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Si's Helical LSD - Not competent on Track!

CanadiaegeanBlue

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I've started taking my Si to the track, having done 3 sessions at the local circuit so far this season, Toronto Motorsports Park (TMP). This track being more technical rather than flowy has brought out an an interesting flaw of the Si that was pinpointed by Dave Pratte from the YouTube channel, Speed Academy. If any of you are Speed Academy fans, Dave and Peter are masters of TMP, building track capable street cars and reviewing all sorts of press cars, fans' rides etc.

Watch the video in full for not only his impressions on my Si, but the Si vs. Type R debate, and more importantly hear how the Si diff is not letting us put the power down and causing understeer.


Dave obviously being more skilled than I am could tell within the first lap that the Si's Helical LSD was locking and unlocking in turns, and not letting him put down the power coming out of turns. I also felt the same on my last two outings in September as I started pushing the car more - in the first outing I didn't have a sway bar so I thought maybe its because the rear is dragging, or maybe it's the tires, but in the second outing after the Whiteline 22mm RSB I still felt the car hesitating so I was lost for an answer other than maybe it's the tires still.

Dave mentioned that the Continental ExtremeContact Sport is a competent tire than can handle light track duty, and he is certain that having a clutch-type diff would eliminate this issue, and free up as much as 2-3 seconds per lap which is huge at this track.

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So what's the solution?

An article by Grassroots Motorsports posted on Monday states that Honda will sell you a turn-key Si racecar that comes with a Diff developed by HPD and Cusco. Historically HPD parts haven't been available for consumers unless you're in on the racing program. https://grassrootsmotorsports.com/articles/factory-firecracker-honda-civic-si-race-car/

I've sent an email to TeamM Factory, they make LSD's for the L15B non-Si vehicles, to see if they're doing anything for the Si. Awaiting response. http://www.teammfactory.com

Does anyone have contacts or aware of any other company that is making or would be interested in developing solutions for the Si? Wavetrac, Quaife, OS Giken etc.



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CanadiaegeanBlue

CanadiaegeanBlue

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@[email protected] Hey Chief, any info?

Also, I got your High Flow Grille on my Si after seeing temps go past 220f at my previous outing within 3 laps with the Si stock grille. This time as I also mentioned in the video that the grille made a big difference as after multiple laps with Dave pushing the car I read out 208f. Pro Civic has my endorsement :thumbsup: Pics you can find on my build thread; link in Sig.
 
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CanadiaegeanBlue

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burglar

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Weird, the Si LSD works fantastically on a stock car. The Type R also uses a helical-style LSD, but unsure if the torque biasing ratio is different. Wonder if you have some issue with droop travel or maybe your mods exceed the lockup capability of the OE LSD. Are you on the OE front swaybar? If you have insufficient locking, you should just boil the inside tire on exits. That shouldn't cause understeer, though, it should just make it harder to put power down.

It appears in the video as if you use the full pedal dance to disable all the nannies, is this correct?
 
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I asked Dave if he encountered this in the stock Si, and he said yes although not as dramatic which is likely due to a stock Si pushing a lot less torque. I am on the OE front sway bar and thoughts are to change that when I am doing the clutch, and that would be the best time to change out the differential too if one becomes available.

I did the full pedal dance for Dave before he jumped into the Driver's seat. I've tried myself with the only VSA off, and full pedal dance with both times yielding the same fight from the LSD. Power is plenty to light the tires up the tires but the diff was interfering before that.

--

I'll mention my modifications here for reference. To be dyno'd but from my tech who has a similar setup plus dyno at his shop the car should be at 260whp and 310wtq.

Engine: Hondata +9, Mishimoto Intake, Mishimoto Intercooler Kit w/Piping, Mishimoto Catch Can, 27Won Engine Mount, 27won Catted DP + FP, Magnaflow Catback
Transmission: Acuity Short Shifter, Acuity Cable Bushings, Acuity Pedal Spacer Bracket, Acuity Shift Boot Collar, Mishimoto Carbon Fiber Shift Knob
Chassis + Suspension: K-Tuned K1 Street Coilovers, K-Tuned Rear Camber Kit, Ultra Racing Strut Bar, Ultra Racing Trunk Brace, Type R Subframe Brace, Whiteline 22mm RSB set to softer setting
Wheels and Tires: Konig Freeform 18x8.5 ET35, Continental ExtremeContact Sport 245/35ZR18, Muteki Steel Lug Nuts
Brakes: Front - Brembo 4-Piston Calipers from Hyundai Genesis Coupe, mated to Nissan Rogue with 3rd row seat Rotors (320x28mm), Stoptech Sport 309.10010 Pads, Dot4 Fluid, and Goodridge SS Lines. Rear - OE Rotors + Pads, Rear SS Lines
 

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I'll mention my modifications here for reference. To be dyno'd but from my tech who has a similar setup plus dyno at his shop the car should be at 260whp and 310wtq.
260? Damn those are some good numbers. Who is your tech/tuner? I'm around your local area and would be interested.
 

