1992 Miata, LS1, then LS3 swapped

[mazpower]

Oh and here's the first run, compared to the best run. The bulk of the power increase was from bringing the WOT ignition timing from 21.5 to 26.

[mazpower]

Its been a little while since I updated this. I've got a LSD now, along with Tein Flex coilovers, oil cooler, and NT-01s in 225 on the rear. No more wheelspin in 2nd!

Anyways got more goodies for the Miata. Now I can stop, thanks to my friend Miguel at Wilwood!

Wilwood 4-piston "big brake" kit for the Miata. Using the "E" pads and standard rotors.

These definately are not enough for a V8 Miata.


MUCH larger.


Caliper mounted up.


Back shot of caliper to show mounting. Yeah my balljoints are kinda sad, balljoints & bushings are next on my list.

You have to shim the calipers to get them centered on the rotor for equal pad wear. I only had to use one of the shims per bolt, where the caliper bolts to the supplied bracket.


The only real issue I ran into was that the Rotas I run wouldn't clear the caliper. So I used a set of 5mm spacers on the front, problem solved.


The car stops AWESOME now. It doesn't take much to lock up the front with the little 615k's, with the NT-01s it should be perfect.

[mazpower]

Took it to Chuckwalla Raceway in Desert Center, CA. Managed to outrun a ZR1 on the straights. That's the Vette that I pass and he tries to keep up. Ran flawless other than some oil smoke as the temps came up, might be the rocker bolts not sealing correctly.

Both videos are the same timeframe, one is front view, one is back.

[mazpower]

I haven't updated this thread in a while, all sorts of new stuff for the Miata.

I got a hardtop for cheap. Painted it satin black and called it good.


Then I had a mini catastrophe. I let a good friend drive the car, who had driven it several times in the past, and during a hard 2nd to 3rd shift the passenger side diff mount stud ripped right out of the subframe.













I had the diff repaired and picked up another subframe and reinforced it.









Then I finally got to get started on the set of Z06 243 heads I'd been sitting on for a while. I cleaned up the ports a bit and had them flowed on a bench. At .550 lift, the ported heads flowed 286 cfm on the intake side, stock is 275 cfm. Exhaust was in the low 200s. In comparison, the 853 heads that were on the car before flowed 247 cfm. That's an increase of 39 cfm on the intake side and the mid lift flow is much higher in comparison as well. With the increased port volume - 210 cc versus 200 cc on the old heads - these heads are definately an improvement.





I had a full valve job done on the heads and took .015" off to maintain compression near 11.4:1 static. Since the heads were coming off, I decided to go with LS7 lifters. This helped tremendously with the "sewing machine" noise this engine has had since the beginning. Lifter preload was in the .040"s before, now its at .090".

Bores are still in great shape, pistons look new after 12k miles of HARD driving.



But then disaster struck. Trying to bolt down the new heads I pulled head bolt threads on both banks.



I picked up a Time-sert kit to repair the holes and get the engine back together with ARP head bolts.



With the new heads I have definately picked up horsepower but the bottom end torque is a little weaker now. As I haven't taken it to a dyno yet, the only measurement I could make was a freeway run with my friend's supercharged C5 Z06 making 636 rear wheel HP. We ran 50 - 150 and before the heads I would hang for about 3 seconds and he would pull by about 5 cars. Now with these heads I pull on him until I get into 5th, and he barely starts pulling away, to about 2 cars at 150.

[mazpower]

Updates! Lots has happened since I've been here last. Some good, some bad.

First let me give a HUGE thanks to my friend Brian at Indio Motor and Machine for helping me out with my latest build!

Last engine went boom at a local track day. 5th lap into the run, on a brief straight in between turns, loud boom at 6k RPM in 3rd gear, WOT, engine shuts down followed by an insane vibration until I press the clutch in. I pull off the track and check the car out once the tow truck comes out...no leaks, nothing looks broken. Once I'm in the pits, I find that one of the Haltech fuses are blown and the ECU isn't coming on. I fix that, crank the engine and see that the Haltech isn't reading RPMs...there's something wrong with the crank position sensor. This, along with the bad vibration, leads me to think something bad happened in the engine.

I get it back to my shop, pull the oil pan, and find this.



That's the big end of #7, still on the crank. It spun freely so it wasn't an oiling issue that broke it. I pulled the engine and stripped it down.



Fresh marks on the piston are from it hitting the head as the rod snapped.









Crank journals on #7 and #8 were in excellent condition.



The block and camshaft were trash. What ended up happening on the track was once the rod let go, schrapnel from the break hit the crankshaft position sensor and destroyed it, which blew the fuse for the Haltech and shut the engine down. This saved me more catastrophic damage like a hole in the block which most certainly would have led to an engine bay fire.



