Turbo BP vs Low Power Engine Swaps
#21
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Thank you guys for all the inputs! So I'll just go top to bottom. I don't plan on making 250whp on a K Swap. With a build its possible but I was saying that in any circumstance I dont want to exceed 250whp. I have a '09 STI with 300whp and even though its 1000lbs heavier, 300whp has been enough for me on the track. I completely agree that mechanical empathy and research will prevent failures. If the K Swap is maybe $1-2k more than a reliable turbo build, is it worth not having to deal with the slightly more complex turbo system in a BP? As well as the weight savings. Im not saying a K Swap drops 100lbs but accessories aside the K swap drops 30lbs over the BP and that doesnt even include the turbo kit. It might sound like im being biased to the K Swap but im just trying to make an educated decision with help from you guys before I drop $$$$ on anything.
#22
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Where in the Midwest are you? We can definitely throw you in the right seat of one of our cars on track this year if you want to experience a K24 swap first hand. We'll have a couple cars at the Gridlife festival and a bunch of other local events.
We've dialed in the K swap very well over the last 3 years. The current package is extremely reliable and works well with the factory drivetrain. figure 220whp for a stock k24a2 swap. If you want to see around 250whp, you'll need a k20a2 head, some big cams, and maybe e85. We made 248whp on 93 with a setup like this a couple years ago.
If you have specific questions you can hit me up via email anytime at sales@kmiata.com or call the shop to chat.
We've dialed in the K swap very well over the last 3 years. The current package is extremely reliable and works well with the factory drivetrain. figure 220whp for a stock k24a2 swap. If you want to see around 250whp, you'll need a k20a2 head, some big cams, and maybe e85. We made 248whp on 93 with a setup like this a couple years ago.
If you have specific questions you can hit me up via email anytime at sales@kmiata.com or call the shop to chat.
#24
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#25
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two completely different uses you're describing. I agree that being able to beat on a car, explore limits of cornering, drive flat out 10/10 is a whole lot of fun.
Then you drive that same car daily or on flat/straight roads and it's so boring you fall asleep at the wheel.
Meanwhile a fat torquey turbo powerband will keep most below 20% throttle in the twisties because both the car and the driver are simply overpowered, which does get frustrating in the corners from time to time, but feels a-ma-zing daily driving and in "point and shoot" situations and suddenly the situation is backwards.
Why not have both?
Then you drive that same car daily or on flat/straight roads and it's so boring you fall asleep at the wheel.
Meanwhile a fat torquey turbo powerband will keep most below 20% throttle in the twisties because both the car and the driver are simply overpowered, which does get frustrating in the corners from time to time, but feels a-ma-zing daily driving and in "point and shoot" situations and suddenly the situation is backwards.
Why not have both?
![big grin](https://www.miataturbo.net/images/smilies/biggrin.gif)
#26
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Thank you guys for all the inputs! So I'll just go top to bottom. I don't plan on making 250whp on a K Swap. With a build its possible but I was saying that in any circumstance I dont want to exceed 250whp. I have a '09 STI with 300whp and even though its 1000lbs heavier, 300whp has been enough for me on the track. I completely agree that mechanical empathy and research will prevent failures. If the K Swap is maybe $1-2k more than a reliable turbo build, is it worth not having to deal with the slightly more complex turbo system in a BP? As well as the weight savings. Im not saying a K Swap drops 100lbs but accessories aside the K swap drops 30lbs over the BP and that doesnt even include the turbo kit. It might sound like im being biased to the K Swap but im just trying to make an educated decision with help from you guys before I drop $$$$ on anything.
Kswap you're looking at about $10k+ realistically. Yes I'd love one, but I'd argue the cost isn't as close as you think for a recreational HPDE build. If we're talking actual racecar then things start to even out as a turbo bp needs a few more things to handle that level of driving.
#27
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Kswap you're looking at about $10k+ realistically. Yes I'd love one, but I'd argue the cost isn't as close as you think for a recreational HPDE build. If we're talking actual racecar then things start to even out as a turbo bp needs a few more things to handle that level of driving.
__________________
KPower Industries
Home of the original KMiata Swap
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K24 NC swap is coming in 2024! Learn more
info@kpower.industries
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KPower Industries
Home of the original KMiata Swap
![](https://www.miataturbo.net/signaturepics/sigpic27665_14.gif)
K24 NC swap is coming in 2024! Learn more
info@kpower.industries
Follow us on Facebook and Instagram
#28
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I’m kind of on the side of the K being a newer design and more stout. I’ve also looked online and after radiator, clutch, and e85 system the turbo kit runs around $7.5k. I’ve check the same for the Kswap and online it turns out to be around $8.5k. Both of these figures are with everything included except tune. Anything about the J Swap? By far the least interest but I’d still like to hear
#32
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I know Justin @ Thing 3 Racing (https://www.thing3racing.com/) runs a J32 in his AER/WRL Endurocar. User name slammed200.
