Performance Shock, Inc. Ohlins TTX

[RYU]

This is the lowest I can currently go in the front now:
View attachment 156225

Mac, help me understand something cuz I have small brain syndrome. Wasn't one of the goals on custom measured shock bodies to achieve your desired ride height? Isn't the adjustable bottom bracket design there for fine tweaking of the ride height? Now that you'll be exploring shorter springs would the internal piston position still be at optimal placement? I might be overthinking this...

Dude, the 02 wheels look amazing on your car. That's not painted Champ White, is it? Looks more GPW in the pics

 

[jwmelvin]

The internal piston position should define the ride height, right? So shorter springs are just to allow him to get to the desired piston position. I haven’t had any issues without helper/tender springs on my track car but I can understand why one might want them.

 

[Mac Attack]

Mac, help me understand something cuz I have small brain syndrome. Wasn't one of the goals on custom measured shock bodies to achieve your desired ride height? Isn't the adjustable bottom bracket design there for fine tweaking of the ride height? Now that you'll be exploring shorter springs would the internal piston position still be at optimal placement? I might be overthinking this...

Dude, the 02 wheels look amazing on your car. That's not painted Champ White, is it? Looks more GPW in the pics

These don't have an adjustable bottom bracket for ride height like popular Asian products do. Only the spring perch is adjustable for ride height, and we know that up front that the lowest position it can go is where it hits the upper control arm (unless you offset the top mount like you mentioned previously). I didn't want to offset the top mount because I would loose compression travel, which is very important when you're sticking the lift cups up top.

And yes, these shock bodies and pistons were custom designed to maximize suspension travel. Even with these thick lift cups I have about 110mm of travel up front, which is fantastic. Fortunately, that also corresponded to a nominal 7" long spring with about a 2" block height fully compressed so it all worked out. We knew the lowest position up front was going to be close to the upper a-arm, but again, I was trying to keep from spending another ~$400 going to a tender/helper setup. Well, that didn't quite work out.

The TTX dampening should be consistent over the full range of travel, so piston position shouldn't matter. That's unlike a spool valve design like Multimatic's where dampening is dependent upon piston position.

Thanks for the feedback on the wheels. No fancy painting or powdercoating - It's just Duplicolor rubber white coating like Plastidip to (hopefully) provide some protection for the flawless OEM finish underneath.

 

[RYU]

Ah! TTX aren't like the DFVs with the adjustable brackets (at least for the S2K they were). Gotcha. Now that makes sense.

 

[Mac Attack]

Trying to get a few driving days in before it gets too cold:

View attachment 156289

 

[Mac Attack]

Finally found some time to swap out the springs.

I had swapped the fronts out before I remembered I wanted to weigh these things sans lift cups and top hats for the unsprung weight.

The rear setup you see below weighs an amazingly-low 2 lbs, 4 oz. The fronts felt about the same if not lighter.

View attachment 157010

Here's the fronts back in place with the helper spring. While it is technically a helper spring that will be fully compressed under the corner static weight, it does have a decent 150 lb/in spring rate unlike the traditional weaker helpers you see in other NSX applications. It's almost like a dual-rate tender setup, but only over big bumps.

View attachment 157016

I'm really happy with this setup. The ride over potholes in my area is smoother than my daily driver!

And, since PSi set up Kips DA NSX racecar with this TTX damper, I'm really looking forward to going to the track this Spring!

 

[RYU]

What rates did you end up with?

 

[Mac Attack]

What rates did you end up with?

450 lb/in front, and 350 lb/in rear.

 

[RYU]

450 lb/in front, and 350 lb/in rear.

Nice!

I've found my sweet spot.

~500 lb/in = 9 kg/mm Front
450 lb/in = 8 kg/mm Rear

 

[Worm]

Can't see your attachment 155661

 

[Mac Attack]

Yeah, we're limited by total attachment upload size per account. I don't use any other file-sharing service, so I tend to go back and delete old pics that are outdated or unnecessary.

What are you interested in seeing? The air tank, layout under the front hood?

 

[Worm]

Yes, and how the compressor is mounted to reduce the sound level. I have the iLift compressor and tank mounted inside the rear right quarter panel and the sound and to some the vibration when the compressor starts pumping is quite evident. Thanks

 

[Mac Attack]

A lot of compressor noise is from the intake. The typical cheap intake filter is small and made out of plastic with porous foam to "filter." In my compressor location down low and exposed to a lot of contaminants I wanted to provide better filtration. So I used a rubber coolant hose with an ID about 5x the inlet area of the OEM compressor filter, and used a cheap oil breather filter mounted up near the top of the compartment. It should provide cleaner air for the compressor to increase pump life, there is less air intake restriction (I know there's no restriction because the non-vacuum-rated hose is not collapsing on itself), and probably the best benefit is that is really quiets down the compressor noise.