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Isn't the title a bit of hyperbole?

The stock LSD works well enough for track weekends and the new SCCA time trial series. At stock, or near stock horsepower levels, it will get the job done unless you are trying to run at the pointy end of things.

Clutch-type LSDs are better at putting down power, but require more maintenance and tuning to get right. I had a MFactory LSD in my 1996 Integra that I used for HPDE and it was amazing, but I also had to tear it down each year.

I've run 14 20-minute sessions in my SI and find the LSD to be very helpful at pulling the cars through turns and providing traction on wet days. I normally run a 300+ wear tire, the Continental Extreme Contact Sports, but have had similar experiences with a few hot laps on RE71Rs. A slightly bigger FSB will also help these cars pull through corners, something I would highly recommend.

From what I've seen, the mechanicals of the Type R and SI LSDs are fairly similar. The Type R's front suspension is doing some amazing things to keep the front wheels planted and moving in the right direction. Combined with a slightly bigger front-sway bar, it doesn't surprise me that the Type R feels better on a track.
 
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Isn't the title a bit of hyperbole?

The stock LSD works well enough for track weekends and the new SCCA time trial series. At stock, or near stock horsepower levels, it will get the job done unless you are trying to run at the pointy end of things.

Clutch-type LSDs are better at putting down power, but require more maintenance and tuning to get right. I had a MFactory LSD in my 1996 Integra that I used for HPDE and it was amazing, but I also had to tear it down each year.

I've run 14 20-minute sessions in my SI and find the LSD to be very helpful at pulling the cars through turns and providing traction on wet days. I normally run a 300+ wear tire, the Continental Extreme Contact Sports, but have had similar experiences with a few hot laps on RE71Rs. A slightly bigger FSB will also help these cars pull through corners, something I would highly recommend.

From what I've seen, the mechanicals of the Type R and SI LSDs are fairly similar. The Type R's front suspension is doing some amazing things to keep the front wheels planted and moving in the right direction. Combined with a slightly bigger front-sway bar, it doesn't surprise me that the Type R feels better on a track.
Still looking into this topic guys, I've been busy with a couple of other projects off the forum. It could be that I need a Front Sway Bar to accompany the thicker Whiteline RSB I have already. However, with coilovers and camber plates I've dialed in -2 Camber front, so my Continental ECS 245/35ZR18 really do stay as flat as they can be. I'm hoping to be able to fit 17x9's over my Brembo BBK setup with 255/40R17 Hankook RS4 or similar tires next season.
YT_Day_2019-19.jpg

YT_Day_2019-18.jpg
 

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Isn't the title a bit of hyperbole?
1st rule of the modern internet, use extreme hyperbole. Get them clickz yo. Promote your brand. Views, likes, and followers are everything.

Again, check both your compression and droop travel in the front with those coilovers. If you're on the bumpstops in compression, or you're running out of droop on the inside front in the corner, it'll cause you all sorts of troubles both with general handling and also with a biasing type diff.

I'm still voting for user error on the setup as most likely root cause.
 

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1st rule of the modern internet, use extreme hyperbole. Get them clickz yo. Promote your brand. Views, likes, and followers are everything.

Again, check both your compression and droop travel in the front with those coilovers. If you're on the bumpstops in compression, or you're running out of droop on the inside front in the corner, it'll cause you all sorts of troubles both with general handling and also with a biasing type diff.

I'm still voting for user error on the setup as most likely root cause.
I'm agreeing. It sounds like the user isn't running a FSB, which with a bigger RSB, would really reduce traction up front.

Outside of autocross, I don't really see the need for people to run massive RSB on these cars. They do have significant mechanical grip in the rear, but I find it more predictable to add a bit of rear toe out if rotation is an issue.
 

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I'm agreeing. It sounds like the user isn't running a FSB, which with a bigger RSB, would really reduce traction up front.

