Suspension mod question Options

[Kislik]

stock car has the suspension setting . normal, comfort and Race. when I change to for example KW or Cobb this will not work.. Am i right?

so when i want to keep this option, i can only change the springs to drop the car..

right?

[MindlessOath]

stock car has the suspension setting . normal, comfort and Race. when I change to for example KW or Cobb this will not work.. Am i right?

so when i want to keep this option, i can only change the springs to drop the car..

right?

Changing to a full coil over replacement will void those settings. Using a conversion kit like the cobb version will not void those settings.

[Sharif@Forged]

Although you loose the in cabin adjustment, the vast improvement by moving to an upgraded coilover system like KW, JRZ, or TEIN, will vastly outweigh the loss of this function. It will still light up red, if that is a concern.

[Sharif@Forged]

Double post...sorry.

This post has been edited by Sharif@Forged: Feb 15 2009, 05:21 PM

[First]

Sharif how would you compare and rate between coilover conversions likes those of Cobbs, Amuse and Top Secret with those of actual full coilover systems such as HKS hipermax, Sachs, Zeal, Tein and etc?


I just changed over to Top Secret sleeve conversion type and the rear suspensions clunks a bit on the top part, dont know if thats normal or installation error. Gonna go back up to troubleshoot it again. As the stock suspension uses rubber mounts while the aftermarket ones uses steel mounts, does it means aftermarket ones is going to make a fair big of clunking or knocking sound?

[ggolamco]

I remember seeing a post which discussed using the stock switches with the in-cabin module from TEIN for making adjustments to their coilover system. Any updates on that?

Although you loose the in cabin adjustment, the vast improvement by moving to an upgraded coilover system like KW, JRZ, or TEIN, will vastly outweigh the loss of this function. It will still light up red, if that is a concern.

[MindlessOath]

Tein has there own adjustment controls. They are different but they are in cabin and you can mount them wherever u can.

[descartesfool]

For the street, simplest mod to drop the car an keep the OEM damper adjustments is to simply change the springs for Eibach ones. Front drops about 0.8" and rear drops about 0.5" with a very small increase (hardly noticeable) in spring rate. Since you are not changing any damper shaft bushings, there will be no increase in noise or clunking. The drop and just the drop is the raison d'etre of the Eibach spring set for the GT-R.

For the track, things are different. I have always found that anything that is really good for the track is not very good for the street. The stiffer you make the suspension, the better it handles on track, and the more uncomfortable and noisy it gets on the street. You can't really stiffen the springs without stiffening the dampers, as the two must match. And stiff dampers are not comfortable on the street. The GT-R is already pretty stiff in R mode. I have two cars I use on track, one with extremely stiff springs, dampers and full spherical bearing pivot point setup. It is the last thing you want to drive on the street, unless things are glass smooth. The other one has only a very stiff spring setup with race dampers and spherical bearing top hats, and while usable on the street, it kind of takes a lot of the pleasure out of going from A to B. But cars shine on track. Stiff suspensions are not for everyone.

If I was going to change springs on the GT-R, I would start with the Nismo GT-R package rates or something close to it.

[Kislik]

I plan to use my GTR on street and track. My M3 was lowered with TCK coilovers, with stiffer springs and it was very low. Great handling but almost unusefull for street. Too low, too stiff. So this I don't want to do with the GTR. Just a little drop for the look and center of gravity.

So eibach is ok? Cheap, not so stiff and easy to install?

