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Old 03-21-2021, 06:54 PM   #1
PlayersLtd
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Default Will I regret a sequential gearbox?

Hey all,

I searched around and didn't see an appropriate thread so I'm opening a new one.

I'm embarking on a reasonably aggressive race build on my '09 STi hatch. Key features are a Roger Clark short block with dry sump, MOTEC m150 ECU and a PPG 6 speed sequential gearbox, or maybe a sequential.... That's why I'm here.

I've done a lot of the research on pros and cons but I'd like to hear from somebody who has a sequential set up with straight cut gears in their street/track car to tell me how they feel about it when city driving.

My car is being race built but the reality is it will remain a weekend boot around and will be on the track for 1 out of every 10-20 hours of daily driving, for now anyway. I live in a town that due to its geography isn't full of great driving routes and opportunities to stretch my cars legs so when I say city driving I mean city driving, minus the sitting in traffic element. Not many spirited driving opportunities unless I really get outside the city limits.

So, the question is- will I regret a sequential gearbox and straight cut gears? I'm prepared for the common drawbacks but I'd like to hear from someone who is driving a sequential in the city a fair amount and can tell me if its annoying or not.

There are a few angles here: 1/ Missing out on manually shifting an H pattern and rev matching, heel and toeing etc... 2 / The lack of a neutral position to coast in when cruising to a stop light etc... and the inconvenience of having to descend through all the gears when slowing 3 / The sound of the straight cut gears for city driving, albeit I'm told the PPG is not that bad in this regard.

Was anyone on the fence about a sequential like this and turned out loving (or hating) it??? Sequential gearbox owners please weigh in.

Thanks for any input.
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Old 03-22-2021, 07:51 AM   #2
PyroguyFTW
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I don't personally have straight cut gears on my WRX, but I used to have them in a t56, and they made insane amounts of noise. I personally loved it, but I was also 19, and had other ways around for the weekdays like yourself. If PPG found a way to reduce gear whine with them, and still retain all the strength and reliability, I would say go for it.

As for the sequential, I have nearly zero experience with them, so take my opinion with a grain of salt. It might be a little much in a lot of stop and go, especially if you have close ratios. If you're banging through first to third(or heaven forbid fourth) just to make it between stoplights, you're gonna regret that in a horrible way.

At this point, I would try to decide whether you want a race car for the street, or a street car you can race. My initial thought is that if you're questioning whether or not you'll regret a sequential, chances are you will. Again, my experience with both is limited, but sometimes you need an outside viewpoint that hasn't been soaking in the research as you've been.

One parting note, if you have to drive through areas that are gonna make it a chore to take it for a spin, you've gotta decide which setup will not leave you feeling frustrated by the time you find some open road. I know with my t56, it was hell getting stuck behind someone who was going 10mph in a residential. It was almost too obnoxious in first, and too slow for the idle in second. It would ruin my drive quicker than anything getting stuck behind someone with no desire to even go the speed limit. If this car is going to see much road use, take some notes of how fast you're going on the routes you'd normally take, and use some gearing calculators to find out how often you'd be shifting it. Only you can decide what's right for your tastes.
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Old 03-22-2021, 08:21 AM   #3
snow_bound26
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In my experience, and as noted by the previous post, decide if you want a true track/race car or if you're looking for a street car that you can take to the track. If you are driving on the street fairly often (weekends for instance), you most likely will hate a sequential trans as will your neighbors. If you decide on a sequential, then you'll also need to accept the additional cost of rebuilds and extra maintenance over an OEM trans. Generally people that go this route trailer their car to the track and it's about the last thing they do for their race car. A good sequential trans is serious money and for someone who is truly chasing tenths or even hundredths to win.

Going with an 04/05 USDM 6 speed or a JDM 6 speed will give you good close ratio gearing for the track while not making you insane while driving on the street. A rebuilt 5 speed with PPG gears is another great option. Just ask Unibomber for his thoughts on them. Straight cut will whine a lot more. You may enjoy it. You may not. Everyone's acceptable level of NVH is different. I'd recommend an option with synchros unless you're really really really good at timing your shifts.

