me flex my engineering muscles a little bit. I want to design and print my own intake manifold with the ultimate goal being ITB's. I've also played around with learning how to design headers in solidworks and would love to take a stab at a set of 8-4-1's like the ones that have been taking over the Corvette world. Lastly, I have some parking brake calipers coming and it would be a hell of a lot easier to design brackets on the screen than with cardboard lol.

In that spirit, I jumped on a pre-order for a new hood design that has way more room for activities. It is modeled after the OG MazdaSpeed hood, but hides a bit of a cowl in the vent design.

 

Nice update. I have 2 Bambu A1s and a A1 mini. The H2D looks like a beast.

I have some parts left over from the build i did on my buddy's car. If you might be interested in them or know someone.

 

There are multiple Facebook RX7 groups for buying and selling parts. Forums are not the preferred spot anymore. If they're V8 swap specific, hit up the Norotors facebook group.

You'd be a good one to ask - have you ever had any alternator problems with high RPM? I still have the original DR44 alternator off the 2006 GTO on the car. I just let it charge in the fail mode which is supposed to be ~13.5V. It has been acting a little funny since I rebuilt the car, and it was on my short list to get a one wire alternator on it that will charge up in the 14's. During the LS7 install I put a 3" pulley on the DR44 alternator to try and keep the shaft speed down.

We autocrossed again yesterday and it was going fantastic until it wasn't. We each did 4 laps in practice in the morning, and during my dad's competition runs the alternator got super weak and drained my battery until the Antigravity isolated itself by opening the contactor. The car kept running by keeping a high idle to charge at 12.5V, but at actual idle the voltage collapsed down to 11.5V. Very very fortunate to have a smart battery in this thing.

I had to give up my last 4 competition runs which was a bummer, but I luckily keep my battery charger in the car which is only a little 110 watt trickle charger. Maximum charge rate is only 4A at 12 volts for the lithium. Slow charged it for a few hours and I was able to drive it the 15 minutes home. It kept the voltage over 13V even when idling on the way home, so I'm wondering if there was some kind of heat soak issue that made it stop putting out sufficient voltage?

I purchased a Powermaster alternator with a 3" pulley pre-installed and one wire regulator. Hoping this does the trick. Shaft speed will be 20,000 rpm at 8000, 18000rpm is the supposed limit.

 

I ran the stock C6z alternator to ~7800 rpms constantly. It wasn't until I overloaded the system with some high powered radiator fans that I experienced issues at higher rpm that resulted in voltage drop. After that, I switched to a JS alternator and haven't looked back. The first one I ran, I kept the ~2-2.5" pulley that came with it and spun it to ~8000rpms with no issues. My currrent one, I put on a 3" pulley and have gone upwards of 9600rpms and it's still working fine.

 

Appreciate it man. I just dissected my GTO alternator (I think it is the same as the C6z, DR44?) and found nothing wrong inside visibly at least, but wouldn't be surprised if it started getting tired. Very old now. I don't have PWM control on the voltage reg so it would charge low voltage to begin with, and then the heat soak and larger pulley on top of that. During AutoX we just keep the car running between runs and that engine bay gets HOT. Never had a volt meter on the car before to know what the charge voltage was doing outside of some datalogs. Now with the Holley dash the warning lights started going off and let us know it was in trouble lol. A 14.8V regulator is going to do wonders for keeping the battery up. The antigravity battery is 13.2V for a "12V". I'm sure needs more of a potential difference to charge sufficiently. I've got two fans, three fuel pumps and EWP too.

I've read the Corvettes can be spun pretty hard and be fine. Only thing I've really read about is that sometimes they stop charging when the revs get too high vs having any major problems like breaking them. Our LS drag car we went through 3 alternators from over reving it with the rotor expanding out and hitting the stator so I figured I ought to put a larger pulley on mine before pushing the rpm.

 

It was a blast until we had to park it lol

 

This thing is a beast! I made it out to Streets of Willow on Friday and the car kicked ***. It is ridiculously fast, and honestly very easy to drive. I'm very happy with the setup. I could not be happier with the engine. It is tractable and has torque everywhere, and it just keeps pulling harder.

Only minor issue is dealing with oil control problems. Really wish I could fit a dry sump in this thing. I keep pushing oil out the catch can the faster I drive it. I have more parts coming for another revision of my crank vent and catch can. I should have stopped sooner as I knew it was puking, but I was having too much fun lol. It finally pumped it into the intake and started majorly smoking out the exhaust.


Here is the latest engine bay after swapping to BTR valve covers (the baffles still aren't enough).



There were multiple photographers out there and they all shared their pics for free. So awesome.





