Can an ISF ride like a Lexus ??

[Jon Dee]

Recently I became the proud owner of a 2008 ISF with nearly 200,000km on the clock. Previous owners had "upgraded" the car with HKS coilover suspension, wider WORK wheels with lower ET, and 35-series tyres in front and 30-series in back. As a result of these improvements the car rides like a dray with a full complement of thumps, rattles and bangs.

Now, I am reliably informed that all early ISF's have a stiff "track orientated" ride and I should either harden up or go buy a LS or GS if I want a car with a decent ride. Convincing as these well considered and logical answers may be, they have not deterred me from embarking on a program of changes. By correcting some of the improvements that have been inflicted on this poor old workhorse, I hope that I can achieve a firm yet compliant ride worthy of the Lexus name. 

Bear in mind that I am not going to track this car, drag race, hill climb, tow a horse float, use it for an Uber or try and beat much newer high powered cars away from the lights. What I do want is a car that is a pleasure to drive, quiet, comfortable and responsive when required. Too much to ask ?? I intend to find out  

Cheers...

[Jon Dee]

First lot of parts have arrived... Bilstein's build quality is superb. I shall be assembling them with the factory springs as I am quite happy for the car to ride at the factory ISF height. All new rubber bits have been ordered for the installation of the new shocks. 

Cheers...

 

[Jon Dee]

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Rear discs are below minimum and front discs are getting close to minimum, so I have ordered a full set of new OEM brembo discs and pads.

[Jon Dee]

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My intention is to replace the existing 19" wheels with custom 18" wheels with offsets that will bring the scrub radius back to where the factory intended it to be.  I hope that they will be RS3 replicas as per this pic. 

Cheers...

 

[Jon Dee]

Placeholder for tyres 

Tyres are presently a bit of a problem. The sizes I need that will increase the sidewall height are not readily available, so further work required. The tyres will be selected to achieve the same diameter as the factory 19" tyre and wheel combination. 

Cheers...

[Bluethunder]

Is the mileage 200,000km or 200,000 miles? 

I use to have a 2009 ISF on stock suspension and didn't think it was over firm. 

[ubersonic]

Are you planning on selling the HKS coils?

[Jon Dee]

4 hours ago, Bluethunder said:

Is the mileage 200,000km or 200,000 miles? 

I use to have a 2009 ISF on stock suspension and didn't think it was over firm. 

"Firmness" is a entirely subjective... a bit like Goldilocks and the bears beds :) What one person call "hard and crashy" another may call "firm and sporty". I've never had the opportunity to drive a low miles ISF with stock wheels, tyres and suspension, so I can't comment on that. But coming off a E92 msport that did have an acceptable firm and sporty ride, I just know what is currently on my ISF is not acceptable. So I am going to the opposite extreme to make the ride quieter, more compliant and better able to handle imperfections in the road surface. Cheers...

[Jon Dee]

3 hours ago, ubersonic said:

Are you planning on selling the HKS coils?

Yes, but I'm in New Zealand so the cost of shipping to the UK may be prohibitive. 

Cheers...

[4969_LXS]

@Jon Dee I have an 08 ISF. Early cars like mine are undersprung and overdamped which causes a firm ride. 2013-2014 model suspension were the best OEM and they do bolt onto earlier cars, the rear bump stops will need changing though. Interesting reading your thoughts on the HKS suspension. Other F owners rate the HKS Hypermax S/X suspension highly in terms of comfort whilst keeping the body stable

[Jon Dee]

25 minutes ago, 4969_LXS said:

@Jon Dee I have an 08 ISF. Early cars like mine are undersprung and overdamped which causes a firm ride. 2013-2014 model suspension were the best OEM and they do bolt onto earlier cars, the rear bump stops will need changing though. Interesting reading your thoughts on the HKS suspension. Other F owners rate the HKS Hypermax S/X suspension highly in terms of comfort whilst keeping the body stable

Having compressed the factory shocks while off the car, I have to say the damping is definitely on the FIRM side !! On the other hand, the factory spring rates are very close to the popular SWIFT lowering springs. This indicates to me that with proper damping the factory springs should be able to deliver an acceptable ride. Bilstein tuned their B6 ISF dampers to work with stock springs and ride height. The coilovers in the car are the HKS Hipermax MAX IV GT with 16F and 10R kg/mm springs that are a lot firmer than the factory rate. 

For track work on smooth surfaces firm springs are seldom a problem providing they have quality damping. Aftermarket coilovers are designed to improve performance for track/racing applications. In general, they have the opposite effect when used on the road where the surface is less than perfect. I don't intend to track my car, so ultimate grip on a racetrack is not important to me, but ride quality on our substandard roads, is important. 

Cheers...

[Jon Dee]

For some reason this forum does not allow me to edit my own posts from yesterday ??? I've been on a lot of different forums and never struck this before... how bizarre, how bizarre 

Anyway, brembo goodness is now under the bench. Install will have to wait until I do the shocks and that has to wait until the backordered rubber bits arrive  

Cheers...

[NothernDan]

If you want a nice compliant ride.....

Airlift all the way.

[Jon Dee]

2 hours ago, NothernDan said:

If you want a nice compliant ride.....

Airlift all the way.

No argument with that. I actually looked into airlift conversions a while back, but they are a bit spendy, and introduce another potential maintenance item. I could have bought a nice LS460 on bags for less than I paid for my ISF, but that style of car is not what I was after.

