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Prepared Car Support Group

32K views 362 replies 23 participants last post by  XHead 
#1 · (Edited)
There is definitely an increase in people BUILDING MR2's for the Prepared classes. XHead (Steve) has his car running, and competing. The rest of us, well, we just aren't getting them out to National Tours, or Nationals.

And admittedly, I'm not one really to talk. So here is our support group to kick, cajole, and convince each other to get some Prepared cars done and racing. :smile:

Here is the DP class roll:
verno-dub: where is your build thread?
zipty842: http://mr2oc.com/showthread.php?t=330735
myself: http://mr2oc.com/showthread.php?t=227103

And the only fully ready to go car:
XHead: http://mr2oc.com/showthread.php?t=320185
 
#27 · (Edited)
Back window replaced with Lexan: http://mr2oc.com/showthread.php?t=336929

Removing the rear window took 15 minutes, maybe: gently push on the top of the window and prior upper rubber seal out.

I reshaped the Lexan I used in v1.0 so that it would fit in the OEM window molding, that took me maybe 20 minutes. I used a dremel, with the cutting bit, and taped the lexan to the OWM back window, then carefully followed the contour of the back window. You can prevent chips/knicks in the glass by taping the edge you are following

Reinstall took about 90minutes: sonuva... it was a PITA. I can't say whether it was that the lexan is a little bit thicker, or if the shape of the window still wasn't quite right. But it went in eventually, by walking a thin screwdriver around the seal, I did use some 303 protectant to make things slide a bit. One corner is a little wrinkled but it is on the inside.
 
#29 ·
OK, you asked.

The StuporCrapp muffler and pipe. The supertrapp is awful. Will kill your top end power. The pipe is too short to make torque.

Get a real muffler. This is the prototype (test version) of the system I put on my car. That's a Walker DynoMax UltraFlo muffler. The length is tuned to make torque.





-Steve
 
#37 ·
heh, I elbowed my sunroof last friday getting in the car to get it off of the trailer <_<
good thing its safety glass, but I dont wanna pull it out yet to do a couple of things due to the crazy weather we have. I'm supposed to be getting a stall in the same building my dad's shop is, but the guy doesn't seem to want to clean it out.
I hope to have my lexan made up sometime next week.
 
#41 ·
The front bumper can support itself using the radiator support and fenders. There is strips of studs that connect everything. The rear bumper will require brackets to be made.
i personally left my rear bumper off.
 
#42 · (Edited)
zipty842 said:
The front bumper can support itself using the radiator support and fenders. There is strips of studs that connect everything. The rear bumper will require brackets to be made.
i personally left my rear bumper off.
I agree regarding the front bumper. Once it is gutted it holds pretty well to the upper radiator support, and the fenders. See here: http://www.pbase.com/mtb_zack/image/109738887

On V1.0 (my first chassis) I gutted the bumper, welded in two short L bars and supported the rear bumper with some hood pins, and Zip ties. I planned on filling it with foam. You can see here: http://www.pbase.com/mtb_zack/image/98010323

I am thinking of another sloution now for V2.0, the hardtop.
 
#44 ·
im really interested in your feedback in regards to these spring rates. I seem to be having a little more understeer than id like with the 600front/350/375/400rear set up. Id like to try and up the rate to 450lbs/in in the rear, but im weary on leaving the front rates at 600lbs/in, so im going to wait until I get feed back from you guys. Maybe its just me.
 
#45 ·
Verno-dub; understeer??? You shouldn't be getting understeer. Send me an email so we can talk about what's going on.

I made a set of brackets for my rear bumper from aluminum angle. Light, cheap, easy and holds the bumper in place nicely. I hated the way the car looked without the rear bumper cover.

-Steve
 
#47 · (Edited)
Tonight, I plan on cutting and installing the Lexan for the rear quarter windows. For now we will re-do the alignment, make sure the brakes are bled well, tighten everything down properly, and go racing in two weeks.

I have lots of aluminum sheeting to build the rear deck, and clean up the interior with once the next couple of events shake out the car. I have also order a few carbon fiber sheet samples to be sent to me. I can't help it, I love the stuff.

sliverstorm said:
Have you played with the settings on your dampers? I've been fooling around with my konis, and a half turn makes all the difference in the world when it comes to how the thing drives.
Yes, I had done some testing on well worn asphalt. I'll say that there is a definite corner-off understeer that develops with excessive rebound damping in the front.