After consulting with my machinist and Scat - the manufacturer of the I-Beam rods and 4340 crank I'm running - it was determined that quench (the distance between the piston and head at TDC) was too tight and that an overrevving condition allowed piston to head contact, which in turn fatigued the rods until they broke. There were almost a dozen times where I mechanically overrevved the engine, trying to shift from 3rd to 4th and ended up in 2nd...thanks T56 shit shifter...anyways the datalogs in the ECU showed that I never went over 8500 but revving up there was obviously too much for the rods. The next engine needed to be better.

With the engine trashed, I needed a new setup. All that was salvagable was the crank, heads, and main studs. So I opted for a brand new LS3 block from GM using my Scat 4" crank, which gave a displacement of 415 cubic inches, or 6.8 liters, with 4.065" Mahle pistons, K1 H-Beam stroker rods, and a Texas Speed & Performance "Magic Stick 3" cam. MS3 is 237/242 duration int/exh at .050", .604/.609 int/exh lift, and 111 LSA. I needed new valves for the head as the #7 piston had hit the valves but not bent them, we didn't want to take any chances. LS6 valves are no longer available so I ended up with Ferrea SS valves. The heads were reworked for more flow at .300 to .550, picking up 20 cfm at .300 and .400 and flowing 295 cfm at .550. Another 15 FPS of flow were picked up across the board. We ended up with 11.7:1 compression when everything was said and done. A little high but nothing a tune can't adjust for.

Mahle pistons


Assembling the short block








Keyed SLP harmonic balancer with a ARP balancer bolt. This way I don't have to stress out setting trigger angle in the Haltech, as stock LS stuff doesn't have timing marks.


Shiny combustion chambers


A whole bunch of aluminum


And back in the car. Took 2 1/2 days of work to get running.


Finally with the car running again, I could install the AIM MXL Strada dash I had been sitting on since shortly after the engine died in February. First I needed to get the Haltech reading the vehicle speed sensor on the T56. I thought this was going to be an easy task, but no, nothing with this car is.

The VSS on the T56 is a reluctor. This means that it works like the trigger sensor on a RX-7, where you have a metal ring with teeth and a reluctor sensor...as the teeth pass the reluctor, the reluctor generates a sine wave which can be interpreted by the ECU as a trigger event. The Haltech only accepts a 5 volt square wave signal for speed...same goes for the speed input on the AIM MXL. They won't work with a sine wave. So I searched for a solution. There are converter boxes which transform the signal and even massage it to compensate for changes in tire diameter. They are $150 and above. Then there are reluctor adapters sold by Haltech and other companies that take a reluctor signal and convert it to a square wave. They are $200 and above. Lastly I could go the "fancy" route and have a trigger wheel machined to sit on one of my wheel hubs and use a hall-effect sensor, which natively creates a 5v square wave, to read speed. That would be $200-$300 and would be a lot of work.

For a while I've had a theory that a GM HEI ignition module could be used as a cheap reluctor adapter, but I never had an opportunity to try it until now. The HEI ignition module sits in the distributor of the car it came from, and processes the reluctor signal into a square wave for the ECU...it also controls timing and fires a coil but I wouldn't need all that. I went down to Auto Zone and bought a 7-pin ignition module for a whopping $27...it was for a '84 Chevy Camaro with the High Performance 305. I wired up the reluctor wires from the VSS to the inputs on the sensor, taking care to match polarity, and ran the tach output to a Timed Input wire for the Haltech, and hooked up power to the sensor. Grounding is done via the mounting holes for the sensor.

Basic wiring layout


I then got a usable signal in the Haltech and got an accurate speed reading, after messing around with the pulses per km value in the Haltech. I made an aluminum backing plate for the ignition module and put the thermal paste on it (the sensors tend to burn up if you're not careful, in a "stock" setting...I'm not running a coil off of it so it should run cooler but better safe then sorry) and bolted the whole thing down near the Haltech. Then I discovered a nagging issue with the E11v2 where it would read 400 km/h until you moved for the first time. This would really screw with my trip and main odometers, which was the reason for the MXL in the first place, so I ended up wiring the module to the MXL directly and everything works perfectly.

And damn do I love the MXL...one of the best investments for the car so far. It connects to the Haltech via the CAN bus and shows all of the sensors that the Haltech sees. You can configure 6 sensors to view in the MXL, 2 of which are displayed all the time while the other 4 are paired up and can quickly be toggled by pressing a button on the unit. It also has 6 warning lights that can be assigned to any sensor, customizable shift lights, current gear, rpm, and speed.

I gutted the stock gauges, leaving only the fuel gauge, and used a piece of aluminum to mount the MXL to. I screwed up on the hole for the fuel gauge and had to drill two so the whole gauge was visible. Version 2 of the cluster will be done in painted lexan with the "hole" over the fuel gauge left unpainted, along with a plastic ring placed between the gauge and lexan for a "stock" appearance. I'll also set up turn signal, high beam and warning lights.

