2nd hand Proflex kit. Urgent advice needed!

[Rallyman]

I had been thinking about replacing the OEM suspension of my TME but given the cost of quality dampers I had almost forgot about the idea.

Today I have been offered a 2nd hand 'like new' Proflex 3-way set (4 dampers |PLS| springs) for the equivalent of 1100 quid. They have been used in a road car by a rally racer who bought them for his Gr.A car but ended up using Ohlins, and fitted the Proflex to a road Evo VI for a few weeks only.

The seller is very interested in selling them (and other parts in the lot) without the hassle of running an ad for a few weeks, so he has set very attractive prices. As an example, he was offering brand new 18x8 Raceline wheels for 70 quid each (sold already).

They seem to be good value to me and I'm very tempted to buy them but I have to take a decision very fast.

Are they too harsh for road use? What about those horror stories related to their maintenance? I do low mileage with my Evo anyway.

I asked him about the springs and he mentiones they come with 90 and 80 for front and rears. I have no clue if he is talking about lbs or kg.

[Rallyman]

I forgot to mention the set includes Gr.A top mounts. I guess they are a pillowball type.

Setting them will not be a problem, as I have access to rally teams who run this type of suspensions in their Evos.

[Claudius v1.4]

[QUOTE]<font size|EQU| 1 >Original Post:</font><!--1-->

Are they too harsh for road use? - Absolutely not. OK, it depends on the spring rate. Above 6 kg/mm they become firm. With soft springs, ie. under 6 kg front and 5 rear, these dampers will be MORE COMFORTABLE than OEM, and SO MUCH BETTER. No comparison.

What about those horror stories related to their maintenance? That is bull****. People who say that these dampers are high maintenance do not have them and probably have never seen them. They are self-lubricating anyway.

I asked him about the springs and he mentiones they come with 90 and 80 for front and rears. - That is what my friend the rallye driver always says, too. 90 means 9 kg/mm. I have 8 in the front, 7 in the back. I would like 10 and 9 now that I use slicks. Tell him 90 will be too hard for road tyres, especially on wet surface and result in understeer.QUOTE]

Whatever you do, make sure you buy these dampers IMMEDIATELY. You can get springs the rate you want for approx 50 EUR each. 1100 GBP is dirt cheap, go ahead! (I am selling Dynamic Dampers which are basically the same with springs for GBP 2000!) If you dont buy them, I buy them!!

[evo400]

it is Nm/ mm not kg/mm wrong use for kg's force x lenght
they sound like a bargain wouldn't be talking about it go and buy them quick

[Rallyman]

Got them!

I got up this morning and drove over 200 miles to take a look and pick up the Proflex shocks. I ended up bringing with me a WRC-type kevlar guard too.

The springs are 90 and 80. Following your comments, maybe a bit on the harsh side for road tyres. Anyway, I'll fit 18 slicks for track days as soon as I source a set of wheels. Compomotive MO are the main candidates at the moment, as I don't have enough budget for super light wheels.

The Gr.A top mounts look great, but maybe they are an overkill and the Gr.N type would be enough.

The guy is also selling a pair of Recaro seats (I think he is asking EUR 700 for them) and a rollcage (not the welded type). Let me know if anyone has interest in these items and I'll get you in touch with the seller.


Thanks for your comments

[Claudius v1.4]

<blockquote><hr><font size|EQU| 1 >Original Post:</font><!--1-->
it is Nm/ mm not kg/mm wrong use for kg's force x lenght
they sound like a bargain wouldn't be talking about it go and buy them quick<hr></blockquote>

Na, it's N/mm. Which is 9.81 times more than kg if you know what I mean.

As long as we know what we are talking about...

[Claudius v1.4]

Good job muchacho! :) :) :)

Make sure you do not get heavier wheels. If the wheels are the same weight, the car will brake less good. So they really should be lighter. Why do you need 18 inch wheels? To fit brakes?

[Rallyman]

Claudius,

I'm not a fan of fitting larger wheels just for the sake of it. I need a second set of for 'special' occasions, and since I have access to free 18 used (but usable) slicks for track days I have decided that it will be worth going the 18 route.

Also, there is a very small price difference on P Zero Assimetrico between the 225/45x17 (@EUR 183 VAT and fitting included) and 225/40x18 (@EUR 194) at my local tire supplier. Following the comments on this site those are my next choice, after Bridgestones (tried S01, S02 and S03) disintegrate at an alarming rate on tarmac.

Sorry if I sound dumb. What are the physics behind worse braking with a larger wheel of the same weight and rolling radius? Is it related to a bigger proportion of the weight being placed further out on the wheel/tire fitment?

[Claudius v1.4]

Is it related to a bigger proportion of the weight being placed further out on the wheel/tire fitment?

Absolutely. In the braking force calculation, the wheel radius will negatively affect the stopping distance if increased. If the weight of the wheeltyre combination is not changed. If you get lighter wheels, you can compensate for it, if the wheels are heavier it gets worse.

I can not for the moment justify buying 18 inch wheels and fit 362mm AP 6 pot because of the small improvement it gives compared to the cost. I can, however, get hold of very nice light 17 x 8 inch Speedline magnesium (or alloy) wheels for a very good price, so I am considering that for now.

Make sure you can get LOTS of 18 inch slick tyres before buying the wheels!

[Claudius v1.4]

The Speedlines are 17 x 8 and weigh 10.4 kg in alloy and 8.2 kg in magnesium.

[alex]

Rallyman,

Yes, it is angular momentum that you need to overcome. The way that the wight of the wheel is distributed across
its radius is the determining factor. So if you could get a larger wheel of a bit more weight with significantly different
weight distribution (more weight closer to the centre of the wheel) you could have less angular momentum to overcome
in a braking situation.

(note the angular momentum for a UNIFORM disk is given by Mang |EQU| I*omega
where I is the inertia for the the uniform disk calculated as (m*R^2)/2
and omega is the angular velocity of the disk equal to Vlinear*R)

Alex.

[evo400]

my 8x18 OZ F1 CUP SPLITRIMS are only 7.5kgs each very very light and you can tell to

[Claudius v1.4]

You double poster, you! ;)

[Rallyman]

Thanks for the comments.

So it looks that the weight of a wheel is not an absolute measure then. It is also important where the weight is located. That's a good case against fitting super wide rims like 18x9 instead of 18x8.

Claudius, how much do Compomotive MO 6 weight? How about the OEM Enkei?

[Claudius v1.4]

OEM Enkei 10.4 kg I was told, havent seen this myself. A guy from the rallye team weighed one and told me (over the phone).

Compomotive in 18 inch, I think are something like 12 or 13 kg, maybe more. Try calling them and see if they answer that question! Dont fit these.

[Rallyman]

Who else (besides Proflex) makes springs for Proflex shocks?

Claudius,
You mention I should expect to pay EUR 50 for each. For that money it's worth it to buy softer springs before even trying the 90/80 setup, because everything points to those springs being too harsh for road use, and I'll save in labour cost.

[mr_biz]

Claudius are U self-lubricating anyway ? :lol

See you on the road soon

[Claudius v1.4]

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