Just your average K24/Drysump/Stocksubframe/S2000trans build for NASA/WRL
#1
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Just your average K24/Drysump/Stocksubframe/S2000trans build for NASA/WRL
Edit: Honda stuff starts at post 65.
After 10 years of mostly lurking on this forum, I've finally decided to make a build thread. I've learned a ton from this place over the years but haven't had many opportunities to give back, so I'm going to attempt to document my Ecotec swap. Most of the good ecotec information is buried in facebook right now, and... ****. That.
I'll be running this car in WRL GP1 and NASA ST4, and maybe ST5 as well with a detune and a bunch of ballast. Honestly the ecotec swap still ranks pretty low on my list of favorite miata engines, but I decided it's the best fit for my needs. The endurance racing aspect meant ruling out boost, both for reliability and fuel economy reasons. The NASA ST4/5 rules mean I have to keep the stock unmodified subframe, so Ecotec or built n/a BP were really the only two options left. A lightly built BP can make enough power for ST5, but the Ecotec makes 20-40hp more for quite a bit less money, with a much fatter midrange. Plus I've always preferred $700 junkyard replacements over built motors. And 245 hoosiers for ST4 are only $33 more per set than 225 Hoosiers for ST5. And 2250lb ST4 comp weight sounds way more fun than 2450-2500lb ST5 comp weight. And enduros will be more fun with more power, since there will be less getting passed on the straights and held up in the corners by 250hp turbo Saabs that are somehow 2 classes below me. And...
Starting with a relatively clean 2001 chassis that was someone else's failed turbo kswap drag car project. Thankfully he didn't get much farther than disassembling everything and then rattle canning the interior flat black. I bought it for $1000 last fall with no engine, transmission, or interior. Dropped my old 99 drivetrain into it so that it could be moved around easily, and then immediately took it to Mark Mcmahan in Akron for the cage. Picked it back up 2 weeks ago and have slowly been working on all the non-drivetrain stuff while I wait for my swap kit to arrive. Swap kit was ordered in December and should be shipping any day now, but I still have plenty of stuff to keep me busy.
Parts/plans:
After 10 years of mostly lurking on this forum, I've finally decided to make a build thread. I've learned a ton from this place over the years but haven't had many opportunities to give back, so I'm going to attempt to document my Ecotec swap. Most of the good ecotec information is buried in facebook right now, and... ****. That.
I'll be running this car in WRL GP1 and NASA ST4, and maybe ST5 as well with a detune and a bunch of ballast. Honestly the ecotec swap still ranks pretty low on my list of favorite miata engines, but I decided it's the best fit for my needs. The endurance racing aspect meant ruling out boost, both for reliability and fuel economy reasons. The NASA ST4/5 rules mean I have to keep the stock unmodified subframe, so Ecotec or built n/a BP were really the only two options left. A lightly built BP can make enough power for ST5, but the Ecotec makes 20-40hp more for quite a bit less money, with a much fatter midrange. Plus I've always preferred $700 junkyard replacements over built motors. And 245 hoosiers for ST4 are only $33 more per set than 225 Hoosiers for ST5. And 2250lb ST4 comp weight sounds way more fun than 2450-2500lb ST5 comp weight. And enduros will be more fun with more power, since there will be less getting passed on the straights and held up in the corners by 250hp turbo Saabs that are somehow 2 classes below me. And...
Starting with a relatively clean 2001 chassis that was someone else's failed turbo kswap drag car project. Thankfully he didn't get much farther than disassembling everything and then rattle canning the interior flat black. I bought it for $1000 last fall with no engine, transmission, or interior. Dropped my old 99 drivetrain into it so that it could be moved around easily, and then immediately took it to Mark Mcmahan in Akron for the cage. Picked it back up 2 weeks ago and have slowly been working on all the non-drivetrain stuff while I wait for my swap kit to arrive. Swap kit was ordered in December and should be shipping any day now, but I still have plenty of stuff to keep me busy.
Parts/plans:
2.4L LEA Ecotec (DBW and direct injection)
GM ecu and flex fuel sensor
1320 Performance Polaris Slingshot header. Custom 2.5" exhaust.
NB 5 speed. Currently searching for a good low miles example.
