Why build a 1.8BP motor?
02-17-2022, 10:53 AM
#1
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Why build a 1.8BP motor?
My argument is : Why build a miata motor to push 20+psi to hit tq/hp numbers you want, when for ~1k more you can swap in a K24 or other engine.
Push a miata motor to high intensity when a K24/V6/V8 swap would make that power with much less engine stress.
Given todays demands, sell your engine and turbo setup to someone, flip that money towards a build and gain room to expand. A turbo miata on 23-30psi is: a lot to handle, but also close to the max of engine and chassis limits. Why build a setup with no room to expand?
Interested to see others POV on this. I would like to keep the "OEM" drivetrain but just value wise doesn't make sense. I bought my engine almost 5 years ago for 600$ shipped to my door, 60k miles clean. Now I cant find a motor that's a POS for less than $800 around me.
Last edited by Dissociated; 02-17-2022 at 01:38 PM. Reason: Questions answered/Thread done
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02-17-2022, 11:26 AM
#3
Friend and I are looking for more power. After some researching, combined with current market demands... we cant justify building an Miata engine. (We're both boosted running 12psi)
My argument is : Why build a miata motor to push 20+psi to hit tq/hp numbers you want, when for ~1k more you can swap in a K24 or other engine.
Push a miata motor to high intensity when a K24/V6/V8 swap would make that power with much less engine stress.
Given todays demands, sell your engine and turbo setup to someone, flip that money towards a build and gain room to expand. A turbo miata on 23-30psi is: a lot to handle, but also close to the max of engine and chassis limits. Why build a setup with no room to expand?
Interested to see others POV on this. I would like to keep the "OEM" drivetrain but just value wise doesn't make sense. I bought my engine almost 5 years ago for 600$ shipped to my door, 60k miles clean. Now I cant find a motor that's a POS for less than $800 around me.
My argument is : Why build a miata motor to push 20+psi to hit tq/hp numbers you want, when for ~1k more you can swap in a K24 or other engine.
Push a miata motor to high intensity when a K24/V6/V8 swap would make that power with much less engine stress.
Given todays demands, sell your engine and turbo setup to someone, flip that money towards a build and gain room to expand. A turbo miata on 23-30psi is: a lot to handle, but also close to the max of engine and chassis limits. Why build a setup with no room to expand?
Interested to see others POV on this. I would like to keep the "OEM" drivetrain but just value wise doesn't make sense. I bought my engine almost 5 years ago for 600$ shipped to my door, 60k miles clean. Now I cant find a motor that's a POS for less than $800 around me.
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02-17-2022, 12:48 PM
#5
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You only need 10psi to match what a KMiata does for power, for a simple street car it's far simpler and more reliable to just do a proven turbo kit and have more power everywhere.
Swapping the engine is a big job, and it'll never be fully as reliable as an OEM base. For track use it makes sense as the engine isn't being stressed, there's less weight, and no lag.
Swapping the engine is a big job, and it'll never be fully as reliable as an OEM base. For track use it makes sense as the engine isn't being stressed, there's less weight, and no lag.
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02-17-2022, 01:26 PM
#6
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Why?
- "You're" heavily invested in the existing BP and don't want to ride the learning curve for a K, or LS swap
- "You" don't want to go through the down-time to get the swap done (and the accompanying withdrawal symptoms)
- "You" don't have the discretionary income to buy into everything needed for a swap (while the incremental cost to continue with improvements/repairs is tolerable)
- "You" looked at the swap longingly and said, "I'll do it the next time I blow this engine..."
- "Your" car is bought, not built and you just don't have the mechanical aptitude to DIY (also see #3)
- "You" are Mazda, Ride-or-Die
Last edited by rwyatt365; 02-17-2022 at 01:43 PM.
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02-17-2022, 02:56 PM
#11
Why?
- "You" don't want to go through the down-time to get the swap done (and the accompanying withdrawal symptoms)
- "You" don't have the discretionary income to buy into everything needed for a swap (while the incremental cost to continue with improvements/repairs is tolerable)
These are both very, very accurate points w/r/t the K-swap I'm doing right now. Progress has been intermittent on my swap, though not due to budget. I'm lucky enough to throw down a card and buy what I want/need for the swap, but the costs have crept far, far beyond what I initially forecasted. And had I been restricted on funds, the swap would have taken even longer.
When I started my K-swap, I was happily single and under-utilized at work. Scope crept, budget blew out, and life evolved. I don't spend nearly as much time in my garage as I did when I started the swap. I've also missed out on an entire season of HPDE/TT. If I had just dropped off an engine at a builder and written a check, I'd have missed far less track time and have been done in a couple weekends. The scope creep is really what has slowed my build, but I justify it by thinking about how reliable it will be when I'm done. Maybe one day I'll make back all the time I've lost to this "reliability" increase, but that'll take a while.
