pix
FORDMUSCLE.com
More Project GMII Articles
Testing the Mac Prochamber
12 Seconds and Beyond
Braced For Action
Powershifting! GMII hits new lows!
Bracket Racing Update
Testing the C&L 76mm Mass Air Meter on GM
Introduction to GMI
When we last reported on my daily driver 5.0 it was running 14.3's with an AOD+shift kit, stock 3.27 gears, underdrive pulleys with a short belt and a set of 1.72 ratio roller rockers. The plan was to improve on the current combo's best ET with some practice, cooler air and stickier tires than the Pirelli P4000 radials. Since then quite a bit has happened to our '92 LX Mustang, so we'll just go through it chronologically in this article.

We installed a used set of McReary American Racer dirt track tires on a pair of obligatory"ten-hole" wheels. The dirt track crowd quits using these tires after each race night, but plenty of tread is left for us cash-strapped drag racers. We also installed a new C&L 76mm Mass Air Meter kit (see our testing article) in place of the stock meter and corrugated rubber inlet. With better grip in hand it was back to the track. Running 14psi of air pressure, a good burnout was followed by a launch off the brake at 1200rpm. The previous best 60 foot, on radials, had been a 2.15 seconds. Typical 60 foots were in the 2.2x range. Now the car was launching with consistent 2.15 to 2.20's even with poor track surface prep. ET's dropped to as low as 14.21 seconds at 97.9mph - about a tenth improvement with the tires.

The stock stall converter was limiting the launch rpm so we could not full take advantage of the improved traction. We discussed installing a higher stall converter. But decided before making any other changes the most important piece of the racing combo needed to be improved, in other words, the skill of the driver! With decent tires and a hard shifting automatic the local bracket races were calling…

Going Bracket Racin'
Sacramento Raceway Park runs Wednesday Night Fun Drags throughout most of the year. It is a bracket-racing format, which means any car can win a race regardless of how fast it is. The importance is on driving your car consistently and reacting to the starting lights at the precise moment. We've see VW busses with 20 second dial-ins head up against ten second turbo Grand Nationals... and win! To learn more about bracket racing, visit the Staging Light.

With our new staff photographer, Geoff Langley, we headed to the track. The single most important part of winning bracket races is consistency. If the driver and car can run the same way every race then wins are almost assured. This would be the first time I raced an automatic in direct competition. If you are serious about bracket racing, drive an automatic! I really enjoyed not worrying about missing shifts and being able to just concentrate on good starts and hitting my shift points.

 
1st bracket night summary-
After bolting on tires, swapping belts and emptying the hatch I ran 1 time trial with an ET of 14.424 at 97.05mph. I used 14.42 for my dial in. As I waited for the elimination's to start I worked on how to be consistent on my launches. I decided to actually count down the yellow lights out loud every time to insure a good reaction time. It sounds a little hokey but it worked for me. As long as you stick to a routine you can be more consistent. I also said a little phrase as I pulled up to the burnout box that has become my mantra and helps calm the adrenaline driven nerves- "Launch on 3, shift on 5!"- meaning the third light and 5000 rpm. After a mild burnout I staged- barely tripping the second yellow staging light. Again- I would stage this way all night.

Run by Run Notes
1st run- My competitor had a 14.5 dial in to my 14.45. I foot braked the car with the stall converter at 1000rpm and launched as I said "3!" and the third yellow lit. My Reaction time (RT)- .702 to my competitors 1.088!
Even though he launched first my RT was better than his .05 start advantage and I was able to get in front of him and stay there the length of the track. I let off the throttle at the end to insure not breaking out and won easily with a 15.209 at 72.84mph to his 14.934 at 89.72mph.

2nd run- Same start routine and mantra! His dial-in-12.65 so I launched first. My RT- .567 to his .440-(.500 is perfect.) He went too soon and red lit! It gives you the win light immediately so I knew I had won and just pushed hard without worrying about a breakout. I ran a 14.498 at 97.08mph to his 12.665 at 113.06mph. He was closer to his dial-in and would have won if not for the start. Pheww!

3rd run-The temperature was dropping so I dialed in at 14.40 to my opponents 13.70. I left first with a .504 RT, almost perfect! He only pulled a .908 so I was able to stay ahead easily and let off at the line. I ran a 14.769 at 85.93mph to his 13.906 at 101.03mph. Win #3!

4th run-With a shorter cool down I dialed in a 14.42 with a 16.93 in the next lane. For the first time I would be chasing my opponent. He launched first and I waited for my lights to drop. He hit a .549 RT, which is good- but I was able to hit a .516 RT, which is even better! I was able to pass him at the top of the track and let off as I crossed the line and ran a 14.53 at 92.22mph to his 17.02 at 80.55mph. Win #4!

