Dilemma: Will turbo make 1st gear useless for autocross?
 

I autocrossed my friends NB with 225 rivals on 15x9's. He has significant weight reduction, great suspension and bolt ons. Theres no doubt that it's quick but heres the thing, the course we drive on is a gokart course and it's basically all suuuuper tight turns and you almost never get into second.

I really pushed it hard and it was sooo much fun and holds the turns great but I noticed that even with the Rivals on 15x9's, when powering out of a tight turn the wheels spin. It does accelerate while spinning so I know I'm making good time but now I'm wondering something..

Will the turbo render first gear useless? I'm not sure but I'm thinking staying in second might not work with the turbo in terms of going from 10mph to 30 or so. I have a 6 speed btw and I currently have a uninstalled t25.

If you can't hook without a turbo, a wild guess would be that it won't get better with a turbo.

I vote to find a better auto-x course :)

Edit, my 1st gear in a 5 speed with 220whp involves a lot of spin at WOT with 205 rivals. I'd imagine 225's won't get rid of it 100%.

There are absolutely no other courses :crx:

.. unless the I consider the mountain road a course lol. I live on a relatively countryish island of Hawaii.

Ouch. I wouldn't say 1st will be useless, but rather you'll be forced to get very good at throttle modulation. And you can always run less boost for auto-x.

An autocross course in which you never leave first? wat?

Throttle modulation.. Yeah I guess that's a solution.

Less boost.. Cant go less than stock waste gated 7psi so I don't think this will make a difference.

Heres the track.

I don't your turbo will be very effective in 1st gear only. Just sayin...

https://www.miataturbo.net/attachmen...ine=1427143468

3.6 diff gear and 4psi actuator?

When I would autocross with my car, I would launch in first then switch to second before I was even past the starting line. Then usually I would stay in second for most of the course, unless it was a little larger and I had to goto third.

with a 6 speed and a 3.636 1st gear is good for about the first 15 feet from a standing start it gets me from the stage light to the start light usually. I couldn't imagine using first gear for anything but a standing start. if the car is rolling forward at all id be in second.

now running a Quaife wide with a 4.778. second gear ends up real close to what I had with the 6 speed but and first gear is much closer to second and seems much more useful. I'm wondering yet if it will help my 60ft times at pro solo.

8600 rpm rev limit keeps the use of 3rd down for autocross. my car will spin 275 hoosiers at will in 1st or second between ~4000 and ~7000 rpm.

Gearing & past experiences aside. Will a turbo assist OP in 1st gear runs on said go-kart autox course?

looks slow but Dosn't look like a 1st gear course to me that 350 went to second at the first cone in the slolom didn't it.

Interesting idea..

I did like 10 runs of the same sub 50second course and me staying in first gear and powering out of corners and holding the rev limiter for a couple seconds around some turns put me at one second faster than my 2nd gear runs.

It's impossible for me to hit even the top of 2nd, let alone 3rd even in the one straight away in this course and usually that straight has slalom or you gotta turn mid way.

I'm not sure if the 350 went into 2nd but correct me if I'm wrong but the v6 in that z has a lot of low end grunt. Also, that z now has like 275's all around I believe and it ran a second faster than my best run. From my inquiries, seems like most of the miata guys stay in first of course unless one needs to go into second.

With a small turbo you'll pull 2nd gear fine and only downshift to first here and there.

this course sucks balls.

^

I was hitting 4th on the go-cart tracks I have run on. both Pacific Grand Prix and the one at Grand Junction for the Flyin miata Open house. they didnt have all the extra cones or the non standard track direction turns though.

t25 spools from around 3k no? I'll check my rpms today at 10-30mph.

lol. Well it's the only course we have so I'm not complaining :D

Yeah it would be cool if we had a bigger track like that but oh well, it's country side Big Island of Hawaii. :skid:

If this is the only course you have I would stop modding your miata and just buy a damn kart.

Fun fact: Shifter karts used to dominate many autox circuits, until most sanctioning bodies added rules like "vehicle must have suspension" and other to rule out shifters without saying no shifters.