4.3 OS Giken
Still undecided on wiring. There are a few good options for custom harnesses but I'm leaning toward making my own. I'm definitely ditching all of the original miata engine and body wiring and going full racecar.
1000/500 XIDA
Sway bars TBD
Sadfab NASA bushing package
My own custom Stoptech STR-42 setup that uses cheap 11" ND miata rotors
245/40/15 Hoosier R7 for NASA
245/40/15 Hankook RS4 for WRL
Undecided on 9s or 10s. I obviously want 10s but I'm not sure I want to **** the fenders that hard. Not interested in flares.
APR GT250
Airdam, splitter, hood vents, etc
Steel OEM doors for WRL, since ballast isn't allowed and I don't want to move up to GP0.
CCP fiberglass doors for NASA and track days
CCP/TCM hardtop
AiM MXS dash for the bitches
I haven't found any sources that I consider to be 100% trustworthy, but I'm expecting 190 dynojet whp on 93 on the low end, maybe 215-220 on the high end with E85. NASA comp weight with driver will be around 2250lb. WRL comp weight will be 2150-2200 without driver.
That pretty much covers it for now. Current pics:
https://photos.app.goo.gl/LlEglGcCUEkd8dcj1
GM ecu and flex fuel sensor
1320 Performance Polaris Slingshot header. Custom 2.5" exhaust.
NB 5 speed. Currently searching for a good low miles example.
4.3 OS Giken
Still undecided on wiring. There are a few good options for custom harnesses but I'm leaning toward making my own. I'm definitely ditching all of the original miata engine and body wiring and going full racecar.
1000/500 XIDA
Sway bars TBD
Sadfab NASA bushing package
My own custom Stoptech STR-42 setup that uses cheap 11" ND miata rotors
245/40/15 Hoosier R7 for NASA
245/40/15 Hankook RS4 for WRL
Undecided on 9s or 10s. I obviously want 10s but I'm not sure I want to **** the fenders that hard. Not interested in flares.
APR GT250
Airdam, splitter, hood vents, etc
Steel OEM doors for WRL, since ballast isn't allowed and I don't want to move up to GP0.
CCP fiberglass doors for NASA and track days
CCP/TCM hardtop
AiM MXS dash for the bitches
I haven't found any sources that I consider to be 100% trustworthy, but I'm expecting 190 dynojet whp on 93 on the low end, maybe 215-220 on the high end with E85. NASA comp weight with driver will be around 2250lb. WRL comp weight will be 2150-2200 without driver.
That pretty much covers it for now. Current pics:
https://photos.app.goo.gl/LlEglGcCUEkd8dcj1
Last edited by jpreston; 11-16-2018 at 10:30 PM.
#8
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Short answer: I forgot.
Long answer: This is my second Mcmahan NB cage in 2 years.The first one only got about 4 races under its belt before getting totalled in the WRL enduro at Road America last May. Oil down in the kink is bad news. That car had a passenger seat so that I could give ride alongs while instructing, so I intentionally left the roof diagonal out for headroom reasons. I told Mark to make this cage identical to the last one except for a couple small change requests, and I forgot about the roof bar. I'll probably add it myself at some point, but that's a pretty rare crash scenario so I'm not super worried about it.
Long answer: This is my second Mcmahan NB cage in 2 years.The first one only got about 4 races under its belt before getting totalled in the WRL enduro at Road America last May. Oil down in the kink is bad news. That car had a passenger seat so that I could give ride alongs while instructing, so I intentionally left the roof diagonal out for headroom reasons. I told Mark to make this cage identical to the last one except for a couple small change requests, and I forgot about the roof bar. I'll probably add it myself at some point, but that's a pretty rare crash scenario so I'm not super worried about it.
Last edited by jpreston; 02-23-2018 at 02:36 PM.
#10
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Join Date: Dec 2008
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Tillett B6F. Details and pictures located here:
https://www.miataturbo.net/race-prep...a-84927/page4/
https://www.miataturbo.net/race-prep...a-84927/page4/
#14
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Join Date: Dec 2008
Location: KY
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I'm not sure yet. I'm going to play with spacers on a 15x9/225 and/or borrow a 15x10 from one of the Louisville guys to test fit. I need to see for myself exactly how much fender ******* is required for 10s before making the call.