I guess itís time I start a build thread. Iíve had my í99 apart for a year now. I tore it apart last year and swapped the entire drivetrain, built a new engine myself, 6 speed, and an EFR 7670, RX7 LSD. That turbo was too big/my setup sucked, took it apart last September. So then I thought it would be a good idea to compound it with an FFS SC That too was a bad idea, and Iíve scrapped that mess all together. Then it just sat.
So for the last few months itís been sitting in the garage as I tried to figure out what I really wanted out of the car. To be honest I drove a new Mercedes C63 AMG and it got me thinking about what I really wanted out of the miata as the C63 is fast and has lots of torque everywhere, yet itís completely stock, passes emissions, and is civilized/nice/reliable at the same time. If Iím going to build my miata up it, should at least be faster than this thing considering itís a 4 door luxury boat thatís stock. Hereís what I come up with for my goals:
- I can drive it anywhere, and beat on it, and it wonít break, wonít overheat, wonít starve for oil, etc. I want it overbuilt, no shortcuts taken. So this means sleeper is out the window as that involves compromises that will affect reliability and performance. Iíve been spending a lot of time in the race prep section learning what everyone does to make these cars reliable on a track, but I got a lot more to learn. So if you see something Iím doing wrong please let me know! I want this car to be track-worthy.
Safety System to Monitor for Problems
- I want a system in place that monitors all the things a typical race car would have a gauge for, and then some, and then some more. I want to be able to establish a ďsafeĒ range for each variable, and have it alert me if one of them goes out of range. This system will be a Go/No Go gauge so to speak, as it will tell me if everythingís ok or if something is overheating, or low on pressure, or not-normal. I also want to be able to datalog all of this so I can improve the Safety System as well as the systems on the car as I identify the weak links. The system will have LED monitors and an audible alarm for critical failures. It will be either Arduino based and communicate via CAN to other devices.
- From an operations side, I want it to be DD friendly. So runs on 93 pump gas, has street tires (whatever the stickiest there is, I believe Iíll run 15x9 6ULs and 225 NT01ís), has a knock detection system that works, doesnít sit so low that I canít drive it on the street, has A/C and P/S and a stereo. I donít care if it rides rough, is loud, vibrates, etc. But I want this to be a legitimately streetable car, no race fuel, no slicksÖ
Instant Response, Torque Everywhere
- I want a torque line. If I was building a track-only car it would be turbocharged for sure or a V8 swap. But I want a car that has torque everywhere with no lag. In all honesty I should probably be putting a V8 in the car but too late for that nowÖ. I decided to keep the BP engine so a supercharger setup is the best way for me to get a nice flat torque curve with instant response, no lag, no hesitation.
Pass TX Emissions
- I live in Houston so I need the car to be able to pass emissions testing here. They do an OBD2 port scan here and then a 25-0 brake test to make sure the car can stop within a certain distance. Brake test is no big deal to pass in a miata, but the only way itís going to pass emissions testing here is if the factory ECU is in place and all the emissions equipment is either working, or the ECU thinks it is working. They check for codes and readiness monitors. More info here (TxDPS - FAQs: OBDII Emissions Testing
) Iím ok with removing/disabling some of the stuff if needed once it passes, but would prefer to leave it all working of possible. Iím hoping just swap in a catalytic converter for emissions day if running it all the time doesnít work well.
- Of course it has to be fast too. I want to make at least 350whp, and the setup have headroom to make a bit more down the road. Iím not trying to build the fastest miata in the world, just what I consider to be fun to drive. Yes I will dyno it, and post results when my old username is given back to me.
- Once itís running well and Iím happy with it, Iím going to buy a new bumper/headlights/taillights, and get the car painted. Itís a Ď99 and it needs a paint job to look nice again.
So based on those goals, hereís what Iíve come up with:
I found a machinist in Houston that builds performance engines and he seems to have a great reputation and has built a lot of miata engines. He has a deck plate for the BPÖ. I brought him the following parts to put me a shortblock together:
03í Block and crank, 48K miles on them.
