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kevlarcorolla
kevlarcorolla Dork
7/15/24 5:20 p.m.

In reply to Keith Tanner :

I think that car mostly exists already in the form of a Z4 :)

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/15/24 5:29 p.m.

In reply to kevlarcorolla :

At a fairly significant weight penalty :) The BMW is right about 1000 lbs heavier. I think it might be failing the "small car" test.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
7/15/24 7:11 p.m.
Floating Doc (Forum Supporter) said:
Curtis73 (Forum Supporter) said:

In reply to Keith Tanner :

I'll toss you the keys for fun runs

Sign me up!

Your reservation is confirmed.

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
7/15/24 9:16 p.m.
jharry3 said:

NA/NB Miata with a Honda V-6?     The OZ kit looks better thought out than the other one.

That's a nice setup and all, but after driving many Hondas equipped with said V6, it doesn't really accelerate.  It pulls very well, don't get me wrong, but it doesn't seem like it wants to accelerate quickly like, say, a GM or Chrysler 3.6l.  Especially the GM, that engine seems very enthusiastic about wanting to accelerate.

The lighter the car, the more you want an engine that accelerates well.  Or have really tall gearing so the engine doesn't need to.  I am reminded of my Subaru that would pull harder in 2nd gear than 1st because the engine wasn't able to accelerate much, zero to redline in 1st gear was almost as quick as idle to redline in Neutral.  Or the quote about when they tried to put Allison aircraft engines in dragsters... "It won't accelerate but it will taxi all day long at 150"

It may have something to do with variable cam timing, which Hondas don't have but pretty much everything newer does.  Honda engineered themselves into a corner with that engine.  VTEC only gets you so far.

kevlarcorolla
kevlarcorolla Dork
7/15/24 10:06 p.m.

In reply to Keith Tanner :

How much heavier will a miata be with an extended front like you suggested and that powertrain plopped in?

 Probably near that 1000 lbs :)

pinchvalve (Forum Supporter)
pinchvalve (Forum Supporter) GRM+ Memberand MegaDork
7/15/24 11:08 p.m.

I don't see the need for big engine swaps since turbocharging. The GRC has a 3cyl that puts out 300hp and as many torques. Why would I want to drop a 3.0L NA engine in there?  These days, the 2.0L in the CTR is considered a big block next to the 1.5 in the Si. IMHO, the next wave of "big motor" swaps will be Tesla drive trains into other cars. 

 

RevRico
RevRico GRM+ Memberand MegaDork
7/15/24 11:21 p.m.

I always thought the 4bt Miata was cool

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/16/24 1:15 a.m.
kevlarcorolla said:

In reply to Keith Tanner :

How much heavier will a miata be with an extended front like you suggested and that powertrain plopped in?

 Probably near that 1000 lbs :)

Considering we could get an LS drivetrain with a T56 into an NA Miata with about a 200 lb weight gain, I think we'll still be able to sneak the big Skyactiv conversion in under 1000 lbs ;) 

The Tesla swap is already the big motor swap of today. They're still not the cheapest - batteries cost real money - but boy howdy do they go.

kevlarcorolla
kevlarcorolla Dork
7/16/24 6:22 a.m.

In reply to Keith Tanner :

Ls is light compared to a turbo'd straight 6 hybrid I thought we were talking about.

DeadSkunk  (Warren)
DeadSkunk (Warren) MegaDork
7/16/24 8:06 a.m.

SBC/Tremec in a 1st gen MINI with 3-series BMW rear suspension...do the same , but utilize an aluminum LS. I saw this one on Hot Rod Power Tour when it stopped at National Trail Raceway, in Ohio.

jmabarone
jmabarone HalfDork
7/16/24 8:18 a.m.
Keith Tanner said:

NC Miata with a 2.5 MZR is a popular one.

2.5 MZR is top of mind for next engine in my Ranger.  

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/16/24 10:25 a.m.
kevlarcorolla said:

In reply to Keith Tanner :

Ls is light compared to a turbo'd straight 6 hybrid I thought we were talking about.

True, which is one reason why we love it. But those Skyactiv engines are light. The engine block of the 2.0 looks like it has no body fat, you can see all the coolant passages on it. The four cylinder is only 290 lbs fully dressed with all accessories, oil, flywheel/clutch and the wiring harness. I'm assuming the same care was taken with the newer straight six, even it does have a turbo and an electric motor.  Half a ton! That's a serious weight budget.

When we were building the LS Miatas, some people asked "why not just buy a Corvette?". The answer was "because it's not a Corvette in any way other than having the same engine". I suspect the same could be said about a Z4 vs our hypothetical Miata to a smaller degree.  It was pointed out to me recently that the Porsche Cayman is a much more refined, quieter car than a Miata and that's why it gets to be considerably heavier. I expect the BMW may be the same.

EricM
EricM UltraDork
7/16/24 10:58 a.m.

Turbo

 

That's just my opinion.   I think to get "big" out of a small car is to add boost.

Recon1342
Recon1342 UltraDork
7/16/24 11:32 a.m.

One of my dreams in high school was to build a T-bucket powered by a 426 Hemi. 

I understand that small engines are more efficient, turbos=power, etc, etc...

But they just don't have the chutzpah of a big block turning 2k rpm and loping down the highway  at ~80mph.

