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914World.com _ 914World Garage _ 914 V8 drag race video

Posted by: elocke Sep 22 2005, 08:18 PM

Thanks to Mark Skala and his setup I'm able to post this link.

http://www.rcd-video.com/images/drag-low.mpg

Also he helped me get my car back after spending the night in the NE Dragway parking lot with a missing water pump belt. It either flew off or broke sometime during the run. The right meter under the knee pad indicates 180 (straight up) during the run, but early on the way back I noticed temp gauge pegged and freaked. By the time I pulled over it started to steam. 260 on the mechanical gauge on the manifold! It blew the overflow hose off the filler neck after cutting a slice in the plastic expansion tank cap. I thought for sure I'd cracked a head. Luckily it seems to run fine, but I need to talk to the builder about lurking damage.
Below it my time slip. Bad reaction time and a tranny-saving start on 185's helped only my tranny, unlike an earlier Mustang that delayed things 25 min to clean his off the track.
For some background on the car I think it's in my project post, which I haven't updated in some time but the basics are there. I've been so busy driving it!
Ed

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Posted by: Aaron Cox Sep 22 2005, 08:32 PM

fun!

looked like a nice easy start for 2nd gear....

BTW - stock gears?

Posted by: elocke Sep 22 2005, 08:40 PM

Yes, stock gears. Renegade heavy axels/CV's. Wish I had a 930 box so I wouldn't have to worry, but I need to preserve mine at least until I try autocross.

Posted by: Hammy Sep 22 2005, 08:54 PM

the 901 just isn't the best on acceleration, is it?

Still How did you not piss yourself..

Posted by: Aaron Cox Sep 22 2005, 08:56 PM

QUOTE (Hammy @ Sep 22 2005, 07:54 PM)
the 901 just isn't the best on acceleration, is it?

Still How did you not piss yourself..

its fast if you can spin it to 7 or 8k...

throw some tall gears in that bad boy.....

Posted by: tesserra Sep 22 2005, 09:28 PM

I threw off my water pump belt at my first auto x. Turns out it was not well aligned and continued to have problems until I really got on the alignment issue.
As with you I worried about lurking internal problems the car seemed fine until it blew a head gasket and hydrolocked the motor. IT WAS UGLY, and expensive.
On a more positive note, I don't think any 914 can see the speedometer climb that fast at such high speeds unless it has a V8.
I love to watch speedometer when I downshift to 3rd (4th on normal trans) and floor it.
Good luck and really check carefully the alignment, mine came from Renegade and it was off.

George

Posted by: 914GT Sep 22 2005, 10:11 PM

Ed, that's a cool video clip. I could almost feel the rush like I get driving mine around. I was watching your tach in the video and how it bounces around. Take a look at http://home.earthlink.net/~guy2k/sitebuildercontent/sitebuilderpictures/New%20Tach%20Conversion%20Comparison.wmv of what I'm doing to my car.

Posted by: J P Stein Sep 22 2005, 10:23 PM

So, how do you dampen it?
I have a similar problem.

Posted by: Rand Sep 22 2005, 10:32 PM

Guy!!!!!!!!!!! Stop teasing us!!!

Very nice.

Ok, now, do tell.... how do we get that ultra-responsive tach?

Posted by: 914GT Sep 22 2005, 10:59 PM

I don't mean to hijack Ed's thread here. However I am interested in how much he watches the tach when drag racing. I don't find the modified stock 914 tach all that useful but I do glance at it on occasion. When drag racing there are other things to be watching so is an accurate tach of much value?

About a year ago I spent a lot of time screwing around with different circuits for the 914 tach. I had something that worked much better than the original circuit but it was a pain to make linear, and the old movement has a lot of mass and there's only so much you can do with it. So I found an aftermarket tach and figured out how to transfer its innards into the old case, then recalibrate it for the stock bezel. I'm going to put it in my car tomorrow to test it out. Maybe I can post a new thread later on the results.

Posted by: Hammy Sep 22 2005, 11:23 PM

Guy, please do

Posted by: Mueller Sep 22 2005, 11:41 PM

QUOTE
Ok, now, do tell.... how do we get that ultra-responsive tach?

simple, install a fast rev'ing V8 engine with plenty of torque seems pretty simple to me, hahahaha

knowing the rpms while doing the 1/4 is very important to ensure you shift at the optimal point...the serious guys install a tach with a bright light that'll flash at a pre-determined rpm...of course I'm just guessing that he was overly watchful to make sure he didn't over-rev and blow something up

Posted by: rick 918-S Sep 23 2005, 04:39 AM

Stupid dial up! Can't wait to get home!

Posted by: John2kx Sep 23 2005, 05:23 AM

Ed,

Nice video! North Hollywood converted my stock tach.........no bouncing needle.

John

Posted by: dan10101 Sep 23 2005, 07:28 AM

What kind of v8 do you have in it?

