Theory Of Lighter Racing Chassis?

[Digital Liquid]

Ok, I have been thinking about getting a lighter chassis for my NTC3. But I have come across a statement that made me have second guesses about switching it out. Hopefully someone can shed a little more light on it for me.

In theory, you switch out the stock chassis for a lighter racing chassis to:
--- Give your car a little more snap off the line ( increase acceleration)
--- To improve handling (especially cornering)

Here's the statement I read which got me thinking about this. But by switching to a lighter chassis, you also raise the center of gravity (COG)higher. Becuase you are not as bottom heavy as you were to start with. Thus, giving you some negative handling characteristics.

Has anyone experienced this, or is the weight amount too small to even see any negative effects of raising the COG?

It seems that even the smallest changes to my touring car make a significant impact on its handling and performance (unlike my MT's), so it seemed like a valid statement. Anyone got any answers or personal experience from swithcing to a lighter chassis?

Thanks.

 

[Diver6127]

Well, with the lighter weight, yes the car will sit higher but any racer worth their salt won't change the chassis without doing the following adjustments ...

1. Wheel alighnment
2. Suspension balance
3. Ride height

Average ride height is 4 1/2 - 6 mm. That is adjusted with the threaded shock bodies using the ride height tool. Also adjust the droop according to your track surface. Once the ride height is adjusted you take the car to the suspension tweak board and get it balanced. Reason for this is to have a straight hole shot as well as balance when entering and exiting turns. The HUDY board (wheel alighnment) will of course, take care of toe, camber and caster.

You can't just change the chassis and leave it as is and think that all will be fine. Adjustments need to be done in order to reap the benefits of a lighter chassis.

COG, is important but also not the limiting factor against getting a lighter chassis.

 

[Digital Liquid]

Thanks Diver, I knew you were the man on this stuff. Still being a newbie to the touring car world and just starting to race them as well (not formally yet, simply w/ friends), leaves me w/ alot of stuff to figure out.

BTW, I was actually looking at the 3Racing chassis and I saw that you mentioned that you have one. Can you give any comments on it (+) and (-)? Thanks.

 

[Diver6127]

I like the beefiness of the 3racing chassis, 4mm. It has the cut outs to keep the weight down. It's actually a little bit heavier than the standard chassis BUT not by much. The weight difference is very Very VERY slight. I got tired of tweaking the chassis after a few hard hits and went with a beefier chassis as opposed to a lighter chassis of 2.5mm titanium. Simply put, the 3racing chassis I got from eBay was $38 + shipping and the Hardcore titanium was $100+.

I know that titanium is more rigid and there are other things that add to it but I didn't have the cash to just "try" to see if I like it.

The 3racing, 4mm aluminum chassis is a great. Good and durable if you're bashing at the park with friends. It's "fine" for racing but I may try the BMI racing chassis next year becuase it has a built in tank guard.

I would recomend the 3racing chassis but see if it's on eBay first. There are a few people selling them from time to time.

 

[710baby]

go to www.3racing.hk.com
& check out www.speedtechrc.com

 

[Digital Liquid]

Thanks for the info. I actually just scooped up the Team Integy Chassis and am waiting for delivery. Here is a pic. It looks very identical to the 3Racing chassis. They are probably the same thing. I will post some feedback on it, after it arrives.

Team Integy 4mm 7075 Chassis:

3Racing 4mm 7075 Chassis:

Later....

 

[Diver6127]

They are the same exact design. Both good products. You will be very happy. Just remember, you may have to adjust your ride height because it's a 4 mm chassis. Do that with your ride height tool that came with your NTC3, if you have the adjustable shock bodies.

 

[Digital Liquid]

Giving an update....

I got the Team Integy Chassis in and compared it to the stock chassis. Here is my brief summary on it: (+) means good, (-) means bad:

(+) - Thickness ~ 4mm thick for less chassis flex and stronger

(+) - Pre-drilled Screw Holes ~ They are alot deeper than the stock holes, thus less chance for a screw to hang out from the bottom of the chassis

(+) - Cut Out Design ~ Makes working on the car easier

(+) - Color ~ A bronze/titanium tone which looks nice

(-) - Weight ~ It is alot heavier than the stock. The stock chassis weighed 187 grams. The Team Integy chassis weighed 255 grams. That is a difference of 68 grams.

 

[Diver6127]

That's why I'm getting the HCR Titanium chassis for next season. Lighter by design but stronger due to the metals characteristics.

The NTC3, is my backup racer but it will be seeing some track time.

 

[Silent]

I read into DL's opening statement that the COG is increased not because the car is lighter and therefore sits higher, but to mean the car has less "low" weight. I think if you could shave the 20 grams off the TOP of the car, it would handle alot better.

I rebuilt my NTC3 using an RDLogics chassis. It shaved 28 grams I believe. But my lap times weren't nearly as fast - the overhaul hanling had changed to a loose condition. I changed it back to the oe blue, not to say I might have gotten it to handle as good eventually.

I will be trying the HardCore chassis out next week in my kit NTC3 though. Its only 10 grams lighter I believe, and I'll set the suspension up stiffer to compensate.

 

[Digital Liquid]

I read into DL's opening statement that the COG is increased not because the car is lighter and therefore sits higher, but to mean the car has less "low" weight. I think if you could shave the 20 grams off the TOP of the car, it would handle alot better.

That's exactly what I was trying to say. I was thinking the same thing, that you would need to lose the same % of weight off the top in order to compensate for the weight loss from the lighter chassis.

Anyway, post your opinion on the HCR chassis when you get it running. I would like to get some comments on it and what you had to do differently to your set-up when you ran w/ it.

 

[Diver6127]

I know what DL was saying. It also seemed as if he was referring to a direct swap and not changing the settings. That's why I told him to change settings to compensate. His rolling mass would be different and can't expect his rollcenter to remain the same.

I myself am going to get the Titanium Hardcore chassis. Lighter yes, but more rigid and that will also call for a diferent set-up. I'm sure the inherrant push in the NTC3 will be amplified a little bit because of the stiffness. Only time will tell and that time won't come till april.

 

[Silent]

I did the RDLogics in my RTR NTC3. The HCR chassis is already in my "kit" NTC3, installed AFTER I put a one-way in it, so it wouldn't be a good comparison. The kit was extremely loose with all that turn-in the one-way was giving me, so maybe the stiffer chassis will help with that.

A guy at our club had that setup, with a blade and stiff springs, and he was very fast.