The aftermath of my last session. A little rust prevention lol. The rag never stood a chance.

 

A few months ago I took it to Church Auto Test in LA area for a tune to help with slow speed driving, and he above and beyond fixed my biggest gripes. I had some minor stuff wrong in idle and low speed areas that I just didn't have the time or desire to fix myself anymore. He fixed it falling on it's face taking off from a stop, fixed a steady state misfire at cruise, and it has way more throttle response and part throttle torque without bucking. So much more enjoyable to drive now. The Holley short runner intake is a little tricky, but with the steady state dyno tuning he was able to find that it needs to run ~14.0:1 AFR due to distribution problems causing lean misfires.

I also was always suspect of my ~615whp dyno number from my buddy's roller dyno, so a nice byproduct of him fixing all my drivability issues is that I get to recheck my power figures. The 594whp number is way more believable for stock heads, 2.5 exhaust and a pretty small cam. It made me feel good that he didn't find anything at WOT power wise from the tune I did for the car.

Church's dyno is a hub dyno, and I had the car on it when it was a 402 with a mild cam. I did an overlay of the two engines and it is such a great visualization of my goals being realized. I wanted a sports car powerband, and I wanted to add horsepower without increasing torque too much as I was already at the reasonable limit of traction.



November 1st I'm doing the No Fly Zone 1/2 mile drags in Central CA. Not really sure what to expect speed wise, but I'm thinking probably in the 165 mph range. I have some NT555R2's 275/40/17's coming, and some super cheap 17 inch wheels. I didn't really want to spend the money, but my Advan tires spin through 3rd gear when they're cold and there's no tire warming area or burnouts allowed at this event. I am looking forward to hopefully getting a good 60-130 number even though I'll need two shifts to hit 130.

With the 25.7" tall Nittos it'll be geared like a C6Z with 3.90's and stock tires, or 4.10's and 28" tall tires.

 

Maybe after some 1/2 mile results I can sneak into the @Tuskyz28 cookbook

Although the engine combo is pretty simple

 

Good stuff, as always Spanks. Love the build and attention youve put into it.

 

Thanks Scott!

 

Impressive power for such a small cam. Those LS7s are beastmode for sure. Love simplicity of builds like this but very detailed and well thought out combos/parts selection goes to show its not all about a dollar. Car moves good and sounds good too. Enjoy your go-kart on wheels.

 

Thanks brother. I'm thrilled to get this much power from stock heads and stock compression except for a thinner head gasket. Hope to see some rips from your ride soon!

 

Well that was a successful outing! Not a new passion by any means, but it was for sure a fun time. I am way more looking forward to the next track day haha.

We started the day hitting some high 150's, and then I took a datalog and dug into the tune. My tuner left me a little soft on timing, especially with the E70 I had in it. I threw 4 more degrees at it and picked up a chunk of mph. My best two runs were 161.5 and 163.28.

Weather was about 80 degrees, 2350 feet of DA, and a ~6-8mph headwind estimated. The airstrip is at 424' of physical elevation.

60-130 was a little bit of a letdown for me to be honest. I ran a 7.1 when I first put the car together on a bumpy road with a turn in it, going uphill at 1200 feet of physical elevation while starting in 3rd gear. My best runs were a 6.97 and a 6.94, and my dad ran a 7.00 backing mine up. I really thought the car had more like a 6.5 in it with this much power.

Flip side to that argument, you can see in the video I basically spun all of 2nd gear even with the Nittos, so maybe 3rd gear start would've actually produced a better time - cut out one shift, and for sure no spin. If I were serious about the 1/2 mile stuff I'd have to bite the bullet and get a Mickey on the car. The ET Street R's seem a lot stickier from what I saw out there.

The run on video was my 163 mph run and I feel like I truly got everything out of the car that I could have that day including hitting 5th just right. Even though I wanted a little better number, I got close to my 165 expectation, and I felt I left nothing on the table which made me feel good.

A couple comparisons, a brand new ZO6 with CAI and an exhaust ran 153 mph.

A 605whp c6z with Mickeys and skinnies up front and some weight reduction also ran a 163mph run as his best pass.

I've been having a nagging feeling that the engine has lost some performance from when I first put it together. The last few runs of the day ran slower by ~3-4mph too for no apparent reason, so that isn't helping lol. We had to do a quick and dirty plug wire repair when the conductor pulled out of the wire, so maybe the repair started failing. I'll do a leakdown when I change the plug wires out, but I'll probably just keep thrashing it until it gives me a more obvious reason to be concerned. For now it is giving me everything I need to have a blast, and is standing up to some pure torture.