Guys who fit Bilsteins to their ISF's are outnumbered 100:1 by those who fit BC or similar coilovers and big wheels to their cars. But the guys with the Bilsteins and otherwise stock suspension are usually very happy with the improvement in their ride, while the lads with the  BC's are swapping springs, wheels and tyres to try and fix tyre wear, harsh ride and handling problems 

I'm happy with a "sporty" ride, and I once had a car with cut springs that cornered on the bump stops and I thought that was cool  But I have moved on since then...

Cheers...

[Cactus]

Tein edfc

kwv3

ohlins

[Jon Dee]

As fate would have it, I found a set of OEM ISF wheels in very good condition for sale. They were fitted with Potenza S007 tyres in factory sizes and had a decent amount of rubber left on them. Since I like the look of the factory wheels, I bought them  The plan now is to run the car with the OEM wheels plus Bilsteins and evaluate the ride. 

Presently working on assembling the OEM suspension (that came with the car) with the Bilsteins. Once I have them ready to install I will be changing out the HKS coils. Probably run with the Kiwamis initially just to see what changes, and then put on the OEM wheels to see what difference they make. 

Cheers...

[EP80]

Look forward to seeing what you think of the Bilstein and factory spring setup. Considering this for mine as a fit and forget setup. 

 

[Jon Dee]

14 hours ago, EP80 said:

Look forward to seeing what you think of the Bilstein and factory spring setup. Considering this for mine as a fit and forget setup. 

For sure I will be posting my opinion on how the new setup works  Also some thoughts on how easy or difficult the swap is for a DIY exercise. See the next post !!! 

Cheers... 

[Jon Dee]

Just finished extracting the springs and some of the buffers that I am reusing from the factory suspension. Assembling the Bilstein version was pretty straight forward as far as getting all the bits together. Then the head ***** started... Lexus requires specific handing and alignment of bottom and top fixings, and in the rear the springs are face in opposite directions !!!! I've replaced struts and shocks on a few cars (including fresh Bilstein B4's on my E92, but never have I come across anything as complex as the instruction for mounting shocks on the ISF  

I guess it is kind of like the nightmare tyre fitters must have when they find out that the ISF has a dedicated wheel for each corner of the car and they have to fit asymmetric directional tyres   Now to get under the car and see what has to be done to fit the new suspension.

Cheers...

 

[Jon Dee]

Front shocks are installed... pretty straightforward job. Contrary to the wisdom of the interweb, I was able to extract the HKS shocks and install the Bilsteins from the rear side of the wheel assembly. Didn't have to remove or disconnect anything except the wheel sensor bracket and the bolts that hold the shocks top and bottom. Can't guarantee that this would work for 100% OEM shock assemblies, but I can't see any reason why not unless they are longer top to bottom than the Bilsteins. 

Tomorrow I shall see if I get lucky with the rears  

 

[Jon Dee]

Overalls are in the wash so in the interests of science I decided to take the car for a short drive to see what difference just having the Bilsteins up front would make. Entirely subjective, but I think I noticed a reduction in the amount of rattling heard when driving over imperfections. This is to be expected as softer springs mean that impacts are less jolting. Impacts are now more like thuds than bangs, so definitely heading in the right direction. The front is now about 5cm higher than it was before and that is the difference between "stupid low" and just low  I am more than happy with the new look and am not expecting to see much change in the height at the back when the Bilsteins are installed. 

Pictures tell the story so you can make up your own mind how it looks...

Cheers...

[EP80]

Thanks for the pics. I didn't realise that the front shocks were so straightforward to get fitted. Apparently one arm needs to be unbolted on one side at the rear but thats it. Be good to see how you get on and then see how the handling changes.

[Jon Dee]

Rear shocks were a bit more complicated than expected. Turns out the rear HKS were set at maximum height for the nose down a$$ up posture that is the fashion these days  Result was that the shocks were about 45mm longer overall than standard and I needed to unbolt the arm from the knuckle to release them. Bilsteins are also a bit long to fit them without unbolting the arm. Unbolting it was the easy part... jacking up the arm and getting the bolt back into the bushing was the trick part. That's a lubricated self aligning bushing not a rubber bush, and getting it lined up to push the bolt back in was a trifle frustrating !!!! 

So just have to finish off tidying the RHS tomorrow then onto the LHS.

Cheers...

[Jon Dee]

Well, the rear Bilsteins are installed and I managed to get the boot trims installed and everything tidied up yesterday. Unable to contain my excitement, I went for a short drive even though it was getting too dark to get any decent photos. And the improvement in the ride was immediately apparent... likewise the reduction in rattles and bangs  

Thanks to the 35 series front, 30 series rear tyres there is still a bit more thump than I would like when hitting larger imperfections in the road surface. It will be interesting to see if swapping to the OEM wheels with 40 and 35 series tyres will show a further improvement. I'll be looking to do that when the weather improves. 

Rattles and bangs have now been reduced by 95% to the point where they are no longer a source of annoyance. There is far less rubber cushioning with the HKS rears than with the OEM mounting hardware, and this was obviously causing a high level of noise/vibration to be trans mitted to the chassis. Note that I can only compare Bilstein with HKS and I would expect the difference between Bilstein and OEM to be less remarkable. 

At this point the rear of the car is higher... not enough to bother me as it now matches the front  

Cheers...

[EP80]

How does the handling compare to the coilovers? I take it that compliance is better? Glad you got it sorted.