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post #41 of 99 (permalink) Old 10-06-2012, 11:09 AM
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LOL nice backtrack.

Now you you say you want to redesign the chassis, engine block and transmission casing to have a rigid mounting? c'mon. Nobody is perfect, just admit it and move on. Maybe a couple guys got on your case, but I don't think they meant anything personal.

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post #42 of 99 (permalink) Old 10-06-2012, 01:17 PM
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my 1st gear is 68-70 MPH shift into 2nd gear can be pretty harsh Rob.
Hey robains, can you really go 70mph in 1st gear? Thats amazing.
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post #43 of 99 (permalink) Old 10-06-2012, 05:10 PM
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Hey robains, can you really go 70mph in 1st gear? Thats amazing.
This kind of gearing makes perfect sense at the track because how often are you below 40mph at the track? Put another way, how often do you need first gear at a race track? This way you actually use all of your gears. That's my guess.

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post #44 of 99 (permalink) Old 10-06-2012, 05:29 PM
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LOL nice backtrack.

Now you you say you want to redesign the chassis, engine block and transmission casing to have a rigid mounting? c'mon. Nobody is perfect, just admit it and move on. Maybe a couple guys got on your case, but I don't think they meant anything personal.
Hay, all I ever say, is that you (I) can design (for) anything…I never said it would be easy! Hell, if it was easy to design stuff, nobody would need engineers. I intentionally said too little to taunt you guys and I just had to elaborate because I got collared. Can a drive train be solidly mounted to a chassis? YES…all Formula-1 cars are designed that way. Is it a good idea to replace the drive train’s isolators in a street car with a metal? No!
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post #45 of 99 (permalink) Old 10-06-2012, 08:59 PM
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post #46 of 99 (permalink) Old 10-07-2012, 04:02 AM
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post #47 of 99 (permalink) Old 10-07-2012, 06:19 PM
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so.... does admitting to intentionally giving bad advice "to taunt" make you look better then making a simple mistake?
anyway.. my last post on this matter.

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post #48 of 99 (permalink) Old 10-07-2012, 07:09 PM
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Look, my taunt was not misinformation, it was a challenge to design and looking for feedback. I stated that our Lotus chassis is well designed to absorb shock and vibration (post #7)...the taunt! And here is why; even though the Lotus chassis is made from 6063 aluminum (a weldable grade of aluminum), Lotus chose not to weld it, but bond it! Bonding is a much more expensive process but much better for shock and vibration. These joint are the best possible joints for vibration loads…as proven by their road test…another one of my statements in post #7. Had this chassis been only welded, I bet you it would have cracked up even without a solidly mounted engine.

Post #10 was my challenge by asking the question why did you not design solid engine mounts…letting you assume that it was a simple R&R of the materials in the OEM locations - knowing damn well the scope of the design problem…I just did not say that a whole drive train would have to be designed to accomplish this at that point in time.

I got the feedback I was looking for. I found out that HyperSport (in post #28) have absolutely no engineering support because they even tried to install solid engine mounts in the OEM locations (as explained in post #40) and therefore qualify as my favorite mechanics thinking they are engineers as I so eloquently stated in posts 10 and 38. I’m a lot slyer (and complex) than I lead on to be…
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post #49 of 99 (permalink) Old 10-08-2012, 07:48 AM
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even though the Lotus chassis is made from 6063 aluminum (a weldable grade of aluminum), Lotus chose not to weld it, but bond it! Bonding is a much more expensive process.
be…
Are you taunting us again?
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post #50 of 99 (permalink) Old 10-08-2012, 07:51 AM
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Not intentionally this time…but I’ll bite…what you got?
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post #51 of 99 (permalink) Old 10-08-2012, 12:27 PM Thread Starter
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Hey robains, can you really go 70mph in 1st gear? Thats amazing.
Yes, with my ECU qualification map switch (if you watch one of videos from BW, you'll see me hit the switch for map change) which allows up to 9000/9100 rpm which extends 1st gear to about 70 mph. Standing starts however would suffer.

Interesting debate, still listening. <@¿@> do you have a name? - apologize in advance if I should know.

Cheers, Rob.

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post #52 of 99 (permalink) Old 10-08-2012, 12:51 PM
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<@¿@> Said : I’m a lot slyer (and complex) than I lead on to be…

You are awesome

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post #53 of 99 (permalink) Old 10-08-2012, 02:01 PM
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I know of an Elise with supercharger and motor mount inserts... Keeps breaking studs at the head/intake manifold...

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post #54 of 99 (permalink) Old 10-08-2012, 06:15 PM
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Interesting debate, still listening. <@¿@> do you have a name? - apologize in advance if I should know.
No apologies needed…I guess I didn’t say...not even in my profile. There's some background about me, but not my name…just my nickname...Julius Jonas Jodelė...I'm Lithuanian BTW, so the J-s are pronounced like Y-s...just like the Germans do it.
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post #55 of 99 (permalink) Old 10-13-2012, 07:11 AM
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Yes, with my ECU qualification map switch (if you watch one of videos from BW, you'll see me hit the switch for map change) which allows up to 9000/9100 rpm which extends 1st gear to about 70 mph. Standing starts however would suffer.

Interesting debate, still listening. <@¿@> do you have a name? - apologize in advance if I should know.

Cheers, Rob.
I think something's missing from the equation here. Simply adding 1000 revs will not take a first gear up to 70. The gear itself would definitely need to be changed. First gear tops around 40-45. (trust me I've tried leaving it in first for some smaller AutoX courses and it goes pop-pop-pop frustratingly early). The extra 1000 rpms would add about 12%.

Second gear normally tops out around 65-70 (245 17" hoosiers, stock tranny), so before one cries Awsome, keep in mind that whatever combintion of larger tires, and special gears get you to that speed in first will make it feel just like you were using the stock second gear to pull away from the line. The higher revs help with power at the top end of course, but not off the line.