I think I'll G tech my car when I get it tuned. (though I dont like taking it over 100 very often)

I must say you shift well... My car clunks into gears... lol

Andrew

Posted by: Root_Werks Sep 23 2005, 09:07 AM

That was a cool video! Thanks for sharing that!

Posted by: bd1308 Sep 23 2005, 09:14 AM

sure gives me a new adoration for the V8 though....sounds pretty

Posted by: bondo Sep 23 2005, 09:18 AM

QUOTE (Mueller @ Sep 22 2005, 10:41 PM)

QUOTE
Ok, now, do tell.... how do we get that ultra-responsive tach?

simple, install a fast rev'ing V8 engine with plenty of torque seems pretty simple to me, hahahaha

knowing the rpms while doing the 1/4 is very important to ensure you shift at the optimal point...the serious guys install a tach with a bright light that'll flash at a pre-determined rpm...of course I'm just guessing that he was overly watchful to make sure he didn't over-rev and blow something up

Can you really over-rev a V8? In my experience (stock V8s without race cams and such) The power drops off enough before the redline that it'd feel unnatural to run it all the way up there. A missed shift could still do it I guess.

Posted by: TeeBee Sep 23 2005, 09:23 AM

Dat's me big brudda's car! Go, Ed!

Now as soon as I put an LS1 into my Miata, we're going head-to-head!

teebee

Posted by: Mueller Sep 23 2005, 09:36 AM

QUOTE (bondo @ Sep 23 2005, 08:18 AM)
Can you really over-rev a V8? In my experience (stock V8s without race cams and such) The power drops off enough before the redline that it'd feel unnatural to run it all the way up there. A missed shift could still do it I guess.

you can over-rev a lawn mower engine (BTDT, got the broken crank to prove it, hahahaha)

there are 2 types of over-revving the motor:

1) the most obvious of taking the motor past it's redline which could cause damage

2) the more important one for drag racing, keeping the motor in it's optimal rpm range...if you know that when you shift there is a 500rpm difference in your gear ratios, you don't want to shift too early or too late..if the motor can safely rev to 8000, yet the torque falls flat at 7000, then you get no benifit taking it to 8K, you are better off shifting early

Posted by: Andyrew Sep 23 2005, 10:01 AM

I over revved my car once...

That was when my throttle cable was sticking on my clutch cable...

clutch went in.. throttle stayed on... I think I hit 7k.

Andrew

Posted by: marks914 Sep 23 2005, 10:13 AM

Sweet video. I would definately do the tall gears, much longer winding out of the engine. Brad Mayeur did mine and I love it.
Here is a chart with the new gearing.
Mark

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Posted by: elocke Sep 23 2005, 11:25 AM

Engine's a '66 283, bored .03. The bottom of the bores appear to be factory cast with clearance for the 327 crank so it s/b good to go up to 4" bore. Moderate cam, 1-plane Weiland manifold w/borrowed holley 750 4bbl. Normally I run a 500 cfm 2bbl holley. I was hoping to try diff't timing and maybe jets but 1 run was still very thrilling. Below are the graphs of my engine and stock gearing w/185/70 15's. I was considering shifting into 5th but the finish line was so close. Maybe with a better start I could have used a torque boost with a shift to 5th?
This was the 1st time I've ever even been to a race track. I was pretty much just watching the tach during the race. I've used it before to shift into 3rd at 6K on the street, and have done 90 in 4th before.
What's a G-tech? Chassis dyno?
That's a cool tach video. Is the good one retrofitted with guts from a diff't tach or modified stock?
My builder said I appear to have "made tea, not coffee". My tea was ready when it started steaming. Coffee is what the dipstick could have looked like. He suggests I check: 1. inside valve covers for condensation/coffee. 2. cooling system pressure check. 3. verify head torques using proper sequence. If there are no findings I may be OK. Otherwise pull heads, check for straightness and install new gaskets. He says he's seen 260 on circle track cars w/ no anti-freeze lap after lap!!

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Posted by: Dr. Roger Sep 23 2005, 12:26 PM

To figure out when to change gears....

Chart your torque RPM band.

Note RPM drop during gear changes. (let's say 2K RPM's per shift)

Calculate max torque over a 2K RPM range. (let's say your torque rises up at about 2500 RPM's and stays fairly flat till 5500 RPM's then drops off)

Max torque is noted to be at the 4K RPM range

So to keep max acceleration you would want to keep the engine in the max torque range.

This calculates your shift point to be about 5K PRM's.

Knowing that when you shift your torques is already dropping off. The RPM's will drop 2K RPM's, taking you back to the point where max torque is. you will want to bring your RPM's to 5K RPM's then shifting will bring the RPM's back down to 3K RPM's to go through the max torque range again, and again, and again.

V8's really are great.

I'm scared of mine. I've got the flipped H gear and highway cruising is almost too much confidence building for me to take.