Outside of autocross, I don't really see the need for people to run massive RSB on these cars. They do have significant mechanical grip in the rear, but I find it more predictable to add a bit of rear toe out if rotation is an issue.
Just curious... Is upgrading to a bigger FSB specific to the OP because of how much power he is running? where as stock power would be okay with just a RSB? I only ask because due to regulations in GS most everyone i see changes the Rear vs the Front with good results. May have answered my own Q but im guessing this is a trade off you have to make to qualify for GS... where as if you could, you'd install the bigger FSB as well for optimal performance?
 
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The plan for this year is to raise the ride height a little, and try different settings on the coilovers - stiff front, soft rear, and then vice versa. The reason I didn't get a FSB is that from my understanding it can have a bit of push into understeer, which I don't want.

My anti-lift kit from Whiteline has been delivered so that will be going in at the same time as the CTR clutch retrofit. The ALK should help with traction and turning grip under power. I will be installing a Front Power Brace by Ultra Racing however.
 

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The plan for this year is to raise the ride height a little, and try different settings on the coilovers - stiff front, soft rear, and then vice versa. The reason I didn't get a FSB is that from my understanding it can have a bit of push into understeer, which I don't want.

My anti-lift kit from Whiteline has been delivered so that will be going in at the same time as the CTR clutch retrofit. The ALK should help with traction and turning grip under power. I will be installing a Front Power Brace by Ultra Racing however.
Idk what your current alignment setup is but based on your prior build posts its probably worth a shot to dial that in.

Lately I've become borderline obsessed with the ins and out of FF alignment tuning (still take this with a grain of salt tho lol). Everything i keep reading seems to be pointing in the direction of more camber in the front than rear in my case.
Obviously this needs to suit your driving style as well. Im still gathering info in regards to that topic but anyways... Little to no toe up front.. more track/autocross orientated seems to be -0.16° to -0.32°. Rear toe is some where between 0.02 and 0.06 (Again dependent on your needs, skill set and driving style).

Although we do have to keep all your other mods in mind to tune the alignment properly.
"The following will produce a (more) oversteering car:
  • Running front camber more negative than rear camber.
  • Running rear toe more out/negative.
  • Running front toe more out/negative."
All info was from these links. So if there is something i shouldnt be listing to by all means... LET ME KNOW haha
http://www.redshiftmotorsports.com/RedShift06CivicTech.htm
http://racetrackdriving.com/car-setup/track-alignment/

Hopefully some of these guys from the GS thread and add their .02 tho! they've been battle tested so their word is bond lolol
The more i dig into this topic, the more i am starting to regret my tuning path lol Glad i stumbled across some good posts in the GS thread or else id just be another civic thats all bark and no bite lol
Happy Tuning!:drive:
 
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CanadiaegeanBlue

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Idk what your current alignment setup is but based on your prior build posts its probably worth a shot to dial that in.

Lately I've become borderline obsessed with the ins and out of FF alignment tuning (still take this with a grain of salt tho lol). Everything i keep reading seems to be pointing in the direction of more camber in the front than rear in my case.
Obviously this needs to suit your driving style as well. Im still gathering info in regards to that topic but anyways... Little to no toe up front.. more track/autocross orientated seems to be -0.16° to -0.32°. Rear toe is some where between 0.02 and 0.06 (Again dependent on your needs, skill set and driving style).

Although we do have to keep all your other mods in mind to tune the alignment properly.
"The following will produce a (more) oversteering car:
  • Running front camber more negative than rear camber.
  • Running rear toe more out/negative.
  • Running front toe more out/negative."
All info was from these links. So if there is something i shouldnt be listing to by all means... LET ME KNOW haha
http://www.redshiftmotorsports.com/RedShift06CivicTech.htm
http://racetrackdriving.com/car-setup/track-alignment/

Hopefully some of these guys from the GS thread and add their .02 tho! they've been battle tested so their word is bond lolol
The more i dig into this topic, the more i am starting to regret my tuning path lol Glad i stumbled across some good posts in the GS thread or else id just be another civic thats all bark and no bite lol
Happy Tuning!:drive:
Top man, this is excellent information and I will dig more into it! My tech is awesome at alignments, and the plan is to corner balance the car this after all is installed but I also wanted to seek input from someone who is well versed in FF suspension geometry to really help dial the car in. Front Camber was -2, and Rear -1.5. Toe was 0, and Caster I cannot recall at the moment.

Thanks for all the help guys! I'm not trying to set any records or do crazy time attack, just love showcasing the platform's capabilities :)
 

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seek input from someone who is well versed in FF suspension geometry to really help dial the car in.
Let me know what your guy says cause im really curious as well. I'll also be looking for it in your build thread which im sure you'll post in there as well lol
 

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