Rally cars and Ken Block make sequential look cool, banging through the gears, hearing the engine sound crazy at high rpm, but they have the budget for it and can rebuild them quite frequently. The rest of us mere mortals are better served with an OEM style gear box and if budget allows, some friggin strong gears if we truly spend a lot of time at the track with a high hp/tq car. Go on YouTube and check out Gears and Gasoline's time attack series videos. You'll see that the highest level competitors still don't have sequentials.
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Old 03-22-2021, 10:28 AM   #4
KillerBMotorsport
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Decide race or street.

Sequentials take a lot of time to dial-in for 'everyday' driving that isn't abusive. On track, who cares if the shifts are neck snapping; you're fully harnessed (with a halo if you're smart), but on the street it will get tiring fast. Heck, I even hated driving a harness on the street so much that I put the OEM 3 point back in and had both setups installed at the same time. The mobility loss from a harness alone in street driving sucks.

Like any racecar, sequantials require regular service intervals. If you're not chasing down 10ths around a road coarse then you're spending a ton of money and time for what benefit?

With the trans, the common thing to do is add straight cut gears in the lower 4, and helicals on 5th and 6th, or maybe just 6th. This will let you sound cool to your buds, but not cause you to want to kick puppies after a 30 minute drive down the highway.

One thing you've not mentioned is what fuel or power target? Do you need a built trans? The drag guys often carry bone yard spares as that's the cheap and easy path to keeping things moving. The other thing to consider is that even a built trans doesn't offer much more protection than stock. You can find many examples of stock trans hold more than some that are 'built'. Speaking of which, most sequentials are rated for not nearly as much power as you'd expect. Last I looked (and it has been a few years so maybe this has improved) the most durable one out there for less than $25K was only good for ~500ft/lbs.
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Old 03-22-2021, 10:54 AM   #5
PlayersLtd
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Thank you all very much, sound advice.

KillerB- I am getting the RCM700 and will be running pump gas with water meth kit (50/50, Aquamist, currently installed on OEM long block). I will tune to + - 500lbs/ft, below what my set up should be able to handle.

You are right about the limits of even a built trans. PPG advertises theirs as good for up to 650 (or 700?) whp whereas you hear a lot of people talk like you can drive 800 + hp through them (along with relative tq numbers).

I'm building a bit of a fantasy car (by my standards anyway...) and want to pull out all the stops and graduate it slowly to a full time track car as I get more seat time. The reality is I have a young family which means limited time, the local track is closing, there's a local track day 'resort' that is overpriced and other than that it's a six hour trip including a ferry to get to the nearest circuit.

Probably not hard to deduce which way I should lean with the track or street decision...
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Old 03-22-2021, 02:50 PM   #6
snow_bound26
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Out of curiosity, what track near you is closing? Hoping it's not a track in the northeast.
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Old 03-22-2021, 09:21 PM   #7
PlayersLtd
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Quote:
Originally Posted by snow_bound26 View Post
Out of curiosity, what track near you is closing? Hoping it's not a track in the northeast.
Western Speedway in Victoria, BC. A 1/2 mile oval that is only good for AutoX in terms of what I would be looking for out of my Subaru but we also drift and I wanted to get into late models so it's a bit of a shame.

Its a real throwback type track and its right in town so the fan and driving experience is pretty good. The land sold and it's slated for redevelopment.

It leaves me only with Vancouver Island Motorsports Park which is a brand new world class facility but only built (and zoned) for track day type events, no real racing, no time attack.

So i'll be running this car at events at Mission Speedway, Area 27 and perhaps in the Lucky Dog Racing League. All to be determined based on how much time (and money) I can devote to the hobby.
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Old 04-01-2021, 11:37 PM   #8
VeteranNoob
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I've also been researching going sequential in my daily.

First, I've gathered that - at least with PPG - once tuned properly for automatic downshift blips, etc. the ride is actually super smooth. To my understanding, the issues are:
- Straight cut whine
- Maintenance
Apparently the STI gearbox's limited space is the restriction resulting in there not being a helical sequential for it- PPG makes helical sequentials for GTRs and Corvettes.