If starts are not important or the low end torque is increased significantgly, that's probably fine, otherwise it would be un-fun on the street. (the stock configuration will get underway in second with a gentle use of the clutch)

If it goes that fast in first then first gear has less mechanical advantage for sure. The question is do the engine mods make enough power to make up for it...

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post #56 of 99 (permalink) Old 10-13-2012, 07:17 AM
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Oh and somewhat more on topic, does anyone know the hardness of the rear mount sold by BOE? I have one that I was given as a gift, and I think it's probably going to be helpful since I get some wheel hop-hop-hop on AutoX starts, but I REALLY can't afford to damage my chasis.

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post #57 of 99 (permalink) Old 10-13-2012, 10:10 AM Thread Starter
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I think something's missing from the equation here. Simply adding 1000 revs will not take a first gear up to 70. The gear itself would definitely need to be changed. First gear tops around 40-45. (trust me I've tried leaving it in first for some smaller AutoX courses and it goes pop-pop-pop frustratingly early). The extra 1000 rpms would add about 12%.

Second gear normally tops out around 65-70 (245 17" hoosiers, stock tranny), so before one cries Awsome, keep in mind that whatever combintion of larger tires, and special gears get you to that speed in first will make it feel just like you were using the stock second gear to pull away from the line. The higher revs help with power at the top end of course, but not off the line.

If starts are not important or the low end torque is increased significantgly, that's probably fine, otherwise it would be un-fun on the street. (the stock configuration will get underway in second with a gentle use of the clutch)

If it goes that fast in first then first gear has less mechanical advantage for sure. The question is do the engine mods make enough power to make up for it...
You are indeed missing something ... I'm running a Quaife box with the following gear set and final:

1st 2nd 3rd 4th 5th 6th Final
2.545 1.929 1.563 1.333 1.167 1.050 3.857

I'm not adding 1000 rpm in my qual map, going from 8800 to 9000/9100 (ish).

Here are the MPH calculations from Apex Garage using S01 190/230 -17 (measured about 24" diameter) and one with Hoosier A6 225/45-17 (25.1" tire diameter).

The advantage of the gearing is the close ratios and speed of shifting ... the Quaife is still heal/toe box so no benefits there.

Quaife offer a variety of ratios and finals, my car is not a street car. I wouldn't run the Quaife box on the street.

OEM transmission @ 8500 rpm on A6 Hoosier (about):

1st 45 mph
2nd 68 mph
3rd 94 mph
4th 119 mph
5th 152 mph
6th 171 mph

Rob
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post #58 of 99 (permalink) Old 10-13-2012, 10:21 AM
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another vote against solid mounts. (Mechanical engineer here as well.. for what its worth..)

There are certain engineering choices that you just don't do, unless you have a damn good reason and a ton of analysis and testing behind it. One of them is to rigidly mount a heavy vibrating mass to a critical structural part made from aluminum without any damping. You just don't do it unless you have a ton of testing, because if sh1t breaks, its BAAAD. you are not talking cracked exhaust or balky shifts.. you are talking broken chassis.

if you want to take more deflection out of it: go stiffer, add a rigid intermediate shell for the poly bushing to press into the motor mount, or even some how add additional mounting points... But the difference between no damping and a little damping is huge when it comes to vibration fatigue in aluminum.

Steel, no problem in most cases. Aluminum, bad.

as far as having data to back it up. Nobody will have it, because this is something that is against common engineering judgement. By the way when Lotus do vibration testing on the chassis, the suspension mounting points are mounted on bushings, not solid points.

Heck.. its not just the chassis you risk cracking, you also risk cracking your tranny case or even engine block depending whether there are any flaws in the casting.

the rear subframe is steel, not alum. so any solid drive train would mound to the steel sub frame, technically, it would be "very" easy to add re-enforcement to the subframe. my gut tells me you would probably get better results out of re-enforcing the sub frame and using very stiff mounts, rather bolting in solid drive train mounts....

fyi - most real race cars have solid mounts, mine does. there is nothing special about solid mounts, i see them all the time. engine and transaxle are bolted straight to the chassis. but to your point - certainly its designed that way, on the other hand - its not rocket science either. there are two issues at work, drivetrain movement, and drive train flex, once enough movement forces flex in the frame, you have flex, and I am going to guess the elise subframe flexes... a good bit... so that solid mounts will just eliminate drivetrain movement and introduce lots of flex.

now, sure, the subframe on the elise does bolt TO the alumn. chassis. but there is a good amount of mass and length of material there. never the less, for the OP, i am going with my suggestion above - very stiff mounts and a re-enforced subframe. i am not convinced on the elise, for reasons mentioned, would get the full benefit of solid mounts. but, with a well thought out approach, i don't see solid mounts being "wrong" at all

i am sure his tranny can take solid mounting (god, i would hope so!) no idea about the yamaha block...

here is a thought - what did Newey do on his elise race car? maybe a call to wirewheel for a peek into how that car is built?

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post #59 of 99 (permalink) Old 10-13-2012, 11:08 AM
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the rear subframe is steel, not alum. so any solid drive train would mound to the steel sub frame,
In the spirit of the debates...

factcheck.com says this your statement is false.

3 of the 4 monuting locations for the motor/tranny are fixed to the aluminum tub. It's only the rear tranny mount that's fixed to the steel subframe.



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post #60 of 99 (permalink) Old 10-13-2012, 12:07 PM
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ha phil! i'll take your word over factcheck.com on these matters anytime, but hey ... 1 out of 4 ain't bad! (although i could swear the side mounts picked up on the subframe, guess they are on the tails then! i'll go back to not paying attention now )

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