BUILD THREAD 86 GP 2+2~Blown 6.0

[81cutlass]

That looks like a great idea - but…..some extreme overkill. 1000-1500hp upgrade there imho

WHP that is.

I tried your 1 comp 5 rebound suggestion on the Vikings, WAY better. Thanks!

I also stuck the single adjustable comp eng. drag shocks on the front on the 90/10 setting and did a small amount of street driving with no ill comments. I am going to put 500 miles on this weekend on them in a mix of rural interstate, metro/rural highway and some city/town driving so I will report my thoughts 🙂

 

[81cutlass]

Did a pull last night with a little less fuel up top and everything looks good. I need to pull a bit more fuel out up top but nothing worrying. My fuel pressure is dropping like normal now so I am keeping the second fuel pump fuse in for the drive. Not sure if my regulator was stuck before or what?

Loaded the car up for the 200 mile drive to Dad's, and then another 40 miles to the track tomorrow morning.

I'm glad I switched to the rear springs to 5409's. The car is about 70% full load I would have for a full drag weekend and it's not squatting on the back too much which is better than it was with the stock springs. Lower but stiffer which is what I wanted.

 

[motorheadmike]

but stiffer which is what I wanted.

Bet you did... you dirty girl.

 

[81cutlass]

Well made it to the track today. Some wins some losses.

This is the track I used to race at in high school and college. It's 45 miles from where grew up and 15 minutes from where I went to college. It has changed owners 2 times in the last 10 years and I haven't been there since 2015. I drove another 2 hours to go to this track (since it's 1/4 vs the 1/8 track that is like an hour away) and I wanted to run 1/4.

Turns out the 1/4 timing system was broken so they only ran to 1/8. Frustrating that I drove another 2 hours to race 1/4 and could have ran 1/8 closer but oh well. I really want to get my launch dialed in, so I didn't NEED to run the full 1/4. Racing was supposed to start at 10am. Wanted to get racing done by 1pm before it got really hot. Got there at 10 and didn't race until 12:15. They didn't start racing until after 11am because they tried fixing the timers and failed. It was also a bracket day so they had all the 15 classes running and communication was poor on when test and tune was supposed to run.

The 1/8 mile trap speed on the left lane was broken too so the timing system was a mess.

Anyways
Run 1- 8.19, no mph

Set my clutch delay valve really tight (1/4 turn) and basically rolled it out of the hole. About 1.8 seconds for the clutch apply time. I got smooth RPM raise and the RPM made a slight 'dome' before it locked up. Basically the 2 step turns off and allows it to rev above 4000 and the clutch slips until I reach target MPH and then it locks up. The goal is to have the clutch clamp fully at 4k RPM which is like 32 MPH. If it clamps hard below that it either bogs or rips the tire off.

It fully clamped on this pass at 42 MPH so I needed to speed the clamp time up. It felt really slow but ran a 2.07 60ft which is better than what it runs when it bogs or spins.

I got called out for dumping rocks on the track? Not sure.

Pass 2- 8.3 88 mph.

1/2 turn on the valve. 1.1 second clutch clamp time. Still slow on the clutch clamp time for what I want. It seemed to slip the clutch worse (or just rev up higher?) than the first pass and when it shifted the tach was at 6000 but the wheel speed was only 30MPH. I should have just rode the thing out and let it hit the rev limiter because the clutch was still clamping. At 6000 rpm it should go like 48mph. Apparently the clutch was still slipping even through there was no line pressure. When I shifted into 2nd the RPM dropped to 3300rpm ,out of the power band, and slowed down.

I got called out for dumping fuel on the track up top. Didn't see anything obvious so I went back up.

Pass 3- 7.85, 91mph
3/4 turn on the needle valve. My computer decided to restart in the staging lanes and I didn't get data. I don't know what the clutch camp time or RPM was but it felt good. Maybe a little chatter but I don't know for sure. It didn't feel bad.

The best pass of the day.

Tech guy said I dumped fuel on the track on launch, I jacked the car up and looked for 15 minutes and didn't find anything. Not out of the sender o ring, not from the feed or return lines.

