things to look out for? - Honda Prelude Forum

videogmike · 02-24-2008, 05:26 PM

hey guys, so there's some nice discussion in this board about atts vs lsd

my old car was an SH and it's the only performance oriented car i've ever driven/driven hard/tracked. i had i guess only 3 track days under my belt but i was very confident in it on a road course. anyways you all say that an atts car handles significantly different.

i'm now driving an 07 si with obviously an lsd.

the question is, is it going to react extremely differently than my SH did? do you all have any advice or things to think about/be careful about when i take my si to its first HPDE event?

one interesting thing that is very noticeable that i never noticed in my SH (not sure if it even did this?) is that when going around a turn, like an on ramp it follows the line you point it on very well under acceleration (perfectly normal), but if you let off the gas without changing steering input it cuts in much much tighter.

apologies if this is repost...my searches didn't quite turn up what i was looking for.

Jacques · 02-29-2008, 03:44 PM

Interesting that no one has posted back to you on this one. I don't have any experience with the Si, but there's some things to expect. The Prelude has double wishbone suspension front/rear while the Si has a McPherson front/multi-link rear (similar to the RSX)...the former suspension is considered more ideal (more dynamic when pushed to the limit), but costlier. It also has a smaller rear bar vs. the Prelude's (17mm for the Civic, 23mm for the Prelude). As for the helical LSD, my experience with it is it does have some similarities with the ATTS. Here's what I posted on the lsd vs atts again thread:

Before you can answer what LSD basically does in corners, you'll also need to keep in mind there's two different kinds of LSD. Viscous LSD's are basically speed-based, in which it will adjust when speed increases. Though that may be fine with regular driving where adjustments are minute, in a racing situation it won't aid you as quickly, especially in situations where speed might not be a factor (ie: slow, steady state corners). The Integra Type R, as well as the Quaife, uses a helical LSD, which is torque-actuated, shifting torque to the outer wheel in cornering, and giving equal power when going on the straight line. The execution of the helical in a corner is fairly smooth, almost to the point of being unnoticeable (to me anyways)...but it works well.

ATTS is also torque-actuated, hence the acronym's definition..."Active Torque Transfer System". Though a helical has an advantage in a straight line in terms of power delivery (ATTS doesn't do much, if at all, in a straight line), the system works at its fullest around corners, sending torque to the outer wheel (approx. 80%). Unlike the helical LSD, when driven hard, not to mention mechanical, the ATTS puts its torque out rather abruptly, and does this electronically. It takes some adjusting in driving style if you've never driven an SH hard before, but if done right, you can get into throttle even before you reach the apex and power through all the way to the exit. People that have ridden along, and some that have driven mine, were amazed how balanced it felt, with almost no understeer (a little bit of oversteer, party due to my suspension setup), rotated very much like a RWD car, and how easy throttle response is around corners.

videogmike · 02-29-2008, 08:30 PM

so basically it should feel about the same as my SH and won't do anything weird on me? and very possibly being better than my SH.
just curious as i haven't tracked my Si yet and it will be interesting to do nelson ledges a second time. except this time it will be in an Si instead of my SH.

i knew all about how atts and lsd works, the question was just more of a "will the car react much different."
for example if you get going a little too fast, in the SH, you could just lift the throttle to slow down a little. doing that in my Si won't put me into some kind of throttle lift over steer situation correct? i haven't had much practice/experience w/ handling oversteer.
might have not totaled my prelude if i had :/

Jacques · 03-03-2008, 01:20 AM

I'd work on modulating the throttle, not so much lifting off completely if you go around a turn too fast. You're going to get throttle lift oversteer even with an LSD if you suddenly lift off the the throttle. If you've done any suspension mods on the Si and are able to adjust it, then I'd soften the rear a bit so it wouldn't rotate as easily. Or, either be more conservative around turns ("drive within your comfort level"), brake sooner, and work more on a faster corner exit (my other fave phrase "slow in, fast out")...or learn to left-foot/trail brake.

videogmike · 03-03-2008, 05:01 PM

lol yea, like i said i only had about 3 track days in my SH. but i felt by my 3rd i was pretty fast for the beginner run group considering my prelude was stock and i was passing lots of people. i went to hallett, gateway, and nelson ledges.

glad to know the car is going to drive about the same. i'll just take it way easy the first session or 2 until i get a good feel for it.

Jacques · 03-04-2008, 01:50 PM

Quote:

Originally Posted by videogmike

i went to hallett, gateway, and nelson ledges.

I didn't realize you were at the last three NPM's...I was at Hallett (instructed there), was (and hosted/instructed) at Gateway, but missed Nelson Ledges (the missus and I had a baby that same month).

If you go to the next NPM, see if they will let you run the first couple of sessions in the Beginner group, and when you're comfortable, move up to the Intermediate group. Though you'll have more room to move at that point, I'd still be cautious.