Last edited by Midtenn; 03-22-2018 at 04:31 PM. Reason: Found the user name
#33
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Calling Justin Lee to the J-swapped Miata courtesy phone...
@slammed200
If anyone knows a thing or two about the J-swap, I'm guessing it's Justin. He's the only one I know of seriously racing and pushing a j-Miata to the limit.
@slammed200
If anyone knows a thing or two about the J-swap, I'm guessing it's Justin. He's the only one I know of seriously racing and pushing a j-Miata to the limit.
Last edited by Efini~FC3S; 03-23-2018 at 09:32 AM. Reason: phone type Os
#34
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So hey guys I’ve had my Miata for almost 8 months now. I’ve been steadily learning how to push it to the limits while simultaneously increasing performance as well as safety mods. I plan on starting to track my car very consistently (I know the related costs).
Reliability and seat time are my main concerns.
Reliability and seat time are my main concerns.
Chiming in here from an endurance race team owner's perspective, reliability and seat time are huge. I also hesitate to recommend that ANYONE add a single horsepower when learning how to drive on track. Honestly, and this is always the last thing anyone wants to hear, power doesn't help you become a better driver. I'll get off my pedal-stool now since that's not what you asked but...
Now - about the J swap. I've had to completely redo just about every aspect of the J swap components to make it suitable for endurance racing and to my knowledge I'm the only one racing it regularly in these types of events. It's a hell of a car to drive now after all of that, smooth torques for days on days, but getting here wasn't easy at all. I'm not going to comment on the other options listed other than to say simple is sweet but you can swing that tradeoff based on your goals. Reliability and seat time are my main concerns.
#35
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^ good advice here.
You didn’t say much about your track goals in the OP, or if you’ve even been on the track at all yet. If your plan is just to do HPDE/track days and you’re not trying to shave seconds off of lap times, just get out there and do it in a stock car. Trust me the car won’t be holding you back.
I’m going down this path right now with a turbo 1.6L, making 170-180 hp. No reliability issues at all so far, and the car is plenty fast/fun. I have absolutely no need or use for more power in the foreseeable future.
Building a car for fun on the track is a totally different set of priorities than building a car for lap times or racing. I don’t think you can have more fun than throwing a stock Miata on street tires around a track.
You didn’t say much about your track goals in the OP, or if you’ve even been on the track at all yet. If your plan is just to do HPDE/track days and you’re not trying to shave seconds off of lap times, just get out there and do it in a stock car. Trust me the car won’t be holding you back.
I’m going down this path right now with a turbo 1.6L, making 170-180 hp. No reliability issues at all so far, and the car is plenty fast/fun. I have absolutely no need or use for more power in the foreseeable future.
Building a car for fun on the track is a totally different set of priorities than building a car for lap times or racing. I don’t think you can have more fun than throwing a stock Miata on street tires around a track.
#39
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two completely different uses you're describing. I agree that being able to beat on a car, explore limits of cornering, drive flat out 10/10 is a whole lot of fun.
Then you drive that same car daily or on flat/straight roads and it's so boring you fall asleep at the wheel.
Meanwhile a fat torquey turbo powerband will keep most below 20% throttle in the twisties because both the car and the driver are simply overpowered, which does get frustrating in the corners from time to time, but feels a-ma-zing daily driving and in "point and shoot" situations and suddenly the situation is backwards.
Why not have both?![big grin](https://www.miataturbo.net/images/smilies/biggrin.gif)
Then you drive that same car daily or on flat/straight roads and it's so boring you fall asleep at the wheel.
Meanwhile a fat torquey turbo powerband will keep most below 20% throttle in the twisties because both the car and the driver are simply overpowered, which does get frustrating in the corners from time to time, but feels a-ma-zing daily driving and in "point and shoot" situations and suddenly the situation is backwards.
Why not have both?
![big grin](https://www.miataturbo.net/images/smilies/biggrin.gif)
For the most part, I track a 949 95R project clone. Pretty much SuperMiata S2 specification. Fantastic track car that never misses a beat.
Sometimes I'll borrow my daughter's '15 PRHT GT with all the bells and whistles for date night.
You can never have enough Miatas. Are the '19s out yet?
#40
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Not to toot my own horn, but if you built a reliable turbo car before 2015, you did it with an engineering degree or an extreme amount of persistence. It was certainly doable, but it was not formulaic like it has become in the last ~2yrs or so. The fact that you can buy off-the-shelf components from Trackspeed and build a reliable turbo car in your garage is a relatively new thing.