[MindlessOath]

for the best track and street performance you might want to do a full coilover like tein and kw. they have the best comfort for a coilover setup.

utilizing spacific fluid, valving, and springs they can achive a ride close to the comfort setting in the stock setup (so im told, dont take my word for it).

other coilovers wont be so forgiving, but alot of coilover compaines are now making two versions, one compaitible with street and track and annother set for strickly track only.

swapping out springs not for just Eibach but a wide assorted list of springs will help bring performance increase and still keep it comfortable while keeping in dash settings. i hear swift is one of the best. also note that "mines" use the same eibach springs but they have "mines" laser etched on them and raise the price, ie gtr tax. RSR has the lowest of the bunch, but it could be dangerous around curbs, some guys in singapore have equiped them if you want to ask about them. There are more aswell. These are for those who dont want to track the car but occationaly.

coilover conversion like the cobb, amuse, JIC (i may have missed one or two) all go over the stock shock housing. they are adjustable and are stiffer more for a track setup without the costs assotiated with going full coilover. they are often less harsh too, and keep the in dash controls. This is probabably the best setup for those that want to track the car on the weekends or monthly but drive the car on the street mostly.

full track coilovers go without saying are unforgiving but will help put down power and increase laptimes by allowing to bring speed through the turns. Sofar i have seen the best suspension from autoselect and JRZ sofar.

of course these are all opinions, not facts.

also i remember hearing alot of people utilizing aftermarket settups have strange sounds comming from the rear of the r35. im not sure if anyone has figured it out or if it happens to everyone or not.

[descartesfool]

.......will help put down power and increase laptimes ..........of course these are all opinions, not facts.

A liitle too quick on the post button trigger finger!

[Sharif@Forged]

Sharif how would you compare and rate between coilover conversions likes those of Cobbs, Amuse and Top Secret with those of actual full coilover systems such as HKS hipermax, Sachs, Zeal, Tein and etc?


I just changed over to Top Secret sleeve conversion type and the rear suspensions clunks a bit on the top part, dont know if thats normal or installation error. Gonna go back up to troubleshoot it again. As the stock suspension uses rubber mounts while the aftermarket ones uses steel mounts, does it means aftermarket ones is going to make a fair big of clunking or knocking sound?

OK, the feedback I have gotten on the coilover sleeve setups, is they are better than just springs, but you will still overpower them as you get faster on the track.
The need for suspension upgrades varies greatly, based on driver skill level, tire choice, the track choice, and many other factors.

I usually tell my customers, to track their cars, and push them to a comfortable level...safely. Once they reach 7/10th's....that is when the vagueness and softness of the factory setup will reveal itself.

I think the worst thing one can do, is to throw a bunch of these upgraded suspension parts on the GT-R, without first seeing and experiencing the limits of the factory setup. That said, when the time comes, I think the logical step, is to skip the coilover sleeves, and move directly to a high quality, adjustable coilover system.

Descarte is spot on with all of his comments, as well.

[underpressure]

Anyone who wants to ride in my car on monday is welcome to jump in.

I'm running a full race setup w/ 900lb springs on all 4 corners. Lowered quite a bit.
Perfectly streetable. The JRZ triple suspension handles 98% of the pavement conditions better then the OEM setup while being seconds (numerous seconds) faster on track. The only thing the OEM suspension wins on is large transitions such as large slow transitions. IE rough bridges on interstate and only the really, really rough ones.
The reason the majority of 'race' or high end suspensions ride like shit is well... they are setup like shit. The dampeners are valved incorrectly for the given spring rates with the adjustments too coarse or just poorly designed.

This post has been edited by underpressure: Feb 16 2009, 08:21 PM

[Vic55]

for the best track and street performance you might want to do a full coilover like tein and kw. they have the best comfort for a coilover setup.

utilizing spacific fluid, valving, and springs they can achive a ride close to the comfort setting in the stock setup (so im told, dont take my word for it).

other coilovers wont be so forgiving, but alot of coilover compaines are now making two versions, one compaitible with street and track and annother set for strickly track only.

swapping out springs not for just Eibach but a wide assorted list of springs will help bring performance increase and still keep it comfortable while keeping in dash settings. i hear swift is one of the best. also note that "mines" use the same eibach springs but they have "mines" laser etched on them and raise the price, ie gtr tax. RSR has the lowest of the bunch, but it could be dangerous around curbs, some guys in singapore have equiped them if you want to ask about them. There are more aswell. These are for those who dont want to track the car but occationaly.

