SCCA CAM-C Thread

[Brian@BMVK]

There must be more thrust within the EB power band at autox speeds in 3rd for them than top of 2nd/bottom of 3rd with stock gearing. The car also has 18" wheels and guessing 25.x" diameter Yokos to contribute to this performance.

I saw this video on fb so asked a question about what it weighs there.

Well, the EB power band is from 3-6k rpm, rather than 4.5-7.5k for the Coyote. Shifting up to 3rd to stay in that probably makes sense.

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[TeeLew]

This is the same question I've been wrestling with. Their Eco is a 2015, so it presumably has the lower transmission gear ratios. Mine has the later, taller gears. I'm going to play around with the ratios to see how they stack up. Without looking at their setup, I'm interested in trying the 3.31, because I do think that would be an improvement.

I think it's worth mentioning that they were _not_ on a typical autocross parking lot course. That was one hell of a fast course.

 

[Brian@BMVK]

This is the same question I've been wrestling with. Their Eco is a 2015, so it presumably has the lower transmission gear ratios. Mine has the later, taller gears. I'm going to play around with the ratios to see how they stack up. Without looking at their setup, I'm interested in trying the 3.31, because I do think that would be an improvement.

I think it's worth mentioning that they were _not_ on a typical autocross parking lot course. That was one hell of a fast course.

Agreed, I saw a few clips and I would have been in 3rd gear as well.

 

[shogun32]

I'm interested in trying the 3.31, because I do think that would be an improvement.

so you want to go taller vs the stock 3.55?

 

[kz]

I think it's worth mentioning that they were _not_ on a typical autocross parking lot course. That was one hell of a fast course.

Seemed to be typical national course (which this was) speed-wise. Last year I was at least twice on the limiter (~72 mph) on two different events in Peru. We even had a local event on much smaller lot where I was on the limiter but that was just stupid course design.

 

[TeeLew]

Here's what I'm seeing on the Eco gearing.

Steeda 2015 car with 3.31 rear gear and A052 305/R18 tires @ 6500 rpm:
2nd - 59.6 mph
3rd - 86.0 mph

Steeda 2015 car with 3.73 rear gear and A052 305/R18 tires @ 6500 rpm:
2nd - 52.9 mph
3rd - 76.3 mph

My 2020 car with 3.55 (stock) rear gear and RE-71R 305/R19 tires @ 6500 rpm:
2nd - 65.8 mph
3rd - 97.4 mph

My 2020 with 3.31 rear gear and RE-71R 305/R19 tires @ 6500 rpm:
2nd - 70.6 mph
3rd - 104.5 mph

My 2020 with 3.15 rear gear (that does not fit my differential and is not really an option to use)
2nd - 74.2 mph

I think the Steeda gearing is pretty much bang-on. I was thinking a gear which goes to ~75 mph would be perfect and that's what they are using.

 

[TeeLew]

Seemed to be typical national course (which this was) speed-wise. Last year I was at least twice on the limiter (~72 mph) on two different events in Peru. We even had a local event on much smaller lot where I was on the limiter but that was just stupid course design.

I'm riding the limiter at least once, and often more times, per lap where I run, but at ~65 mph. I end up working between 2nd and 3rd. 3rd is really nice for faster corners, but doesn't work in the slower ones and the upshift/downshift timing can be an issue.

 

[TeamSteeda]

Interesting they went for 3.73 and 3rd. I saw they signed up for Dixie Tour - they'll have some good east coast competition, so we'll see how they do. Also it'll be interesting to know what that car weighed at (they mentioned K-member) but given how test that test PS1 event was ;-) , they may not have been doing scales there.

Yes, we're definitely looking forward to Dixie Tour. The Pro Solo event didn't have scales, however, we weighed the car ahead of the competition in prep for the scales being there. Came in at 3,363 lbs without fuel or driver. We do intend to be closer to minimum weight for the Dixie National Tour next month. Should be exciting to see how things turn out against the stiff competition!

There must be more thrust within the EB power band at autox speeds in 3rd for them than top of 2nd/bottom of 3rd with stock gearing. The car also has 18" wheels and guessing 25.x" diameter Yokos to contribute to this performance.

I saw this video on fb so asked a question about what it weighs there.

Answered weight above. And yeah, I found out the hard way that it's much better to shift into 3rd on these fast courses. 18" short wheels don't help our case either.

Well, the EB power band is from 3-6k rpm, rather than 4.5-7.5k for the Coyote. Shifting up to 3rd to stay in that probably makes sense.

Exactly!

I'm riding the limiter at least once, and often more times, per lap where I run, but at ~65 mph. I end up working between 2nd and 3rd. 3rd is really nice for faster corners, but doesn't work in the slower ones and the upshift/downshift timing can be an issue.