Pass 4- 2.0 60. It spin so bad I didn't even run it past 2nd gear.

1 turn on the clutch valve. Trying to speed the clamp time up. Ended up too fast at 0.3s Turns out I ripped the tire off.

Again, got called out for fuel dumping on the ground, finally got word it was from the filler neck. Looked and it was coming out of the cap. I need a different cap. The seal is bad and I had pulled the check valve out 5 years ago so it allowed it to vent and it's just going through the cap. I need to find a vented cap that is baffled. I have never had this issue since I usually race with 1/2-2/3 tank of fuel and it was probably 90% full today.

Pass 5- 8.3 no mph

2.02 60, 7/8 turn on the clutch valve. Bogged. Assumed 1 turn (pass 4) clamped too fast and just spun the tire and 7/8 was slow enough that it didn't hit the tire as hard on the launch but fast enough that it caused it to clamp before I had enough rolling speed and bogged.

Pass 6- 8.0 no mph

3/4 turn on the valve, 0.5s clamp time. Bogged, then spun. Track was getting hot, left lane was greasy. 1.9 60ft.

Pass 7- 7.99 89mph

Duplicate of last pass.

Pass 8- Spun hard, abandoned pass.


Took a review of the last few passes. It seemed like it was back to it's normal ways. Bog, spin, no logical pattern. Try to check if the clutch delay is working and it doesn't seem to be. The switch in the shifter that turns it on when it's in 1st gear doesn't seem to be working. Something related to to the adjustment of the switch. Well before I am able to adjust it the clutch pedal gets stuck to the floor. Pull pedal and it goes floppy. Turns out it bent/fatigued the master cylinder push rod and sheared at the root diameter of the 1/4 thread between the coupling and the solid 1/4 OD shaft that goes to the master. The master has been on there for 4 years, 12K+ miles, probably 50 1/4 mile passes, but apparently today was the day.

Dad drove separate so we took his jeep into town, grabbed some hardware from Menards and got it back together.

Found a 1/4 to 3/8 nut coupling and cut a piece of threaded rod to mate the push rod end that goes to the pedal to this new coupling, found a 1/4" ID to 3/8" OD bushing, and was able to push that bushing on the OD of the push rod and slide everything together. There is nothing holding the pedal to the master push rod backwards, so I have to release the clutch slowly, but it got me the 45 miles from the track to the parent's place.

Apparently the 3rd gen master isn't up to the task for a stage 3 heavy clutch. The minor diameter of a 1/4-20 bolt is small, and the shaft is cheese grade steel so I can't be surprised. I am going to try and limp the car home 200 miles tomorrow, or spend some time with Dad and try to figure out a more permanent solution.

Long term I need to replace the push rod with something stronger. Grade 8 5/16 bolt or something.

And to follow up Dad followed me back and my brake lights aren't working, so I gotta fix that tomorrow before I head back home the 200 miles.

There was a guy at the T&T that had a late model 2dr blazer with a 6.0, BTR stg 2 blower cam and an LSA blower at the same boost as me and he said his car runs 10.90's. Essentially as close to my setup I have you can get realistically. He runs 1.55 60ft and I struggle to get 1.85's. I am making the power for 10's. I just gotta get the launch solved.

Wins!
My fuel system (twin pumps) works good.
I didn't wheel hop
Didn't miss a shift any run
Tires didn't rub
Rods are in the block, rear end didn't blow up


Losses
Broke the clutch push rod
Didn't dial in the clutch clamp time/launch due to the engagement switch going out of adjustment


Got a few other projects to do before I head to the track again but there's a path forward.

 

[Streetbu]

Not every day can be a solid win, but you're still persevering thru it. 🏆

 

[motorheadmike]

It's good that you got a chance to visit this in some detail. You will get it solved, even if it is a longer iterative process than you desire.

I would definitely look at building a really robust clutch rod. Because it is a bit of dog's breakfast right now. Like huge and adjustable. Maybe find some thick walled CM tube and RH/LH thread it internally. I dunno. It's early.

