Cruising at 110 MPH in the Coupe

[sptcoupe]

Except for the cold air box, we finally finished up the coupe this weekend (making final exhaust fitment adjustments (no more rattles!!), cleaning up some rust spots on the undercarriage and re-applying undercoating, making heat shields in the engine bay, etc), so I drove it down to Houston in the early hours today before it got to the triple digit temps.

Made the 300 mile trip in 4 hrs, 5mins, with one pit/fuel/coffee stop, for an average speed of about 75 mph, and got 25.7 mpg.

I don’t feel too bad about the MPG, as I spent about 15 straight mins cruising at an indicated 110 MPH, or about 6300 rpms in 5th (see pics). Very comfortable, and those 44 IDFs just purr at that rpm range at steady throttle. Since we have the longer gears in the coupe, the indicated speed is slower than the actual by about 3-4%, so the actual speed may have been about 115 MPH. On the initial run up to speed, I got it to 7300 rpms in fifth, and then for a while, held it steady at 7100 rpms in 5th, with an indicated 123 MPH. Still was pulling, but at about 7000 rpms and up, those carbs are flat out screaming, even at steady throttle, and since I am only temporarily running “lunch box” air filters, it was just too loud to hold for more than a min or so. I just love that banshee wail!

I was also really pleased with the hard acceleration all the way to the top. I dropped into third at about 65 MPH and took it to 7800 rpms. Very quick. Then took it to 7500 rpms in fourth, and 7300 rpms in fifth, before I settled at 7100 rpm for about a mile or so. And it idles like the stock FI spider (maybe better?) @ 800 rpms.

I was glad to see the eng temp and oil pressure were rock solid for that entire high speed run (see pic), and it doesn’t appear to have used a drop of oil. The air temp must have been around 85 +.

Can’t wait to get the cold air box on there and get it back to the dyno for final tuning. There’s a few more HP lurking around somewhere, for sure, as we have not played at all with the igntion or cam timing.

And if any of you turkeys tell my wife about this - well, just don't!

http://i721.photobucket.com/albums/ww21 ... 6-Copy.jpg

http://i721.photobucket.com/albums/ww21 ... 1-0813.jpg

[So Cal Mark]

glad to hear they have laid off all of the Highway Patrol officers in Texas

[spiderrey]

Nice, taking pics at 110 mph. . I know there is still more there. I ran mine with the auto geared rear end and was surprised at the speed it was capable of. The sound was awesome. Luv your car, congrats.

[sptcoupe]

That drive between Dallas and Houston has to be one of the most boring drives around, but the roads are good, really straight, plenty of visibility over long stretches, and very few cops! There is one long stretch (where I let her run for 15 minutes) where traffic routinely moves at 85-90 mph, so I wasn't too noticeable. And it was right after sunrise, so there wasn't anyone around to see. This is the first time in 24 years I have run the coupe with the taller gears, and I have to say that with the right amount of HP and torque, it really does become a more comfortable road car. Not only is it capable of higher speeds, it is also more comfortale and flexible in every day driving circumstances as well.

[spiderrey]

Those gears were great for most drives, but they seemed a bit to tall for twisty mountain roads. I wish we could get some 3.73,s.

[ital]

Hey Jeff, not bad! what taller gears are you running now?? 10/41 or the 10/39??

With my 1608 coupe I max out at 7000 in fifth with the 10/43 gears. I am about to install the 10/39 gears out of a Special T.

[ga.spyder]

It has been so hot in Texas,that all the State Patrol guys were probably in a air conditioned donut shop.Glad to hear you have de-bugged the car! That is awesome.

[sptcoupe]

Running the 10/39s now, and really like it. What I really love with this particular engine is 2nd & 3rd, from 25 MPH to 90. Really a delight. Just relentless in 3rd. But I have some serious concerns with the longevity of the stock tranny!

But, I don't like the Konis all around and a heavy front bar. Still convinced the best set up for the coupe is KYBs in the rear, Konis in the front, rear sway bar, stock front bar, and lowering springs. The heavy bar in front (which I have now replaced with a stock bar) plus the Konis in the front just tighten the front end up, and undo what the addition of a rear bar and lowering springs have done to reduce the built-in understeer in these cars. Konis in the rear seem to tighten it even more. With lowering springs you get out most of the roll, and with the rear bar and Konis in back, it tightens the rear enough to really move it toward neutral. Never have experimented with a spider - but if you lower a coupe, add a rear bar and put Konis back there, you get a sweet handling, relatively neutral car.

Anybody else played with different suspension set ups?

[Redline]

I can only say that I really like my Spax adjustables so far, but everything else is stock (springs, ride height, bars). I need to back them off another click or two, as it's a bit harsh (I'm in the middle setting, so lots of room to experiment), but I love the way they swallow compressions. Really great damping. Seems to also control the body very well. The car feels alert without feeling hyperactive, which is how I wanted it. I'm surprised how well it all works with what should be too much tire (205/60-13 on 7x13 wheels). Anywhere above a crawling speed and steering effort is no problem, and the only time I notice any tramlining is when heavily braking on roads that have been severely channeled by heavy trucks.

I like.

Just wish my motor sounded like yours!