coilover conversion like the cobb, amuse, JIC (i may have missed one or two) all go over the stock shock housing. they are adjustable and are stiffer more for a track setup without the costs assotiated with going full coilover. they are often less harsh too, and keep the in dash controls. This is probabably the best setup for those that want to track the car on the weekends or monthly but drive the car on the street mostly.

full track coilovers go without saying are unforgiving but will help put down power and increase laptimes by allowing to bring speed through the turns. Sofar i have seen the best suspension from autoselect and JRZ sofar.

of course these are all opinions, not facts.

also i remember hearing alot of people utilizing aftermarket settups have strange sounds comming from the rear of the r35. im not sure if anyone has figured it out or if it happens to everyone or not.

Thanks for this post, so the RSR is the lowest spring only drop- do you have the drop parameters? Eibach seems to be too conservative for me. Do you have the drops in heights of various non coilover setups?

Thanks again for your time.

[First]

I would love to go for a full coilover setup but was unsure if the Top Secret roberuta kit I'm currently on would fit with other brands of coilover system. Anyone has any information on this?

I am not really liking the Top Secret sleeve conversion. It just doesn't feel right or "there". Currently looking at the HKS Hippermax III or Autoselects or the Zeals. Anyone could confirm is the Roberuta kit could fit with any of these?



And yes the rear end of my car is making some really weird sounding clunking noise ever since the Top Secret coilover sleeve conversion. Anyone with the Cobbs or Amuse setups experience the same? I was told it is caused by the pillowball mount as compared to the stock rubber mount. I am highly doubtful thats the reason though. I'm going to dismantle it again tomorrow and troubleshoot what the hell is going on. It just doesn't sound/feel right to make those kind of weird clunking sound. Its as if your drop a small piece of nut into a metal can/container and shake it. Sorta like that.

[underpressure]

I would love to go for a full coilover setup but was unsure if the Top Secret roberuta kit I'm currently on would fit with other brands of coilover system. Anyone has any information on this?

I am not really liking the Top Secret sleeve conversion. It just doesn't feel right or "there". Currently looking at the HKS Hippermax III or Autoselects or the Zeals. Anyone could confirm is the Roberuta kit could fit with any of these?



And yes the rear end of my car is making some really weird sounding clunking noise ever since the Top Secret coilover sleeve conversion. Anyone with the Cobbs or Amuse setups experience the same? I was told it is caused by the pillowball mount as compared to the stock rubber mount. I am highly doubtful thats the reason though. I'm going to dismantle it again tomorrow and troubleshoot what the hell is going on. It just doesn't sound/feel right to make those kind of weird clunking sound. Its as if your drop a small piece of nut into a metal can/container and shake it. Sorta like that.

Any slip-on coilover kit is going to clunk around as the suspension load and unloads. If the valving isn't correct and the spring looses contact w/ the perch, the perch will rattle around since there is nothing keeping it in place at that time.

If you are looking at spending the money for the Top Secret full kit stuff you might want to look at the JRZ RS Pro or even the triple like I'm running setup. Less cost and alot better ride/performance.

[First]

Thanks for the comment underpressure. Where could I find any reference to JRZ RS Pro?

I am planning to go for full coilover setup that has to be Compatiable with the www.roberuta.com kit that I am running now for elec. height up and down adjustments.

The SACHS from mines are a ridiculous prices to pay so my budget would be somewhere around 5k to 8k perhaps. Something more in line with "Not so ridiculous GTR tax".

I have heard very good recommendations about the Motons. Anyone has any other recommendations? That works with the kit i'm running.


I've since yesterday put back my stock suspension. The clunking sound is gone. Not liking it one bit. Now in a bit of a dillemma here. Also anyone know whats the stock springs spring rate?

[underpressure]

Thanks for the comment underpressure. Where could I find any reference to JRZ RS Pro?

I am planning to go for full coilover setup that has to be Compatiable with the www.roberuta.com kit that I am running now for elec. height up and down adjustments.