I've seen some, but heard more about the downsides of a turbocharged BP as a hardcore track machine. But those are probably smaller, bite-sized downsides compared to the big bite of "dropping" in a K engine.
I guess the short version is - please don't think the K-swap is necessarily an easy way to do things. Maybe it can be, but it's also a great way to start down a rabbit-hole of "improving" things.
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02-17-2022, 03:35 PM
#12
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Just playing along here, even if this post was designed to pad post counts.
These are both very, very accurate points w/r/t the K-swap I'm doing right now. Progress has been intermittent on my swap, though not due to budget. I'm lucky enough to throw down a card and buy what I want/need for the swap, but the costs have crept far, far beyond what I initially forecasted. And had I been restricted on funds, the swap would have taken even longer.
When I started my K-swap, I was happily single and under-utilized at work. Scope crept, budget blew out, and life evolved. I don't spend nearly as much time in my garage as I did when I started the swap. I've also missed out on an entire season of HPDE/TT. If I had just dropped off an engine at a builder and written a check, I'd have missed far less track time and have been done in a couple weekends. The scope creep is really what has slowed my build, but I justify it by thinking about how reliable it will be when I'm done. Maybe one day I'll make back all the time I've lost to this "reliability" increase, but that'll take a while.
I've seen some, but heard more about the downsides of a turbocharged BP as a hardcore track machine. But those are probably smaller, bite-sized downsides compared to the big bite of "dropping" in a K engine.
I guess the short version is - please don't think the K-swap is necessarily an easy way to do things. Maybe it can be, but it's also a great way to start down a rabbit-hole of "improving" things.
These are both very, very accurate points w/r/t the K-swap I'm doing right now. Progress has been intermittent on my swap, though not due to budget. I'm lucky enough to throw down a card and buy what I want/need for the swap, but the costs have crept far, far beyond what I initially forecasted. And had I been restricted on funds, the swap would have taken even longer.
When I started my K-swap, I was happily single and under-utilized at work. Scope crept, budget blew out, and life evolved. I don't spend nearly as much time in my garage as I did when I started the swap. I've also missed out on an entire season of HPDE/TT. If I had just dropped off an engine at a builder and written a check, I'd have missed far less track time and have been done in a couple weekends. The scope creep is really what has slowed my build, but I justify it by thinking about how reliable it will be when I'm done. Maybe one day I'll make back all the time I've lost to this "reliability" increase, but that'll take a while.
I've seen some, but heard more about the downsides of a turbocharged BP as a hardcore track machine. But those are probably smaller, bite-sized downsides compared to the big bite of "dropping" in a K engine.
I guess the short version is - please don't think the K-swap is necessarily an easy way to do things. Maybe it can be, but it's also a great way to start down a rabbit-hole of "improving" things.
I probably should've clarified also that I wasn't looking to pick apart every aspect. The infinite variables of time, parts, availability, money, etc. will obviously be a topic for debate forever. My post was to talk about in todays market, with the proper budget. Spending 10k for an engine at 95% or spend 11k for another at 20%.
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02-19-2022, 01:05 AM
#14
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Because in all honesty, it's not that expensive and it's not that challenging if you put in the research.
The tools to do it properly aren't gonna drain your wallet either. Rod bolt stretch gauges can be had for $30. ring compressors are cheap. Rods can be found for what, $100 each nowadays? The most expensive part really seems to be pistons and getting machine work done.
My machine work ended up being pricey, but that's because I had to get it line bored to fit new main bearing caps in addition to boring the cylinders to 84mm. But I can't complain, I got the block and pristine head for $150. And this is in California, where Miatas and Miata parts are "outrageously" priced. Just find good deals.
The tools to do it properly aren't gonna drain your wallet either. Rod bolt stretch gauges can be had for $30. ring compressors are cheap. Rods can be found for what, $100 each nowadays? The most expensive part really seems to be pistons and getting machine work done.
My machine work ended up being pricey, but that's because I had to get it line bored to fit new main bearing caps in addition to boring the cylinders to 84mm. But I can't complain, I got the block and pristine head for $150. And this is in California, where Miatas and Miata parts are "outrageously" priced. Just find good deals.
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02-19-2022, 12:24 PM
#15
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I found in my search that most non-BP swaps were cool but ALWAYS costed so much more money. There is a lot of work with subframe, Matching a trans, working on an unknown platform, wiring. I just didn't see it worth it when I saw people on here and people like Greg Peters making over 400 to the wheels on a built BP. Do I think there are better swaps? absolutely. Are there better swaps for the cost? ehhh, that's subjective.
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