Great point. It's gotten to the point that we actually may need to swap the diff/gears out depending on the event we plan to run. i.e. autocross vs track event.

 

[TeeLew]

Answered weight above. And yeah, I found out the hard way that it's much better to shift into 3rd on these fast courses. 18" short wheels don't help our case either.

Didn't help you case in what respect?

Fairly minor engine mods will let the Eco pull to 6500 RPM without nosing over and you pick up bottom end torque as well. I don't think it's advisable to run higher than 6500 if you have a stock block. I highly recommend checking out what you can do here.

 

[Norm Peterson]

Didn't help you case in what respect?

Short tires are very likely to end up costing you more shifting. Autocrossing with a 'short' 2nd gear you'd be even more likely to need 3rd from time to time.


Norm

 

[Brian@BMVK]

Here's what I'm seeing on the Eco gearing.

Steeda 2015 car with 3.31 rear gear and A052 305/R18 tires @ 6500 rpm:
2nd - 59.6 mph
3rd - 86.0 mph

Steeda 2015 car with 3.73 rear gear and A052 305/R18 tires @ 6500 rpm:
2nd - 52.9 mph
3rd - 76.3 mph

My 2020 car with 3.55 (stock) rear gear and RE-71R 305/R19 tires @ 6500 rpm:
2nd - 65.8 mph
3rd - 97.4 mph

My 2020 with 3.31 rear gear and RE-71R 305/R19 tires @ 6500 rpm:
2nd - 70.6 mph
3rd - 104.5 mph

My 2020 with 3.15 rear gear (that does not fit my differential and is not really an option to use)
2nd - 74.2 mph

I think the Steeda gearing is pretty much bang-on. I was thinking a gear which goes to ~75 mph would be perfect and that's what they are using.

This is why I'm considering 3.31.

305/30R19 tire and 7500 RPM in 2nd gear would be 70.6 mph: just about perfect for most courses including national level. May require a lift/limiter hit rarely.

Right now I hit 63 mph in 2nd gear w/ 3.73s.

 

[strengthrehab]

This is why I'm considering 3.31.

305/30R19 tire and 7500 RPM in 2nd gear would be 70.6 mph: just about perfect for most courses including national level. May require a lift/limiter hit rarely.

Right now I hit 63 mph in 2nd gear w/ 3.73s.

Same

 

[TeeLew]

Short tires are very likely to end up costing you more shifting. Autocrossing with a 'short' 2nd gear you'd be even more likely to need 3rd from time to time.


Norm

OK, I thought Chris was talking about using 3rd and it confused me.

 

[kz]

Yes, we're definitely looking forward to Dixie Tour. The Pro Solo event didn't have scales, however, we weighed the car ahead of the competition in prep for the scales being there. Came in at 3,363 lbs without fuel or driver. We do intend to be closer to minimum weight for the Dixie National Tour next month. Should be exciting to see how things turn out against the stiff competition!

Thanks for answering - that is really low (most cars are 3500-3600ish at least) - where did your weight saving came mostly from as it doesn't seem to be too extreme of a build (short of replacing front subframe which is little bit of work) ?

Congrats on good results at FIRM - it's nice to see you a "factory" team showing parts they sell actually work.

 

[TeamSteeda]

Didn't help you case in what respect?

Fairly minor engine mods will let the Eco pull to 6500 RPM without nosing over and you pick up bottom end torque as well. I don't think it's advisable to run higher than 6500 if you have a stock block. I highly recommend checking out what you can do here.

We're actually pretty much full bolt-on right now running it as safe as we can to keep temps down when we run at tracks like Sebring. We use this car for parts durability testing and are willing to give up a little power/performance to keep it alive. That's why, with our current power mods, we were looking to shift into 3rd gear to get more grunt down low.

By running those short tires, it only compounds our problem with 2nd gear the lack of usable power after 5,500 RPM. Bumping to 3.73s, we can shift into 3rd sooner, stay in it longer, AND have more low-end grunt coming out of slower corners that [hopefully] don't require us to downshift back into 2nd. Hope this helps!

Thanks for answering - that is really low (most cars are 3500-3600ish at least) - where did your weight saving came mostly from as it doesn't seem to be too extreme of a build (short of replacing front subframe which is little bit of work) ?

Congrats on good results at FIRM - it's nice to see you a "factory" team showing parts they sell actually work.

It's actually not that difficult - I was surprised, too, when we put it on the scales as Jamie (our head tech) is the mastermind behind this build. Anyways, it's got lighter brakes, lighter wheels & tires, dumped exhaust, and no back seat. I'm sure there's more, but that's what I've got off the top of my head.

Thanks so much - we take pride in beating the crap out of these parts so we know they'll stand the test of time. Many of us here eat, sleep, and breathe Mustangs

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