ChrisTropea
ChrisTropea Associate Editor
1/8/21 1:03 p.m.

https://www.youtube.com/embed/uWNxnQl8nzg

Mentioning V8 Roadsters may conjure up images of a massive V8 stuffed into a NA Miata, but the company also produces kits that slot the Chevrolet LFX V6 into a number of popular Mazda products–a kit we decided to use for our budget MX-5 endurance racer.

We recently compared two of the company’s swaps: an automatic Mazda RX-8 and a manual NC-chassis Mazda MX-5? Presented by CRC Industries.

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noddaz
noddaz UltraDork
1/8/21 1:06 p.m.

Yes.

Tom Suddard
Tom Suddard Director of Marketing & Digital Assets
1/8/21 1:52 p.m.

It didn't make it into the video, but after shooting wrapped I took the MX-5 out again for a few laps with revised tire pressures and shock tuning, and WOW did that make it a closer competition. The answer really is "Both"

spacecadet (Forum Supporter)
spacecadet (Forum Supporter) UltraDork
1/8/21 2:05 p.m.

Cool video, I liked the intro by SUPER EXCITED TOM.

Raze (Forum Supporter)
Raze (Forum Supporter) UltraDork
1/8/21 2:47 p.m.

what's the cost/weight/size diff on the RX8 LFX vs a 6th Gen V6 Camaro?  

Tom Suddard
Tom Suddard Director of Marketing & Digital Assets
1/8/21 3:46 p.m.

In reply to Raze (Forum Supporter) :

I'm going from memory here, but I think the difference is about 300 pounds. The size difference is HUGE though. It's just a drastically different scale for a car. The Camaro is about 6" wider and more than a foot longer.

Keith Tanner
Keith Tanner MegaDork
1/8/21 3:48 p.m.
Raze (Forum Supporter) said:

what's the cost/weight/size diff on the RX8 LFX vs a 6th Gen V6 Camaro?  

Okay, that made me laugh out loud. It's an excellent question to ask.

BlueInGreen - Jon (Forum Supporter)
BlueInGreen - Jon (Forum Supporter) UltraDork
1/8/21 3:56 p.m.

Plus, you can see out of an RX8 :P

Now just need to do an old school version of this comparison: Dusterbd13’s $2000 challenge V6 Miata and wvumtnbkr’s  V6 RX7 Champcar.

Rodan
Rodan Dork
1/8/21 5:06 p.m.

All that video and we don't get to hear what they sound like?  Shame.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) Dork
1/8/21 7:13 p.m.

But isn't an LS1 version of each even better?  Next video?

wvumtnbkr
wvumtnbkr PowerDork
1/8/21 7:15 p.m.
BlueInGreen - Jon (Forum Supporter) said:

Plus, you can see out of an RX8 :P

Now just need to do an old school version of this comparison: Dusterbd13’s $2000 challenge V6 Miata and wvumtnbkr’s  V6 RX7 Champcar.

I'm in!

Keith Tanner
Keith Tanner MegaDork
1/9/21 4:25 p.m.
AnthonyGS (Forum Supporter) said:

But isn't an LS1 version of each even better?  Next video?

This is the question about LFX swaps. It's as much work as an LS swap - at least with these two cars. It's a bit lighter but not massively. There is a significant power difference. Is it worth doing the V6 in that case? 

Now, if you can retain pieces of the stock drivetrain while staying reliable, that's a different matter. But then you're dealing with a car that probably already came from the factory with a fair amount of power, otherwise the stock parts will be overstressed.

aircooled
aircooled MegaDork
1/9/21 5:34 p.m.
BlueInGreen - Jon (Forum Supporter) said:

Plus, you can see out of an RX8 :P

There is probably more interior room in the RX8, and WAY nicer rear seats.

 

wspohn
wspohn SuperDork
1/10/21 11:44 a.m.

I would think that the logical alternative to a V6 swap wouldn't be a V8, which may pose more packaging challenges, but a modern turbo I4 engine which can produce more power and torque than the LFX with a mild bit of tuning, is lighter and takes up less space.

Keith Tanner
Keith Tanner MegaDork
1/10/21 1:06 p.m.

Turbos are heavier and bulkier than you think. It would be interesting to get actual weights and dimensions on a turbo 4 and an aluminum V6 of similar power. 

The Fiat 124 Spider is 100 lbs heavier than the ND Miata, for example. All of the extra weight is on the front wheels. 

kb58
kb58 SuperDork
1/10/21 3:51 p.m.

Have to agree with Keith on turbo weight. You have to be ruthless about including all weights in the system so you aren't deluding yourself. Turbo, exhaust manifold, tubing, intercooler, all that stuff may easily end up at 50 lbs.

Snrub
Snrub Dork
1/10/21 7:55 p.m.

The 6th-gen Camaro has a turbo I4 and the LFX, with not dissimilar power under the curve. I believe the weight difference is ~100lbs. 

I may be mistaken, but I believe the 1.4L Turbo Fiat engine has an iron block. I recall some commenting on how thin the castings are on the ND's 2.0L. Some of the weight difference is also in the 124's NC-based transmission vs. the ND, but I'm guessing that was done to handle the higher torque output. I'm guessing modern 4-cyl turbo setups add 50-60lbs (?).

Keith Tanner
Keith Tanner MegaDork
1/10/21 8:19 p.m.

There's no question that the ND Miata engine has undergone ruthless weight control. But still, 100 lbs. That's not just block design/material. If the trans is heavier, that weight does not show up on the rear wheels at all. I think I have weights of the transmissions somewhere. I think it does illustrate the extra mass from a cast iron turbo manifold, turbocharger and intercooler/piping.

The two Cameros are probably another good comparison.

Vigo (Forum Supporter)
Vigo (Forum Supporter) MegaDork
1/12/21 8:50 a.m.

Call me crazy but i feel like the main advantage of going with a low-torque not-a-v8 option is to leave everything from the bellhousing back completely alone, or at least have the option to! I'm not crazy about the trans used behind the 3.6 from my CTS repair experiences anyway, although I don't have much memory of noticing anything about it from driving 5th gen Camaros (?). Hopefully the "non serviceable" shifter bushings are more accessible in an RX8? 

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