The SACHS from mines are a ridiculous prices to pay so my budget would be somewhere around 5k to 8k perhaps. Something more in line with "Not so ridiculous GTR tax".

I have heard very good recommendations about the Motons. Anyone has any other recommendations? That works with the kit i'm running.


I've since yesterday put back my stock suspension. The clunking sound is gone. Not liking it one bit. Now in a bit of a dillemma here. Also anyone know whats the stock springs spring rate?

The RS Pro's will be officially debuted this monday the 23rd at the VIR GT-R event. Pics, pricing and specs will be up on the forum soon after that. Compared to the Moton 2-way setup for $6k you are going to get alot more for your money. RS Pro's are going to be $6,200. I'll let Brian from JRZ fill in all the details and differences.

As long as the Roberuta kit work with the OEM shocks it should work w/ the JRZ's or anyone else just fine.

[Bryan @ JRZ]

Lets have a look at the facts.

The Moton 2 way is a twin tube street performance shock with compression and rebound adjustments. Both of these adjustments are blow off types of valves. There are 7 clicks of each. $6000 (so I've been told, I won't quote someone else's stuff) with springs that fit stock top mounts.

The JRZ RS Pro is a mono tube street/club/racing 2 way damper with compression and rebound adjustments. 12 compression adjustments and 13 rebound adjustments. We run blow off compression valving and shim/bleed rebound valving.Our RS Pro kit is $6200 with 2.25" racing springs (you can get whatever rate you want or our recommendations) , tenders, dividers, spherical bearing (mono ball) top mounts, rebound adjuster extensions in the rear so you can leave your interior in, and adjustable gas pressure. Its alot of adjustment, but its also why I'm the JRZ on call engineer 7 days a week. If blow off and shim/bleed sounded like Greek; come to the tech seminar at VIR and I'll happily put it into English.

This Moton damper has just been "released" as of PRI '08. We came out with a twin tube street shock 3 years ago (the JRZ RS). The twin tube dampers are good on track as well, they're just not as crisp. We made the twin not not as crisp because it soaks up more road disturbances that way. The reason that we don't have a twin tube kit for the GTR yet is time to market. Since the compression adjuster would be on the front fork we have to design a special twin tube front fork for the GTR and that would have taken more time. We would rather get you a wide array of shocks to choose from than just one. The RS Pro, race double, triple and 4 way all have the same front forks.

Yes the RS will be cheaper when it comes out (significantly compared its "technology sharing" rival) but don't bank on it for another couple of months since our R&D guys are up to their ears with new projects.

If there are any other specific questions, please call me, I dont want to clog the forums with whoring .

If you don't have my cell # PM me.

As far as the lifting kit goes, it looks like something that would fit on but I'd need the specs to be positive that it would sit on our spring perches happily.

[descartesfool]

Curious as to why the JRZ's are being run with 900 lb/in front springs that essentially the same as the OEM ones. Eibach engineer told me that their factory measurements in Germany of the GT-R's springs came out at 799 lbs/in at stock ride height rising up to 862 lbs/in under higher spring compression. The Eibach springs they are selling are 848 lbs/in at resting ride height and he told me they simply designed a spring set that gave stock wheel rate with a slight 0.8" drop in the front. Nismo Clubsport springs are slightly stiffer than OEM at 1036 lbs/in in the front. So 900 lbs/in is just about 4% higher than OEM, which almost nothing at all. I can see that rears at 900 lbs/in are a whole lot stiffer than both the OEM at 438 lbs/in, Eibach at 485 lbs/in and Nismo at 538 lbs/in, moving the car away from understeer toward oversteer. But why not stiffen up the overall roll rate more? Stock rate in front is more street than race. What is the thinking behind that choice of 900 all around without increasing front over stock? My track usage for other cars is more in terms of doubling or tripling OEM rates (or even more) to keep tires from de-cambering.

I still haven't seen what the suspension motion ratios are for the GT-R, so I don't have a feeling for the wheel rates from the spring rates, but I am wondering why track suspensions are not more in the 1500 lb/in and up in terms of front spring range.