FM Weisco Pistons, 84mm
Carrillo H-Beam rods
ACL Race bearings/OEM Thrust bearing
ARP Main studs
ATI Harmonic Damper w/ SC Pulley
He has the bottom end ready for me to pickup, he cleaned/magnafluxed the block, bored and honed it using a deck plate to 0.0031Ē clearance IIRC (Iíll have to ask), he line bored/honed the main caps with the studs torqued in, balanced the entire assembly, polished the crank, fitted the rods to the pistons, gapped the rings for 30 PSI Boost, delete oil squirters, . He may have done a few more things, he was talking fast and thatís all I wrote down. Iím going to talk to him more when I pick it up.
I built the VVT head last year so Iím going to reuse it on this bottom end. It has:
Fancy Supertech valvetrain, intake valves, +1 Inconel exhaust valves, titanium retainers, dual valve springs, 5 angle on the intakes, 4 on the exhaust, surfaced flat to <10 RA surface roughness, ported, deshrouded, bowls blended to seat/combustion chamber, polished combustion chamber. I did all the head work, just bought a Newway seat cutting system and built a valve grinding machine for tipping the valves to adjust them. Itís revved to 8700-8800 and not broken, so at least this part of my old engine did ok! Note: donít rev a boosted BP to 8800 with rods-only bottom end and expect it to lastÖ. Or probably any BP engineÖ
I found CodingPardoxís dyno and looked at his setup and decided I liked it enough that if I only wanted 350whp, that looked like a pretty sweet way to get it. After talking with him and doing more research, I found the W100AX, which is basically the same blower he uses, but a more efficient version thatís rated up to 20K RPM instead of 13K, and itís rated up to 30 PSI Boost. Did some math and it looks like this blower will move about 56lb/min at 8K RPM at 2:1 pulley ratio which should be ~30PSI boost, 60lb/min at 8.5K. So this is enough air for my power goals.
I looked at mounting it hotside or coldside, and decided hotside would be best since that makes intercooling it easier. Also I can use the stock intake manifold too and most of the emissions equipment will be plug and play on it. Iím going to reinstall my old 20x12x3 core bar/plate intercooler so should have good charge cooling. I may even order a new A/C condenser/lines and move the intercooler up front. But then Iíd have to vac and charge the system again and itís been working fine for years with my custom A/C lines so I hate to open itÖ But weíll see.
Iím going to use a 6 rib belt setup for now. The gentleman at Whipple swears it will work at 30 PSI with no belt slip on a 6 rib. Weíll see. If it slips Iíll change it of course. Due to packaging constraints there will be no autotensioner, will have to manually tension the belt like the others on a miata.
The setup will clear factory A/C, P/S, Factory header, factory HEAT SHIELD (with small modification to heat shield for 2 SC mounting tabs), clear the hood by minimum ľĒ, master cylinder, and lower radiator hose inlet. The bracket weights 9.4lbs currently, pretty sure I could lose another pound if I tried, but wanted it overbuilt so it never cracks, or vibrates, etc.
I plan to weld/port the factory header to get it flowing a bit better, cut the collector and weld a 3Ē pipe to it, and wrap all of it with fiberglass header wrap before reinstalling the heatshield. All to try and minimize heat soak of course. I have not done this yet. And 3Ē exhaust of course.
I have a 03í engine, I plan to remove the reroute and run the stock 03í headgasket with OEM location water neck/thermostat. Also plan to do a bypass thermostat for the heater core, gotta work out the details on this still.
I have a new MSM Radiator.
I have new modified SPAL Extreme Performance 12Ē Fans mounted on a modified FM Fan shroud. These are the strongest 12Ē fans SPAL makesÖ. They pull 40 Amps EACH. They move a bit more air than the OEM Fans do when wired in series getting about 6.5V... In parallel itís fairly impressive how much air they move, itís enough ďthrustĒ that it can lift its ~8lb weight up no problem. I built a series/parallel controller so I can run the fans on LOW (series, 6V each/12V total and only pulls 20 Amps, 240W) all the time when the engine is running to keep air moving through my intercooler/engine bay, and then switch them to HIGH (parallel, 12V each, 40A each, 80A total, 960W) when needed. Iím planning to wire them so they automatically go to high if throttle > say 50%. It also has a time delay relay installed so fans run on low for 2 minutes after key off to cool down the engine bay/intercooler a bit to reduce heatsoak.