I don't know how the iLift compressor is mounted, but you can see how the rubber/spring isolation kits are used if you click on the link I had in post 13. The Viair models have different mount spacing depending on the model number. You buy the isolation dampers according to the Viair model you have. I have a feeling Steve uses a "better" compressor for his ilift that lasts longer and is more expensive, but I like my Viair compressor and I can get one delivered to my home the very next day instead of waiting for one to come over from Germany.

You can't see my compressor and the rubber mounts very well since they're mounted down low next to my lithium battery, but here's a pic showing everything. I was testing if my setup would work OK with one or two tanks. Now that I know the single tanks is OK, I need to find a better place to mount it that will work with the radiator ducting.

Note the SMC air dryer off the compressor. I also use DOT 1/4" line to the tank and other places. Also visible at the front of the compressor is an aluminum mount to support the flex hose due to its length, but I don't think that's really necessary.

View attachment 157099

 

[jwmelvin]

Note the SMC air dryer off the compressor.

Does it collect much water?

 

[Mac Attack]

I haven't made any accurate measurements since it varies with usage and humidity, but it does collect moisture and it keeps my tank dry! There's a little Schrader valve at the bottom so it makes it easy to empty.

 

[Worm]

Thank! Very tidy looking set-up

 

[Mac Attack]

No problem, hope that helps.

I would like to find my calibrated SPL instrument so I can measure how loud the compressor actually is. Let me put it this way, it's about as loud as the floating midplate whir on my old SOS/RPS twin carbon clutch when disengaged. It's WAY quieter than the cowbell/metallic noise from the OSG clutch midplate rattle, or the old ABS pump shrieking noise!

 

[Mac Attack]

Final Ride Height:
View attachment 157172


Lifted:
View attachment 157173

Now I can finish the aero and not worry about it being scraped off. The side sills for the rear diffuser sit lower than the Wings West rear spats, and the whole thing extends half an inch past the center of the rear bumper. The new front lip sits at the same height as the '97+ lip, but the splitter extends two inches.

The car rides much smoother than the MDX sitting behind it. There's no squeaks, rattles, or noises, and it will be ready for the track next Spring....

Thanks Bruce and Brandon at PSi!

 

[Mac Attack]

Took a trip out west recently and stopped by Sonoma Raceway. Bruce, the owner of PSi, was happy to take a few minutes of his busy day to show my family and I around. I just have to say that I've been extremely impressed with PSi's knowledge and professionalism.

They obviously know how to satisfy the NSX customer range of requirements. From Kip's Driving Ambition championship racecar to mine with a smooth, compliant street ride.

 

[baxtersit]

Where in western PA are you located as I'm from Cleveland and have a 97? Would love to see how the Ohlins feel with street settings. Thanks. g

 

[Mac Attack]

Where in western PA are you located as I'm from Cleveland and have a 97? Would love to see how the Ohlins feel with street settings. Thanks. g

Welcome to NSX Prime! I tried to send you a PM but an error message said you have it turned off or your account is too new. I think the magic number for PM capability is 10 posts, so please make a few more!

A short drive this evening:
View attachment 162508

 

[baxtersit]

I have the magical 10 posts in so lets see if you can reach me now. Thanks

 

[Mac Attack]

PM sent.

 

[Mac Attack]

[MENTION=30095]JohnWayne[/MENTION]

This is a pretty sweet setup and by far the nicest I've ever driven/riden in for the NSX, and that includes the KW offerings, JRZ offerings, OEM NSX offerings, and a few custom Penske setups for the track.

It's a bit hard to see the custom inverted clevis mount so the spherical bearing is oriented correctly and not like your more typical cheaper designs. There was quite a bit of iteration and measuring as you can imagine to get the maximum stroke and droop for the desired ride height taking into consideration the spacing taken up with the lift cylinder. I give kudos to PSi, the ones who also set up the award-winning TTX suspension on Kip Olsons NSX. Also, I'm a few time zones away from them so we had to do some occasional shipping of test specimens for measurement.

The lift cylinder is a bit too long considering the motion ratio for the front, but I had purchased it about 10 years ago and wasn't about to do custom machining just to lose a half pound. A shorter design like the other commercially-available ones wouldn't have given me the full lift I wanted either (as you can see below).



The proof is in the droop shown in these two pics comparing normal ride height and fully lifted. Because of all this droop plus another (I forget) generous allowance for compression travel, I have a great-riding suspension. I later added some lower-body aero so I need the lift front and rear just to make it in/out of my garage.

 

[Mac Attack]

This fall will be four years on the dampers and front/rear lift pistons. Will probably ship them to PSi for a rebuild. They've worked flawlessly and PSi obviously knows how to set up the NSX (they did these TTX's on Kip's car too). Give them a call - They've got the specs!