 

Full disclosure- most of the motorsports I am interested in involve off road shenanigans, so for a street car I would want a cruiser...

dr_strangeland
dr_strangeland GRM+ Memberand Reader
7/16/24 11:58 a.m.
Keith Tanner said:
kevlarcorolla said:

In reply to Keith Tanner :

How much heavier will a miata be with an extended front like you suggested and that powertrain plopped in?

 Probably near that 1000 lbs :)

Considering we could get an LS drivetrain with a T56 into an NA Miata with about a 200 lb weight gain, I think we'll still be able to sneak the big Skyactiv conversion in under 1000 lbs ;) 

This sounds suspiciously like you've done more than just think idly about this swap. Are you looking for a donor? 

Tom1200
Tom1200 PowerDork
7/16/24 4:04 p.m.
EricM said:

Turbo

 

That's just my opinion.   I think to get "big" out of a small car is to add boost.

Lets take my Datsun 1200 as an example:

Adding a turbo to the very light A-series engine would result in a 1685lb car with 225whp.

Adding a small block V8 would result in a 1890lb car that would easily put out 300whp. 

The turbo motored car would run about 100hrs between rebuilds whereas the V8 powered car would 100k before it needed rebuilding. 

V8s just make sense. I say this as someone is really isn't a fan of V8s.

accordionfolder
accordionfolder UltraDork
7/17/24 1:22 p.m.

In reply to Tom1200 :

Agreed, v6/v8 - heat management on an under-stressed - all OEM build that makes 270+whp from a track perspective makes a ton more sense. I literally bought a 350whp engine w/ a warranty brand new from chevy. My car weighs 2400lbs and has a transmission made to support 700+wtq in a 3000+lb vehicle. My engine literally thinks it's on a chassis dyno. 

 

 

gsettle
gsettle Reader
7/17/24 1:40 p.m.

In reply to accordionfolder :

Looks like you got NCM all to your self for this shakedown....

How'd you pull that off??

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/17/24 1:52 p.m.
Tom1200 said:
EricM said:

Turbo

 

That's just my opinion.   I think to get "big" out of a small car is to add boost.

Lets take my Datsun 1200 as an example:

Adding a turbo to the very light A-series engine would result in a 1685lb car with 225whp.

Adding a small block V8 would result in a 1890lb car that would easily put out 300whp. 

The turbo motored car would run about 100hrs between rebuilds whereas the V8 powered car would 100k before it needed rebuilding. 

V8s just make sense. I say this as someone is really isn't a fan of V8s.

There's also this. Boost vs displacement, a crate LS3 versus a built 2.0 with a big turbo. Total cost was pretty much the same with pros doing to work. The peaks aren't that different but you can bet one's more effective. That turbo motor can go a lot more than 100 hours between rebuilds - that's off by at least an order of magnitude - but just check that torque. The biggest advantage the turbo engine has here is that you can approach it bit by bit, gradually adding parts. The V8 is a single big leap.

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/17/24 1:55 p.m.
dr_strangeland said:
Keith Tanner said:
kevlarcorolla said:

In reply to Keith Tanner :

How much heavier will a miata be with an extended front like you suggested and that powertrain plopped in?

 Probably near that 1000 lbs :)

Considering we could get an LS drivetrain with a T56 into an NA Miata with about a 200 lb weight gain, I think we'll still be able to sneak the big Skyactiv conversion in under 1000 lbs ;) 

This sounds suspiciously like you've done more than just think idly about this swap. Are you looking for a donor? 

Not at all. If we were talking about, say, a 400 lb mass allowance I'd be less confident. 1000 lbs is close to a 50% weight gain so I think someone could pull it off if they wanted. I don't want :) I used the LS Miata as an example because that's a well-known swap with actual weights available.

accordionfolder
accordionfolder UltraDork
7/17/24 2:05 p.m.
gsettle said:

In reply to accordionfolder :

Looks like you got NCM all to your self for this shakedown....

How'd you pull that off??

I used to be part of the Driving Club up there - I got a lot of seat time, but it was a bit boring after the third year. 

gsettle
gsettle Reader
7/17/24 2:49 p.m.

Nice... What was the Miata's lap time there?

accordionfolder
accordionfolder UltraDork
7/17/24 3:23 p.m.

In reply to gsettle :

I think I managed a 2:16 at one point with 245 ToyoRR's on it (i.e. complete garbage for absolute lap times) - but it had a whole lot more in it when I get the brakes working like I want. That was when we were still fighting setup and the rest. I have a video, but I had so much roll stiffness in the front that I wasn't able to get it to turn, later on during TTNats that year we got it mostly acting right (still on toyos though), but it's kinda fallen off the bandwagon this year as I've been mainly playing with my spec miata and my TT6 Miata (VVT).  I have some big hoho's for it to try out - so hopefully we'll go a bit faster.

You can see me absolutely torqing the wheel and the front end just not doing what I want.
 

 

Tom1200
Tom1200 PowerDork
7/17/24 4:05 p.m.

In reply to Keith Tanner :

To clarify: the 100 hour rebuild is the maintenance interval for a 200+ horsepower Datsun 1200 A-series engine, not a  modern turbo engine. 

 

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
7/17/24 4:12 p.m.

In reply to Tom1200 :

Ah yes. IIRC that's related to the BMC A series, for which there are many hand grenade recipes.

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