MR2 Roadster Owners Club

The Workshop => Performance Related => Topic started by: Petrus on May 2, 2021, 12:00

Title: Snelbaard´s FMB
Post by: Petrus on May 2, 2021, 12:00
My PFL has a front tower brace, Snelbaards belly plate, Dev´s door spacers,  head steady,TRD rear lower arm braces.
Suspension is TRD Sportivo shocks&springs, rear roll centre spacers and a set of Whiteline ARBs.
Oh and it is under 900 kilo with the tank half full.

Thursday fitted the FMB:


MR2FMB1.jpg


I was surprised by the effect. Although it already has some bracing, the brace takes a lót and I mean a LÓT of ´give´ out of the front end.
It increases the directness of the feedback from the front wheels and thus allowing higher corner speeds. In mý case it is curing me of the old motorcycle
 racing bad of tapping the (rear) brake before peeling off.
Anyway, that is just the prelude to the crux of this thread.

Because of the definitely higher cornering speeds, I was expecting more rubbing through undulating (nicer word than bumy) corners. But no, it rubs LESS!! :o

So to confirm I went a bit detour coming back from Bubbly this morning. That is on purpose twó ´norm bends´.
Two medium (about 100 and 120 km/h) speed bends with weird camber and unflat tarmac. The higher speed one has negative camber, the lower speed one positive camber.
I am still getting used to the more direct feel so not nearly a warp speed difference but definitely going a few km/h faster than before.
The fast bend, nó rub. The other júst a toutch.
The latter toutch being the same as nailing it with a lót more effort under better road conditions with the lightened car on stock suspension at least 10 km/h less.
I am surprised.

HUH?? Why?
I had not expected it to affect this aspect and thinkng about it, I would have expected it to be wórse rather than better  :-\  :-*
The new train of thought to explain it is that the reduced flex transmits more force of the front springs to the réar, keeping the car flatter. In other words, the centrifugal force causes just a bit less roll. Less roll equalling less load on the outer front.

Double whammy surprise:
I had not expected thát much reduced give and the appearantly* reduced roll it a total surprise.

* by all means, in fact PLEASE! enlighten me if there is something else at work.

All in all added fun. Not just driving fun but also the stimulation of the grey cells  :))





Title: Re: Snelbaard´s FMB
Post by: Beachbum957 on May 2, 2021, 12:20
People forget that the chassis is a "spring" as it flexes, and an undamped spring at that.  Stiffen the chassis, and the suspension has to do a bit more work, changing the handling. This may show as slightly stiffer suspension and a sharper initial turn in.

Some people claim a FMB doesn't do much, but often they are using a cheap aluminum one they bought off eBay that really isn't very stuff. A well braced steel one like Snelbaards should make a difference. 

We have an original Tom's FMB brace (long out of production) that really stiffens the front, along with other braces like a TRD strut brace and an original Corky's breastplate which Snelbaard replicated.  Of all of the braces, the breastplate made the biggest individual change, but all of the bracing works well together and you can really tell on rough roads or quick transitions.
Title: Re: Snelbaard´s FMB
Post by: Petrus on May 2, 2021, 12:41
Quote from: Beachbum957 on May  2, 2021, 12:20People forget that the chassis is a "spring" as it flexes, and an undamped spring at that.

I am véry aware and thus cautious of bracing a real world road car. The chassis compliance is as you say part of the suspension and thus the roadholding. Hence (and because of ground clearance) not going to fit the big bed frame under the chassis ;-)

Still, had the logic of the effect on suspension compression wrong in this case :-O

QuoteStiffen the chassis, and the suspension has to do a bit more work, changing the handling.

This is why I beforehand not expected thís result.

Lóve being wrong :-)
Title: Re: Snelbaard´s FMB
Post by: 1979scotte on May 2, 2021, 15:38
Remember that FL cars have much more bracing in that area and the later cars have some very substantial bracing there indeed.
Title: Re: Snelbaard´s FMB
Post by: Petrus on May 2, 2021, 16:09
Quote from: 1979scotte on May  2, 2021, 15:38Remember that FL cars have much more bracing in that area and the later cars have some very substantial bracing there indeed.

The later cars have a whole different subframe. Not all that much about adding stiffness up front though. Have look at the below photo. Imo that is more about  extra crash resistance further to the front combined with simplifying production.
This FMB for the PFL compares favorably imo with the crucial bit being the triangulating ´X´ Boris fitted. The things adds a real rigid ´bridge´ right where it counts.

(https://i.ibb.co/1T2Y7BC/DSCN2112.jpg)
(https://i.ibb.co/ZXLJV5z/Whats-App-Image-2021-01-28-at-17-13-25-1.jpg)

Regardless, the difference on mý PFL  makes me smile.
Title: Re: Snelbaard´s FMB
Post by: Joesson on May 2, 2021, 16:54
Quote from: Petrus on May  2, 2021, 16:09
Quote from: 1979scotte on May  2, 2021, 15:38Remember that FL cars have much more bracing in that area and the later cars have some very substantial bracing there indeed.