They still do. They have their own class in SCCA, they're fun to watch, especially when they finally go beyond their ability to catch a slide at 60 mph, which is quite easy.

But seriously, OP's course blows. I'd rather spend my money on a single speed kart, and, you know, just go kart racing. W2W karts that only go 45mph would be way more fun than autoxing that, assuming a club exists to run with.

^^ Agreed. Either run what you have to learn how to drive YOUR car better, upgrade your car to make YOU happy on the roads YOU drive everyday and learn to drive that, or spend your money on a kart and learn the principals of driving fast with the best platform for that specific venue.

I drive with Windy City Miata Club in the suburbs of Chicago and we have a parking lot that we autocross on that is notoriously technical but I spend most of my event in 2nd, sometimes third gear.

Did not know. That's even better.

Yea 1st gear autocross is not so much fun. Steering inputs on a course that requires you to go that slow just get ridiculous and harsh and the wonderful feeling of controlling and dancing with vehicle dynamics and tire slip angles just goes out the window.

MS3 + Boost by Gear + 4 psi wastegate spring

I have >0psi before 2000rpm, 7psi by 3100rpm.

You will not have a difficult time spooling your turbo in 2nd on that course unless you're driving like your sister's friend's dead grandmother.

Does this count as suspension?

https://www.miataturbo.net/attachmen...ine=1427324553

That has to be a drag car.

Whatever it is, I'm fascinated with it.
Love looking at crazy suspension setups.

Looks like it allows for about a quarter inch of travel though? tops

I'd say, but I'm no official.

And as others said, it looks like a drag car..

What happens between 2-3?

I think maybe boost builds...?

It'd probably look a little something like the red line, blue line, or yellow line. Not sure which.

https://www.miataturbo.net/attachmen...ine=1427347325

Yellow line looks like mine.

Please tell me you just drew that.

Here's the thing.

I've seen people who have considerably less resources successfully turbo their car.

I've seen people more clueless than you who successfully turbo their car (read: dropped they car off someplace with a blank check).

But from where you are right now, your combination of cluelessness and lack of resources does not look promising.

You really shouldn't be touching this thing right now. You need to do a lot more reading and learning first.

Then again, you'll likely only destroy this car about as much as I destroyed my Saab Turbo and Merkur (read: both ended up parted out by the next owner).

I use my Galaxy Note tablet for very important diagrams like the one shown above.

Nice, I hoped it was an mt.net original.

Attachment 233455

Side note, I need to get this 7psi IWG sorted out.

how about just build a car and not worry about the autox track.

Yep, well said. I did an autox in a small lot with a BMW club once where I never left 1st gear. The car was too jittery and jumpy to have fun navigating around cones at a max of 30-35 mph. It's just the wrong tool for the job.

:laugh: lost it on the yellow line

the last time i saw someone do an autox in 1st they blew the motor.

apparently s2000 drivers never heard of momentum.

You mean the gas pedal isn't an on/off switch?

My motor has about 20 more hours on it at WOT since that bimmer event, so I guess I did OK.

Yes, you are right. And thats why I don't really care about what class I'm put in either but I don't know, i definitely didn't want to be slower or loose the usefulness of first gear. If the second gear spool does not work out on my track, second will be a boring gear. Luckily, even if I don't get traction in first, it will be:skid:

But maybe 2nd will work out :D

I bet 2nd will be a lot of fun on the street or at the track with a GT2554.

What gear is that in?… Um if that makes a difference. :D and what turbo?

I have a t25 though. :/

Man, turbo with second gear might actually be faster AND perhaps less wear and tear because I won't be revving it up to 7k. :D Might just be perfect :bigtu:

Dammiy ryu. Stop changing things. I hereby banish you to at least 15 minutes of research before each post.

T25=2554

Oh, I tawt gt was the BB :/

GT is the BB version, but they're the same size turbo.

Okay so yup I know that but the BB spools at least couple hundred Rpms faster no?

Not really on a turbo this size. Yes it'll spool a little quicker but a 2554 journal bearing is going to spool lightning quick on a VVT 1.8. You seriously have nothing to worry about.