5th run- I kept my dial-in and staged next to a '72 Torino GT with a warmed up 460 and a stick. She (yes, she!) dialed in at 13.45. I found out later that she was a bracket regular and was very good. I launched on the third light and she followed almost a second later. I had a .582 RT but she hit a .544. Uh-oh. She just caught me at the finish line for a 13.512 at 95.71mph to my 14.489 at 95.46mph. Damn! At least I made it to the finals first time out (and lost to a cool Ford.) With a class win so close I could taste it I knew I would have to try again the following week.

 
2nd bracket night summary- Bringing home the trophy!
With no changes except for impending bad weather we returned to SRP to try again. If you are wondering about the ET's not being as quick as our previous best times, remember, no ice was put on the intake since the time in the lanes gets shorter as the field gets cut in half each race. This would make it harder to stay consistent. The incoming weather system would also have an effect on ET's. Try to minimize any variables. With tires on and the belt changed we prepared for eliminations with two time trials and recorded a best ET of 14.45.

Run by Run Notes

1st run- My dial-in- 14.45 to his 14.50. I again followed my routine and said my mantra and counted down the lights out loud. I hit a .747 RT to his 1.055. Lucky for me I was racing a rookie. I got out first with the better reaction but he went past me at ½ track and just kept on trucking! He broke out in a big way- running a 13.76 on his 14.50 dial in. I ran a 14.514 at 97.29mph. He was more interested running a best ever ET than winning races. Lucky for me…

2nd run- Changed my dial in as the clouds were rolling in and the pressure was dropping. I saw another racer with a weather station so I began listening to his conversation with his friends. I dialed in at 14.48 to a 14.00 in the next lane. I left first and cut a good .546 RT to his .880. I let off right at the line but, once again, an over eager racer broke out. He ran a 13.882 at 106.2mph(!) to my 14.595 at 94.94mph. Win #2.

3rd run- Kept my dial-in (should have changed it) and the next lane posted a 13.00. I started first with a .577 RT. My opponent had to wait almost 1.5 seconds for his light and over reacted with a .282 RT- red light! I had a lot of spin on that run so I only could muster a 14.60 at 97.35mph to his 13.326 at 104.15mph. Lady Luck was in my passenger seat!

4th run- I upped my dial-in to 14.50 versus a 13.65. Again I launched first and finally cut a great light- .507! The other car could only hit a .742 and could not run me down! I let off at the line and ran a 14.74 at 86.93mph to his 13.78 at 102.43mph. Win #4!

5th run- A bye run. There were three cars left in my class and one car had already run by himself once so I flipped a coin with the other driver and won the toss! The track official asked me if I wanted to wait for the final round or run alone. I chose to make a run to insure I had an accurate dial-in for the final. I ran a 14.638 at 95.967. The track was getting worse and the tires were spinning on the launch and the atmospheric pressure was still dropping with the incoming front, robbing horsepower. I had my new dial-in.

6th run- I was up against a new Dodge Ram truck with a 16.50 dial-in. I changed mine to 14.60. We staged and he launched first and I waited. It is really hard sitting for almost 2 seconds while your opponent runs down the track. I counted down the lights and launched on "Three!" Again the tires spun but I cut a good .534 RT versus a lackluster .761. I passed the big truck after ½ track and made sure I was clearly out front and hit the brakes at the finish line. I won! The win lights went on in my lane and I was shouting and laughing the length of the return road. I had run a 14.910 at 85.24mph to his 16.768 at 81.10mph. Geoff and I went up to the tower to collect the trophy. What an awesome night!

 

To shave weight we shrunk Jim down to under 5 ft. The results were astonishing -three tenths and a bracket trophy!

With a nice trophy and a handful "WIN" imprinted time slips, discussions began again on the future of GMII. The car was impressively consistent in the brackets but 14's were not anywhere near fast enough for this driver. The quest for 13's had us talking about the new heads, converter and gears again as well as changing to an electric fan and upgrading the stock exhaust (past the shorty headers.) I liked the idea of the fan and exhaust upgrades since they could be accomplished in the driveway by a single person (namely me!) and would nicely compliment the heads when they were installed. So, that was the plan, and at this point said plans went quietly out the window…

 
Shop at Amazon.com
 

Gears Gears Gears
The first divergence occurred when this author jumped at the chance to document the installation of a set of 3.73 gears and rebuilding the Traction Loc in the 100k-mile young, 8.8 inch rear. The work was completed very professionally at West Coast Differential. Look for a complete write-up on the process, soon. The car feels much better on the highway, is far quieter and OD is actually far more useful as you can accelerate without the need to downshift. At 70mph the engine is ticking over at only 2200 rpm. These cars should have come stock with these gears (or at least have been a factory option). Once the initial break-in period was completed it was back to the track. Following the same routine for the launches gave similar 60 foots with a rare 2.10 once or twice. A new best ET of 14.06 seconds was attained. Sooo close to that elusive 13.9x! Again we discussed the plan. And, again, the universe had its' own ideas…

"I'm a dead AOD."

