Urethane Injection

[Hungryhippo]

anyone tried urethane injection in the side sills? intereted in doing it to my car but would like to hear if anyones had any positive or negative experiences.

[dano4127]

sorry i cant help you with your question, but i am interested to know what you are talking about can you elaborate?

[discopotato03]

I have seen it done to rally cars , lightweight means of stiffening up the shell .

[Hungryhippo]

Heres a link to one of the companys that do urethane injection. you basically drill some holes in your side sills and b pillars and pour in the mixture that hardens inside and stiffens up the chassis.

these guys sell it for 19000yen and another 50000 to 60000yen for putting it in your car, or you can DIY but if you make a mistake while putting it in the sills it is impossible to remove.

All the positive reviews ive read are from people who've used it and had success. All the negative reviews are from people that havent tried but point out all the things that could potentially go wrong with it

[Duncan]

lol, well I've done it but got no feedback yet, the car is awhile away from the track...we just used boring old heatproof expanding foam. Sills, A and B pillar and chassis rail (still to go)

[GTRgeoff]

Won't save an engine though mate

I should know...

[Duncan]

lol nothing will save my engines.

So you've done it? what did you think? Obviously the car i've done has a cage as well so I'm not expecting to feel any difference.

[Hungryhippo]

yeah, im interested in if its a viable option instead of a roll cage.any tried it on a car without a cage?

[funkymonkey]

did it on the ae86 without any other forms of bracing (only because it was gonna be acid dipped) as a test.

Flex was about 10mm along the B pillar with a jack on full height under the engine crossmember without any form of bracing.

with the urathane expanding foam in the door rails flex was 6mm.

with the roll cage mounted, the flex was 1mm.

I didn't find it doing wonders for the car, a good solid rollcage is much better IMHO. If you are gonna use it, make sure its not a polymer (urathane has many different variants) that absolbs moisture... although the whole idea of expanding foam is the air bubbles in it, which could be home to condensation.

[Hungryhippo]

thanks for all the replys everyone.ive managed to get my hands on a nice roll cage from a one make series race car:).

is it worth the extra effort to have it welded in or should i just bolt it in?

[r33_racer]

obviously welding it would provide more strength and a permenant fixture...however if it needs to come out at somestage then its gonna be a bitch. Bolting might be the case then. Personally i would weld it in, but im a fabricator so im completely biased haha.

[Hungryhippo]

Got the cage welded in. sooo much nicer now.better braking and better handling.very happy

[GTRgeoff]

Sorry Duncan, never answered. I've never done it and find the concept difficult to explain in the lack of structural improvement it will offer other than crush resistance. A cage and seam welding/added stiffening is the only solution.

The only ways to measure a real difference are to use a calibrated floor and point measure device or a chassis dyno. In a sloppy car it may help, but there are other more realistic ways of dealing with sloppiness.