I suspect this cooling approach will be adequate for the street and probably fine for a drag strip, but I donít know (I doubt) it will work for a racetrack. So Iím open for ideas here. I do have my factory under tray and decent front end ducting. My thoughts are either a better radiator, or another radiator located somewhere else. I also considered moving the a/c condenser somewhere else, Iíve seen this done on Porscheís before so the radiator/intercooler gets good air.
I have a FM oil filter relocation kit, a Large MOCAL Laminar flow oil/water oil cooler, and a 2qt Accusump all going on the car. I have a diagram Iíll try and scan in later, but basically oil will go out of engine to the remote filter, then to the oil cooler, then back down to the block. Right before it gets to the block, Iím going to Tee in my Accusump there. Oil filter will be somewhere near the firewall area, oil cooler up front somewhere in the upper radiator hose (so it acts as a oil warmer/cooler) and the Accusump will be somewhere at the bottom of the engine bay.
Will convert to return-style fuel system. Iíll try to scan in my diagram as well, but basic setup will be:
Tank, Walbro 255HP, factory line to front, factory to 6 AN adapter, 6AN to Regulator, Regulator to Fuel í03 fuel rail. Return line will be 6AN and go to rear, few fittings, and back into the tank. Obviously will be deleting the factory regulator in the rear. I think a 255HP is enough fuel pump for 350whp on gasoline, but not 100% sure.
MS3 PRO/Factory ECU
Iím planning to install a new (used) factory 99í ecu and harness, and then modify it so that the stock ecu is plugged into everything it normally would have, EXCEPT the ignition coils and fuel injectors. Cam, Crank, TPS signals will be sent to MS3 PRO. MS3 PRO will have all the usual sensors. This way stock ECU THINKS itís running the car, and it will be running all the emissions equipment, alternator, idle, a/c comp, a/c idle up. MS3 PRO will actually be running the car regarding fuel and spark. MS3 PRO will also have an idle valve or a solenoid, something so I can idle-up when my fans come on since they pull 80A on high incase they ever go high at idle. I am also going to install a GM MAF sensor pre-SC so I can datalog airflow. This is surprisingly easy to do, and will allow me to make changes to the setup and see how they affect airflow through the engine (like with/without cat, with/without muffler, different pulley ratio, anything really) I may try MAF based fueling down the road, but no promises since MAP based works fine.
This isnít finished yet, more or less still ideas and some diagrams. I have the Arduino, ordered a CAN-EGT as well as a Reverant 24CH Analong to Digital to CAN box, so Iíll be able to record a lot of data. Right now the plan is to have 8 K-Type thermcopules through the CAN-EGT for:
Charge Air Temp_Pre-Intercooler (post SC)
Charge Air Temp Post-Intercooler
Engine Coolant Temp_Pre-Radiator
Engine Coolant Temp_Post-Radiator
With this, I can directly measure heat exchanger effectiveness for both the intercooler and radiator. I plan to test out 2 different intercoolers and possibly several different radiators and with/without fans so I can prove/disprove what works to optimize the cooling for my car. Yeah for data!
Also will Reverantís 24CH box (only 16CH available since CAN-EGT uses up 8) so Iíll have these GM temp sensors:
Oil Temp, Trans Temp, Diff temp
And Fuel pressure, Oil pressure, Coolant pressure
IF I ever put water injection on the car, Iíll datalog flow, and WI pressure. Thatís something I plan to Add IF I find out I need it. Iíd rather keep it simple and not use it if possible but weíll see.
I may add an exhaust backpressure sensor, thatís a maybe.