Bye Bye AOD, Hello T5
During a return trip from the airport it was a pleasure to push GM II hard on the long on-ramp to the interstate and feel the positive upshifts coupled with the authoritative bark from the rear tires. A daily driver that is actually fun to drive can really make you smile. Ten miles later the smile quickly disappeared as the rpm's started to climb up the tach on their own accord. Shifting back to Drive stopped the climb but meant that at 65 mph the engine was turning 3500 rpm. One more try at overdrive yielded the same results. The OD band was gone. Luckily it was Friday afternoon, which meant I had the weekend to find a fix. The car had to be running by Monday.

After considering a junkyard AOD swap and the inherent gamble it represented I decided to go with the cheapest and most reliable answer. I would take the new T5Z, Centerforce II clutch, and B&M Ripper shifter out of my wounded '65 Mustang and install it all in GMII. The clutch pedal and harness were obtained from a 4 cyl. Mustang at the local wrecking yard. A spare flywheel from a friend, and use of his shop and rack, would have the car back in action without excessive cost. (See our AOD to T5 conversion article)

The first word to come to mind during the test drive is, "Wow!" The car felt so much stronger and quicker with the manual transmission. Breaking the tires loose was now very easy. Rain and wet roads are now cause for caution when accelerating. The T5Z coupled with the 3.73 gears will easily spin the radial tires if the roads are wet and can lead to fish tailing and loss of control.

T5 Test and Tune
With a weeks worth of shifting practice it was time to go back to the track. Launching with a clutch and stick takes more dexterity than with an automatic. I was not too concerned about lack of skill since I had raced my '65 many times with the same transmission! The problem I encountered was that the clutch engagement was quite different due to the fact that the early Mustang used a solid clutch linkage (a "Z" bar) and the late model uses a cable linkage. It does not sound like a big difference but the feel is quite different and I had to unlearn the launch technique I used with the other car. I would either spin the tires or have a serious bog off the line. I could not find a happy compromise. Even with the launch problems I was able to break into the 13's on a tire-spinning launch the first night out. (SEE MPG) After a good hour of icing the intake, GMII ran a 13.974 at 99.17mph on a 2.13 60 ft. in the cool evening air! The usual mods were in place. Changing tire pressure and launch RPM up to 4500 did not help. No combination would give a clean launch. I took GMII home happy with the new best ET but baffled by the starting line antics. I had seen a best ever 60 ft of 2.103 but the bog on that run held the ET back to a 14.09. Something was amiss.

After several internal debates here at F/M and some public ones on the Internet I took GMII back to the track to try and solve the launch equation. The first step was to work on only a single variable until the 60 ft. could not be improved any further and was consistent. This is a cardinal rule of any type of motor sports and is often overlooked in the heat of battle or the excitement caused by the potential of new parts. I had definitely succumbed to the second behavior. This time I picked a single launch rpm- 3500, and only varied the pressure in the American Racer's. I started at 15psi and bogged hard. I raised pressure until the car would not bog and had a good 60 ft. of 2.07 and ET of 13.939 at 99.999mph. Tire pressure was now at 19psi and there was a small amount of spin on the launch. Greedy for more on the last run I dropped pressure back to 16psi and launched at 4700. I hit the throttle sooner than I intended, with the clutch pedal only about 1/3 of the way thru it's travel. The car hooked hard! I was amazed to see a 1.89 60 ft. flash on the boards and hit the rev limiter (6200rpm) before I could shift. I was so shocked I managed to miss 4th gear entirely and ruin my best run, ever. Oh, well, at least I had the missing part of the launch puzzle. Driver error! I was still launching the car like it was my '65. I needed to launch the way this car needed- not the way I was used to doing. Light was beginning to dawn. This little green 5.0 had a LOT left in it. I just needed to learn how to drive it.