However, take that piece of data with the fact I need to completely cure my bumpsteer issues. :p

verno-dub said:
im really interested in your feedback in regards to these spring rates. I seem to be having a little more understeer than id like with the 600front/350/375/400rear set up. Id like to try and up the rate to 450lbs/in in the rear, but im weary on leaving the front rates at 600lbs/in, so im going to wait until I get feed back from you guys. Maybe its just me.
I can't report any understeer that I didn't semi-knowingly create. If anything the car might be a little loose transitionally, I never got to test in a slalom, just a never-ending circle rights (or lefts) around our block in the industrial complex.
 
#49 ·
verno-dub said:
im really interested in your feedback in regards to these spring rates. I seem to be having a little more understeer than id like with the 600front/350/375/400rear set up. Id like to try and up the rate to 450lbs/in in the rear, but im weary on leaving the front rates at 600lbs/in, so im going to wait until I get feed back from you guys. Maybe its just me.
Guys could you please share your findings here.. this is such a great post, and the suspense is killing me..

thanks
 
#50 · (Edited)
Shane Bawa said:
Guys could you please share your findings here.. this is such a great post, and the suspense is killing me..

thanks
Suspense? You mean suspension? :p

DISCLAIMER - My 'findings' are based on driving a car with an oil leak for 2-3 hours figuring out how I want it to handle. The notes are "as best as I can recollect". Although some of the numbers I know are dead on correct.

The "tester" car (my V1.0 car):
It weighed 1857 on that day, plus 200 pounds of me. 57% rear weight, 43% front, and corner weights were an atrocious 53/47, when I was in the car. (I have a picture somewhere of the scale read out) I never measured the ride height.

Suspension set up: 600F/Koni Yellows, 450R/Koni RACE. I had about 2-2.5-3 (?) degrees of camber front, about 1.5 in the rear, and toe was 1/8th out in the front and 1/8th in for the rear. (I would say that is way too much camber/toe for the front) The test "course" was rectangular block (4 - 90 degree turns) about 1/10 mile in total length, with well worn but "sharp" asphalt, with large aggregate (pebbles/rocks).

I had talked with Gordon Benson at Koni, and he recommended a couple of tests to set rebound damping using these. I will also state that "testing" a car to set it up can be tedious. Ideally you'd have a data logger that told you what was actually going on, because the butt-dyno is not that good.

The Protocol:
Drive the car at a set speed a couple times around your test course (closed site/street) in both directions. Then do it at full soft and full firm to notice the difference at the end you are setting. Make sure you are using inputs like you would on an autocross course.

For the fronts: Start at full soft (counter clockwise) and add damping in 1/4 turn increments until the car pushes transitionally (Turn-in/apex off). Then soften it about 1/8-1/4 turn and retest.

For the rears: Start at full firm (clockwise) and reduce damping in 1/4 turn increments until the car until the car pushes transitionally (Turn-in/apex off).

Repeat again for front and rear. (I stopped here due to my lil oil problem/church starting across the street)
Repeat process slowing into turns and accelerating out. Then repeat process driving at 90-100% concentration.

My Impressions:

My car had some mild bumpsteer in the front and probably the rear. That is #1 on my to-do list after the car actually survives an event.

Obviously, the yellows are a little over matched for the 600 springs on a bumpy surface. I had to go a little firmer (1 full turn) than I expected based (1/4-1/2 turn) on my email conversation with Gordon.

I liked the rear spring rate for the steady state turns of my "course". But it may make the car oversteer too much in slaloms, I don't know.

Once I actually get to an event, and get the car aligned the way I think I like, I'll go back and reset the rebound damping (only thing controllable with the single adjustable shocks)
 
#51 · (Edited)
Hey everyone,
I bought a '85 DP last year and have been entering it in local auto-x and taking it to track days at VIR. The car has been slowly transitioning its way from street to "prepared" thru about three owners. It's still a long way off. So far it has the interior stripped, racing seats, auto power cage, Tokico adjustibles, Eibach lowering springs, MSD ignition, 5 point belts, HKS high lift cams, Flowmaster muffler, Greddy Emamage blue piggyback, and Hoosier A6 or Toyo Proxes RA1 205x50x15. I also moved the battery up front.
Next step is to change suspension to Steve's recommended set up, and get '87 brakes. Glad to find this sticky. I have lots of questions for my next post. :) Tried to send a picture from photobucket but it didn't work. I'll try again later.
David
 
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