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Posted: Mon Feb 27, 2006 9:59 pm Post subject: longitudinal vs transverse

I'm new, love me!

I'm still in the early planning stages of my car. I know I want to use a mid-mounted ls1, but I'm still wavering on whether to use a transverse or longitudinal trans. I definitely prefer the look of a longitudinal mount, but it seems like with a transverse (shorter wheelbase/lower weight?) I might get better handling. Can anyone give me tips about the tradeoffs?

Something else I thought was, with a transverse, will I need to mount the radiator and/or fuel cell and/or whatever in the front to balance out the weight. I also prefer the look of having the radiator in the rear and the simplicity of not having to run coolent lines under the cab.

I'm also wondering if there's any automatic transmissions out there that would be a good match for this application. Maybe with a limited slip? All the longitudinal transaxles I know off the top of my head are manual.

Posted: Mon Feb 27, 2006 10:56 pm Post subject: Re:longitudinal vs transverse

Transverse: one driveshaft is longer than the other, this fact results in something known as torque steer. I.e. one wheel gets more power i.e. funk situations while under power during a corner and standstill burnouts

I have a question for your automatic question. Why are you going to hand build a midengine RWD V8 powered beast, then slap an automatic transmission on it? For what purpose are you going to build this car?

Jacob
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Current build: 91 Toyota Cressida
Mods: 2jzgte, R154 (5 spd), Exedy Carbon Twin disc clutch ($), oem MK3 LSD, Turbonetics T61(500hp+fast spool), Apexi SAFC II (piggyback comp), intank Bosch 044, adapted 240sx coilovers, JDM VIP style body kit/rims.

Posted: Mon Feb 27, 2006 11:16 pm Post subject: Re:longitudinal vs transverse

I knew there'd be questions about that. The reason is that it will hopefully be somewhat of a luxury sports car and a daily driver. The easier it is to drive, the better. I may eventually add a full electronics/audio system, GPS, TCS, even (dare I say it) ABS. All of that's down the road; first step is to get it rolling. But so you know, I don't even know if I'd be happy with an automatic. My current daily driver is manual, and it's nice to have total control, but I miss having that free hand for soda and whatnot. The perfect trans. would be a CVT, but I don't think the technology's up to par yet. While we're on the subject though, I heard a rumor that the right automatic can accelerate better than a manual because of quicker shifting. Can anyone verify this or insubstantiate it?

Posted: Mon Feb 27, 2006 11:19 pm Post subject: Re:longitudinal vs transverse

Forgot to add that I would like to take it to auto-x events on rare occasion, or just enjoy the open road on weekends.

Posted: Tue Feb 28, 2006 9:53 am Post subject: Re:longitudinal vs transverse

Hi, just a thought but in europe Lancia did a version of the Thema called a 8.32 which are going cheap these days. Made in the early 90's it used the Ferrari Mondial set up in the front (FWD) which will give you the power you require with an engine/gearbox package that will fit transverse.
http://www.viva-lancia.com
Best regards

Martin
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Posted: Tue Feb 28, 2006 3:00 pm Post subject: Re:longitudinal vs transverse

Martin,

Great idea. Unfortunately, I'm in the States and I don't even want to think about the cost of importing a car; I'd rather spend it on extras. Plus, James has a good point about the torque steer. I've driven my brother in laws 300+hp FWD Neon, and the torque steer was scary. Maybe it wouldn't be bad with RWD though? Keep the ideas coming.

Nathan

Posted: Tue Feb 28, 2006 8:43 pm Post subject: Re:longitudinal vs transverse

Hi Nathan
UK have not seen Lancia now for nearly 10 years so it is hard to find the Thema 8.32 over here too, shame.
So look at for Audi V6 and V8's with 2WD transaxles (non-Quattro) as this is a good cheap all in one option. V6 Bi-turbo's are getting quite common or save a little and go for a 4.2 V8 there the nuts.

Best regards

Martin
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Posted: Wed Mar 01, 2006 4:03 pm Post subject: Re:longitudinal vs transverse

Thanks Martin. I had an idea from the beginning I'd end up going with the Audi 016 (from A5000) transaxle all along, but I wanted to bounce the transverse and automatic idea out there first. Wich brings me to a second question... I know Quaife makes an LSD for the 016, but can you get it in or modify it to a higher (numerically lower) ratio for a v8 without breaking the bank? The quaife part is expensive enough by itself.

Posted: Wed Mar 01, 2006 4:26 pm Post subject: Re:longitudinal vs transverse

For a Chevy auto transmission that'd take the power of that v8, if built properly, yes it will easily out-accelerate a manual, because there is essentially no lost time of accelerationg for a shift.

You can also get a manual valve body to shift the automatic transmission manually.

That being said, the manual will still give you the advantage in turns. For Chevy V8s this is a good rule of thumb: If it's drag racing or mudding, go automatic, if it's anything else, manual.

Also, if you are going to go turbo, automatic is better there too. (but again, not as good for cornering control)

Reguarding torque steer, that is only a problem on AWD/FWD applications. Torque Steer doesn't effect non-turning wheels (since there is no "steering" there)

So really you need to decide on your primary use for the vehicle. If the primary purpose is sport luxury, and straght-line performance is more important to you than corners, then I'd recommend going with an automatic w/o a manual valve body.

Good luck on your project I'm still trying to decide on a body shape for mine Smile

Posted: Wed Mar 01, 2006 7:01 pm Post subject: Re:longitudinal vs transverse

That's some good information - thanks. Can I assume an automatic w manual valves (paddle shifted - drool) is as good in the corners as pure manual? Don't know what I was thinking about the RWD torque steer thing, but thanks for the reminder.

Could anyone recommend a specific auto box for SBCs so I can compare specs with my manual of choice - the Audi 016? It will probably have to be a transverse not to push the wheelbase out too far, unless there's such a thing as a longitudinal automatic transaxle (probably big $$).

Nathan

Posted: Wed Mar 01, 2006 7:45 pm Post subject: Re:longitudinal vs transverse

Hi Nathan
Nearly all Audi's including FWD 2WD set ups have the engine mounted north/south with the gearbox/transaxle mounted behind the engine. Quattro models have the prop drive coming straight out the rear of the box just like a front engine RWD gearbox. So a Audi 2WD auto would be ideal for mid-mounted longitudinal set up. Some VW Passat's are set up like this too including the 2.5 V6 TDi and 4motion's.

Best regards

Martin
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Posted: Thu Mar 02, 2006 2:53 pm Post subject: Re:longitudinal vs transverse

Ah yes, and I believe many Audis are already set up with "his and hers" shifters. Could I expect the torque rating of these trans to be comparable with their manuals (up to 400 hp)?

Posted: Thu Mar 02, 2006 7:10 pm Post subject: Re:longitudinal vs transverse

The Tiptronic in the A8 fits all upto the 6.0 W12 with 444bhp and 428lb ft in Quattro form but you can remove the rear output shaft housing and plate it over. The Germans like to build there gearboxes to handle twice the input the engine outputs for reliability and they do last twice as long as most products.
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