[mazpower]

The build was done 3 weeks ago, the engine is broken in and street tuned. Still need to get it to the dyno for fine tuning and to set up a race gas-only map. The car is much faster than before. Here's a shitty cell phone video I made driving the car the other night.

[My5ABaby]

Makes me feel like my rotary is super reliable.

Nice build though. I'm sure that thing is ridiculously fast...

[RotorDad]

Nice project man, thanks for posting it.

[mazpower]

Originally Posted by My5ABaby

Makes me feel like my rotary is super reliable.

Nice build though. I'm sure that thing is ridiculously fast...

Yeah I've been reminded that I could have built a really nice 20B with what I've spent on these 2 engines. The LSx engines are the same as any other performance engine and when they break, they break bad.

Thanks! I haven't dyno'd it with the stroked LS3 but I'd guess its in the 450s. Its dead even with my friend's boosted C5 Z06 that makes 703 at the wheels. I've pulled a lot of timing because of the comp ratio to be safe. It'll get turned back up on the dyno. I'm hoping for 500 on race gas with the shitty headers I've got.

Originally Posted by RotorDad

Nice project man, thanks for posting it.

Thanks for checking it out!

[My5ABaby]

Originally Posted by mazpower

Thanks! I haven't dyno'd it with the stroked LS3 but I'd guess its in the 450s. Its dead even with my friend's boosted C5 Z06 that makes 703 at the wheels. I've pulled a lot of timing because of the comp ratio to be safe. It'll get turned back up on the dyno. I'm hoping for 500 on race gas with the shitty headers I've got.

That's why I love tuned cars. Straight line, his $90,000 Z06 is comparable to the $20,000 (or whatever) build and it's not like Z06s are even that nice inside. Turns, I'll take a Miata any day. 3200lbs vs. 2500lbs...

[RX7 RAGE]

That's a nice LSX project you got here Glenn.

[FC3S Murray]

Nice build man! I cant imagine how fast a miata feels with a LSx. My FC with a cammed 2004 LS1 made 425rwhp & 417 rwtrq(corrected) and it is a fucking rocket.

So did you ever figure out what causd your #7 rod failure on your 2nd motor? Those were aftermarket rods and pistons with that stroker kit right?

[mazpower]

Originally Posted by FC3S Murray

Nice build man! I cant imagine how fast a miata feels with a LSx. My FC with a cammed 2004 LS1 made 425rwhp & 417 rwtrq(corrected) and it is a fucking rocket.

So did you ever figure out what causd your #7 rod failure on your 2nd motor? Those were aftermarket rods and pistons with that stroker kit right?

Basically it ended up that quench was too tight, and there were a few times where I was in the top of 3rd and ended up in 2nd instead of 4th...from what I could tell I never went higher than 7K but who knows. I did this quite a few times trying to get the shifter figured out. When it let go, it had been months since it happened. It's the only explanation my machinist could come up with. Rods were Scat I-Beams and pistons were Mahle. I'm running K1 H-Beams and Mahles in the latest build.

[FC3S Murray]

Originally Posted by mazpower

Basically it ended up that quench was too tight, and there were a few times where I was in the top of 3rd and ended up in 2nd instead of 4th...from what I could tell I never went higher than 7K but who knows. I did this quite a few times trying to get the shifter figured out.

Aghhhh yes, I have read that mis-shifts are the #1 death of LSx's besides the dreaded oil starvation from the stock F-body pan on track event days.
You are lucky you got away with it a couple of times.

I feel you on the shifter....the damn shift gates on the T-56 are DAMN close....too close for comfort if you are required to shift/downshift with urgency and percision

You ever install an accusump or did you mod the pan?

Anyway, good job man...I wish I was near you. I would love a ride in that thing.

[mazpower]

Originally Posted by FC3S Murray

Aghhhh yes, I have read that mis-shifts are the #1 death of LSx's besides the dreaded oil starvation from the stock F-body pan on track event days.
You are lucky you got away with it a couple of times.

I feel you on the shifter....the damn shift gates on the T-56 are DAMN close....too close for comfort if you are required to shift/downshift with urgency and percision

You ever install an accusump or did you mod the pan?

Anyway, good job man...I wish I was near you. I would love a ride in that thing.

I never went with a Accusump and I'm running a modified F-Body pan. Just kept it overfilled a tad. My crappy welding and the high zinc content of the stock pan finally bit me in the ass, the pan started leaking bad after the recent build. I grinded down the beads and put some JB Weld on the pan to try to fix the slight seepage I was getting before. So I ordered up a custom pan from V8 Roadsters that has trap doors for the pickup so there's no starvation...also its 7 quarts, it uses a remote filter. Its gonna be here Tuesday, I'll post some picture up.