 
More Test and Tune
The last two track days this last Fall were simply outstanding. The cold, dry air and driver education combined to push GMII much faster and quicker then I ever hoped for in this nearly stock form. I had read about other 5.0's dipping deep into the 13's with similar or even less mods on the impetus of excellent driving combined with excellent traction. I never thought I could do the same. I thought our F/M readers might like to see my personal notes following those two days and share my excitement at having shaved off so much ET by simply driving more skillfully.
 

11/17/01--------------------------------------------------------------------------------
"Awesome day at the track! I previously asked if I could get to 13.5's w/ a couple more mods and now the answer is a resounding -YES! Knew that some decent driving could lower it, but not this much! Mid 70's by the end of the day.
1st run-
Launch 4500rpm, 19psi, shift at 5000rpm.

60ft- 1.97
ET- 13.875 @ 98.67mph

Nice improvement.

2nd-
4500rpm launch, 18psi- shift at 5200rpm
60ft- 2.101- bog
ET- 13.984 @ 99.476mph -seems to like more rpm.

3rd-(actually last run) got greedy, 17 psi and 5000rpm launch- spun.
60 ft- 2.219
ET- 13.912 @ 100.7mph shifted at 5500rpm- likes it!

Best run- launch at 4500rpm, 18psi, shifted at 5300rpm.

60ft- 1.937
I2- 5.613
I3- 8.708 @ 79.873
I4- 11.370
ET- 13.636 @ 100.486
WOOO HOOOO!!! Cannot friggen believe it! Talk about exceeding my goal of a 13.7x!!! An electric fan and exhaust and 13.5's, here I come!
Mod's- C&L 76mm MAF w/ tube, 1.72 rockers (both mods netted nothing when car was an AOD), Flowtech shorty headers- rest of exh. stock, 3.73's. Ran on the American Racer dirt track tires. Not bad for a 101k 5.0, eh?
Chirag was there w/ Project 11.99 ('67Stang), and Victor w/ Project 460 (a '69 Mach 1 w/ crate 460) ran 11.08. Chirag almost hit the wall after spinning thru some water or oil on the track and still hit a 12.65 w/ a best of 12.53 with the car detuned for street driving. Enough chatter- need to go get another Coronita..."


That was a lot of fun (note all runs in the 13's!) and I realized that with the T5Z the car responded to the higher shift points with more mph. I would use this knowledge to good effect on the last track day of 2001-


12/15/01------------------------------------------------------------------------------------

"Excellent day for racing! Not a lot of cars and perfect, cool (50*) weather. Once again I was surprised by the performance of my 103kmi. 5.0!

Run 1 (no changes from last week)
All shifts at 5500
14.5 psi, 4.5k launch, iced intake
60ft.- 1.997 some spin
ET- 13.638 @ 100.725

Run 2
13.5psi, same launch, power shifted 3-4!
60ft.- 1.981 slight bog
ET- 13.599 @ 101.194 Yeah, Baby!

Run 3
13psi, iced for an hour (sat in lanes), 5mph tail wind, 4.5k Launch
60ft.- 1.938 slight spin
ET- 13.509 @ 102.026!!! Holy Flyin' Bat Crap, Batman!!!

Run 4
stepped on brake in first 60 feet, don't ask me why. Power shift 3-4.
60ft.- 2.183
ET- 13.876 @ 100.521

Run 5
13.5psi, 4.5k launch
60ft.- 1.938 deja vu, slight bog
ET 13.667 @ 100.14

Run 6- Take No Prisoners!
13psi, 4.7k Launch
60ft.- 1.914 some spin
ET- 13.500! @ 100.896 YEEESSS!!!
Even power shifted a little early 3-4 (5.2k) I was so stoked by the 60 ft and clean shifts. Still stock- fan+clutch, exhaust from cat pipe- back!

 
Motor is still basically stock - only mods are a C&L MAF and 1.7 rockers.

Well, there you have it! A pair of 13.5's and one 102mph! I am still finding it hard to believe. I am still trying to improve my clutch and throttle timing on the launches as you can see that consistency has left the building. My reaction times are now all over the place as I concentrate on a clean launch technique. So until I can improve my driving with more practice winning any bracket races will be just about impossible. You know what? It's worth it!

So, where do we go from here?
The parts needed to install a set of Twisted Wedge heads have all finally arrived. The only task left is to mock up a head on a 5.0 block with a compressed head gasket and check for pushrod length. Once the pushrod length is determined and the rods are received the heads can be installed. Decision time.

So do we slap on the heads and see what a otherwise stock 5.0L will do? Or do we keep pushing the stock head/cam/intake performance envelope? There is some ET still hiding in the fan and exhaust. Tell us what you think! F/M

 

More Project GMII articles

 
pixblue
pixblue
Tech Archives Project Cars Readers Cars Feature Cars