The later cars have a whole different subframe. Not all that much about adding stiffness up front though. Have look at the below photo. Imo that is more about  extra crash resistance further to the front combined with simplifying production.
This FMB for the PFL compares favorably imo with the crucial bit being the triangulating ´X´ Boris fitted. The things adds a real rigid ´bridge´ right where it counts.

Regardless, the difference on mý PFL  makes me smile.



Having recently spent some time under my PFL , on my back, I can say that removing the under tray from a FL likely means the " grey fingers" would also need to me removed and as @Petrus said the front end of the fingers are doing nothing to add to chassis stiffness there being little of substance at the front fixings.
Title: Re: Snelbaard´s FMB
Post by: Petrus on May 2, 2021, 18:14
Remembered a nice appropriate one:

Chassis flex plays an important role in the effectiveness of your sway bars. The stiffer your chassis is the more responsive your car or truck will be to changes to sway bar settings.

Thus my thought that the effect is less body roll seems correct.
Title: Re: Snelbaard´s FMB
Post by: Petrus on May 2, 2021, 18:33
Quote from: Joesson on May  2, 2021, 16:54the front end of the fingers are doing nothing to add to chassis stiffness there being little of substance at the front fixings.

I´d wager that the PFL profiled supports for the lower control arms are more rigid than the FL less profiled flatter tin.
The only improvement I see is the cross brace connecting to the chassis rails and foot wells but the mounting points to the new tin do not seem very rigid.



Title: Re: Snelbaard´s FMB
Post by: 1979scotte on May 2, 2021, 19:08
Quote from: Petrus on May  2, 2021, 16:09
Quote from: 1979scotte on May  2, 2021, 15:38Remember that FL cars have much more bracing in that area and the later cars have some very substantial bracing there indeed.

The later cars have a whole different subframe. Not all that much about adding stiffness up front though. Have look at the below photo. Imo that is more about  extra crash resistance further to the front combined with simplifying production.
This FMB for the PFL compares favorably imo with the crucial bit being the triangulating ´X´ Boris fitted. The things adds a real rigid ´bridge´ right where it counts.

(https://i.ibb.co/1T2Y7BC/DSCN2112.jpg)
(https://i.ibb.co/ZXLJV5z/Whats-App-Image-2021-01-28-at-17-13-25-1.jpg)

Regardless, the difference on mý PFL  makes me smile.

They make a great deal of difference on a pfl same as a front strut brace. Less so on a FL.
I know this because I've owned more than one mr2 and I've fitted different bracing on them. Even fitting TOYOTA FL bracing to a PFL.
The one in you photo is the later version there is another early FL I believe.

BTW why doesn't it have a bar across the front wouldn't that help stiffness?
Title: Re: Snelbaard´s FMB
Post by: Petrus on May 2, 2021, 19:36
Quote from: 1979scotte on May  2, 2021, 19:08BTW why doesn't it have a bar across the front wouldn't that help stiffness?

There is already a sturdy frame  profile going accross; twó actually; the spare tyre bucket rests on it and the other has the wheel screw down bolt fitting on it.

(https://myalbum.com/photo/rJ8zgMqiSbbu/1k0.jpg)
Title: Re: Snelbaard´s FMB
Post by: tom256 on May 3, 2021, 00:21
Quote from: 1979scotte on May  2, 2021, 19:08The one in you photo is the later version there is another early FL I believe.

Yes, this enhancement was introduced in 2004.02 with last car modification.
Title: Re: Snelbaard´s FMB
Post by: Petrus on May 3, 2021, 08:38
Quote from: tom256 on May  3, 2021, 00:21
Quote from: 1979scotte on May  2, 2021, 19:08The one in you photo is the later version there is another early FL I believe.

Yes, this enhancement was introduced in 2004.02 with last car modification.


As Goscinny & Uderzo wrote about Cacofinix´s art; opinions are divided about that.
Title: Re: Snelbaard´s FMB
Post by: WillM on March 28, 2024, 15:31
Hi is that brace available still anywhere? Id like one.
Title: Re: Snelbaard´s FMB
Post by: steveash on March 28, 2024, 23:00
Quote from: WillM on March 28, 2024, 15:31Hi is that brace available still anywhere? Id like one.

This is the thread you're looking for. (https://www.mr2roc.org/index.php?topic=70664.0) If it's not visible yet then you need to make a few more posts as certain features aren't available to new members.
Title: Re: Snelbaard´s FMB
Post by: Snelbaard on April 26, 2024, 22:03
Quote from: WillM on March 28, 2024, 15:31Hi is that brace available still anywhere? Id like one.

They are! Send me a DM if you'd like to get one :)