I actually ran into the guy who owns the car showcased
and got some valuable input.

I asked for him to compare various annoying car noises in order to gauge how bad straight cuts and dog engagement are in particular, and he had this to say:

"
10/10 Annoying on a car is an aggressive clutch. Until you've driven a twin disc, or > you don't really understand
9/10 is a car with all the sound deadening removed
8/10 is a straight cut gears/straight cut dog gears (noise only)
7/10 is ****ty driver ergos (Dodge Promaster/Fiat Ducato And ford work vans/trucks)
6/10 is a welded diff
5/10 is no radio
"

By this point - along with others' input - I was pretty much convinced straight cuts would be too much to daily. After all, I want to be able to drive others and not have them hate it- I don't drive enough (no commute), so I need to retain my "I'll drive us!" position amongst everyone in my life
But plan B was developing in my mind...

Enter the CAE Ultra Shifter.
It's a short shifter, it's high up near the wheel, and - critically - it self-centers laterally regardless of engaged gear- meaning 2nd->3rd, 3rd->4th, 5th->4th, and 4th->3rd are all just as simple and easy as with a sequential- straight forward and back (and idk about you, but eliminating the two major money-shift risks is big for me).
This, paired with dog-engaged helical gears, and I may just be able to please my inner child who needs to daily a rally car.
[Disclaimer: Some videos show this shifter not self-centering; I'm unsure if this is due to incorrect installation, or limitations related to different gearboxes, but I know for a fact it can self-center on the
, which applies to me]
This route should also save ~$10k, which is...pretty nice. Lol.

Back to that guy with the sequential daily- when asked to elaborate on the actual dog engagement noise, he didn't even rate it on the scale and said "the clunking is whatever once you get used to it".

That means for plan B to work [for me], there are only two questions remaining:
  1. Is daily-driving dog engagement within reason in terms of wear/service? I'm hoping this is a 'yes' especially for me and my modest power goals (already pretty happy at 300HP), but I'm not sure- contacting PPG and others for input (I want to be able to shift without the clutch sometimes, but I'd still be using the clutch 99% of the time)
  2. Can I get helical gears with dog engagement? The answer to this seems to be 'yes' according to this link (if space is saved keeping 5th and 6th synchro, maybe?), but I've yet to speak with a real person about it and that's the only place I've found online- everywhere else listing dog engagement for the Subaru shows straight cut only (and PPG have told me they won't do a custom solution) minus this, which I've not discerned if will work with my 2019 WRX

Yes, I have a WRX and am seriously planning my immanent swap to sequential / dog engagement- it's a better platform for someone who doesn't want to engine swap- fight me :P
On that note, what I'll probably do personally is swap to the STI transmission, install the CAE, and see if my inner child is satisfied by that before replacing my gears, if I find that really is an option.

This is all assuming I don't leave my current life behind and start anew in a country that sells the GR Yaris... ... ...

Quote:
Originally Posted by KillerBMotorsport View Post
If you're not chasing down 10ths around a road coarse then you're spending a ton of money and time for what benefit?
Oh you silly goose- the benefit is RACECAR!!! If I wanted to shave time off my laps, I'd get better at racing! And that's not even an option for me...because I don't race!

But hey, maybe you can help educate on my "plan B" above, using dog engagement on a daily?
Firs off, I understand how they work; I know I'd need to relearn how to drive.
I do plan to take my car to some casual rallycross, but it really would be as casual as it can get, and very infrequent (I already know what beater car I'm probably going to buy if I do decide to commit a lot of time to the sport)- I'm also not pushing a lot of power, and don't feel all that compelled to push much further.
I'm basically just looking for some variation of "If you use the clutch like normal and shift properly (more abruptly/purposefully), dogs will last just as long as synchros under 400HP; up-shifting without the clutch is fine every once in a while"- except whatever the truth

Last edited by VeteranNoob; 04-02-2021 at 01:56 AM.
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