When I was much younger and stupid, I was doing over 140 on I-5 back in the late 80's. Same car but with a 2.7, Weber's, headers and stock trans. Nice long straight aways, playing tag with the Mustangs. The stock Mustangs could do around 120 back then, but there was a Saleen Mustang that could keep up with me. The highway patrol arrested one of the drivers of the stock 5.0 Mustang, while me and the Saleen Mustang watched from a rest stop.

Did over 100 in a 914-6 on the high banks of Daytona as a passeger back in 1970 or 1971 (dont' remember exact date) and have my little card showing I"m a member of the 100 mph club to prove it!

Did some pretty stupid things in my 914's over the years, but probably never was much over 100...

("a friend" did average over 100 with a friend on Oklahoma Turnpike many years ago going back to IA in a modded 914-6 from the old Tulsa tech sessions put on by War Bonnett region. We "lost" our ticket because it had the time stamped on it when we started...)

This is an interesting thread.
Interesting for what it's not mentioning.
In past threads, I've read that the 914 can get pretty twitchy at triple digits. And very recently (after years of work) I felt mine was safe enough to take into the triples. I found it to be quite twitchy myself. This is going to be my primary track car and will certainly be getting into those speeds and after having consulted some track pals and a mechanic that's familiar with my local track, I've decided to build a splitter out of ABS. I'm hoping that this will help get some downforce on the front end and settle things down some.
Anyone else experience this "twitchy" feel at high speed and build a splitter?

Lets see your rear end, I've been to 130 many, many times as thats the top of third for me in my current configuration. I feel the front is more twitchy than the rear at this point and thats probably all alignment. I know my downforce is low at the rear and my big tires probably help my mechanical grip. I do plan to add a diffuser later.


You can see how high I cut my rear bumper in an attempt at gaining clean airflow under the car.

There's more to consider than meets the eye...without balance it will not work well. Adding a splitter in and of itself is not a solution - especially on a teener. If you are going to consistently drive fast (in a 914), below are the three most important things to consider (and in this order). If you install and get all of these correct - you are good. No need for a diffuser at that point. Just my experience and opinion...

PS: If you cannot literally STAND 100% on your splitter - you are wasting your time. But I do not think you should install one anyway (first anyhow). It needs to be able to support 250+ pounds - not so sure ABS is going to get you there. Don't put it on - at least first - address in order below and test each time.

1) Alignment
2) Rear Wing
3) Splitter

T

One (four wheel with corner balancing) and two already done, see image for rear wing.
ABS material, 3/16 (back to back). The upper shelf out about 3", the lower shelf adjustable for 5" total. The upper shelf will extend back to about centerline of the front wheels of the tub.
This is a material and configuration other people are using at my local track (SUmmit Point).
I think my rear wing is actually causing the imbalance.
Click to view attachment

Ok. Here is what I have...

1) That is not a wing...that is a rear spoiler. It is doing nothing but for looks. Nothing.

2) A steel frame needs to be made that bolts to the suspension cross-member in the rear and the front torsion bar caps in the front. My diagram is attached below...

3) You can use the ABS but skin in on (at least) one side with 14 gauge stainless sheet - the whole splitter. Do not worry about adding weight...

4) Do not do any of this until a proper wing is installed...this is a major PITA - just being honest. I have attached a couple pictures below of my set-up - this took some time to figure out.

5) My experience (and screw-ups) have taught me not having enough negative toe in the rear causing high-speed instability. Adjust for a minimum of .100 per side and up to .200 if you have more than 400 hp/tq.

6) Good luck!

Tony

Splitter Detail
Click to view attachment

Upright Detail
Click to view attachment

Wing Strut Detail
Click to view attachment

Upright core and strut
Click to view attachment

Splitter (Carbon, Kevlar with honeycomb core) with embedded aluminum hardpoints
Click to view attachment

Car on track...

https://www.youtube.com/watch?v=5x4hRTzKFXw

As a matter of record...when I locked the front up in the above video - I did not have the splitter on the car. It was fractured earlier in the day. It broke at 160 and caused allot of trouble. I ran without it the remainder of the weekend (mistake really) - thus the lock up due no front (or reduced) downforce. It REALLY does matter...

Tony

I tried ABS sheet plastic before. Too heavy and too flexible.
You should instead use a carbon sandwich with honeycomb core; much lighter and stiffer. $$$

dragonplate.com

Good data.
Thanks

I'd like to do it in something that was designed for fast.

Since "dreaming" is now allowed...why stop there? The problem for me is at 6'6" and 230 lbs I could barely get my big toe in the F1 car (not that it matters of course)!

T




Click to view attachment

Not in the same universe as the other two but...it is mine and the most amazing car I have driven on track.
Click to view attachment

That's James Dean's crash. A Ford made a left turn across his path and he collided with it. He was reportedly driving about 85mph.

About 128 and change at Thunderhill according to GPS. That was with the 4 cylinder borrowed Dwight Mitchell motor that is destined for Jim Dupree's car...

Thw 962 is not mine but I did sit in it and make vroom vroom noises.

the front bumper profile would almost negate the effect of a 4" splitter on that white car

6100 rpm, 5th gear, stock 901 transmission gearing, 205-15 tires with a "stock" 4 cylinder 2 liter.



(with a little boost)

That was fast for a 914 but I've been much faster in a drag boat.

I've been close to 150 in mine by the end of the front straight, but that was a ton of front to rear bumper drafting of a 993 and my engine is, um, not stock (84mm crank and 103mm pistons, dual Weber's), for 138hp at rear wheel. Likely had a hell of a tail wind, as I've not seen over 135ish since.

My Speedo is usually taped over at the track, but telemetry is always fun to look at after.

That's pretty impressive. I have a 225whp Honda Civic 6-speed that I raced at Daytona, and I was only able to attain 149.3 mph across the tri-oval, while in the draft (per GPS-based data acq).


Amen. I don't look 'til after. I don't want to know.