Car looks awesome with the slicks on it.

 

[64nailhead]

Sounded like fun no matter of the result.

Now you have some data to look at as well, and NO TIRE SHAKE has to be big win?

 

[Texas82GP]

Well made it to the track today. Some wins some losses.

This is the track I used to race at in high school and college. It's 45 miles from where grew up and 15 minutes from where I went to college. It has changed owners 2 times in the last 10 years and I haven't been there since 2015. I drove another 2 hours to go to this track (since it's 1/4 vs the 1/8 track that is like an hour away) and I wanted to run 1/4.

Turns out the 1/4 timing system was broken so they only ran to 1/8. Frustrating that I drove another 2 hours to race 1/4 and could have ran 1/8 closer but oh well. I really want to get my launch dialed in, so I didn't NEED to run the full 1/4. Racing was supposed to start at 10am. Wanted to get racing done by 1pm before it got really hot. Got there at 10 and didn't race until 12:15. They didn't start racing until after 11am because they tried fixing the timers and failed. It was also a bracket day so they had all the 15 classes running and communication was poor on when test and tune was supposed to run.

The 1/8 mile trap speed on the left lane was broken too so the timing system was a mess.

Anyways
Run 1- 8.19, no mph

Set my clutch delay valve really tight (1/4 turn) and basically rolled it out of the hole. About 1.8 seconds for the clutch apply time. I got smooth RPM raise and the RPM made a slight 'dome' before it locked up. Basically the 2 step turns off and allows it to rev above 4000 and the clutch slips until I reach target MPH and then it locks up. The goal is to have the clutch clamp fully at 4k RPM which is like 32 MPH. If it clamps hard below that it either bogs or rips the tire off.

It fully clamped on this pass at 42 MPH so I needed to speed the clamp time up. It felt really slow but ran a 2.07 60ft which is better than what it runs when it bogs or spins.

I got called out for dumping rocks on the track? Not sure.
View attachment 179517

Pass 2- 8.3 88 mph.

1/2 turn on the valve. 1.1 second clutch clamp time. Still slow on the clutch clamp time for what I want. It seemed to slip the clutch worse (or just rev up higher?) than the first pass and when it shifted the tach was at 6000 but the wheel speed was only 30MPH. I should have just rode the thing out and let it hit the rev limiter because the clutch was still clamping. At 6000 rpm it should go like 48mph. Apparently the clutch was still slipping even through there was no line pressure. When I shifted into 2nd the RPM dropped to 3300rpm ,out of the power band, and slowed down.

I got called out for dumping fuel on the track up top. Didn't see anything obvious so I went back up.
View attachment 179518

Pass 3- 7.85, 91mph
3/4 turn on the needle valve. My computer decided to restart in the staging lanes and I didn't get data. I don't know what the clutch camp time or RPM was but it felt good. Maybe a little chatter but I don't know for sure. It didn't feel bad.

The best pass of the day.

Tech guy said I dumped fuel on the track on launch, I jacked the car up and looked for 15 minutes and didn't find anything. Not out of the sender o ring, not from the feed or return lines.

View attachment 179515

Pass 4- 2.0 60. It spin so bad I didn't even run it past 2nd gear.

1 turn on the clutch valve. Trying to speed the clamp time up. Ended up too fast at 0.3s Turns out I ripped the tire off.

Again, got called out for fuel dumping on the ground, finally got word it was from the filler neck. Looked and it was coming out of the cap. I need a different cap. The seal is bad and I had pulled the check valve out 5 years ago so it allowed it to vent and it's just going through the cap. I need to find a vented cap that is baffled. I have never had this issue since I usually race with 1/2-2/3 tank of fuel and it was probably 90% full today.

Pass 5- 8.3 no mph

2.02 60, 7/8 turn on the clutch valve. Bogged. Assumed 1 turn (pass 4) clamped too fast and just spun the tire and 7/8 was slow enough that it didn't hit the tire as hard on the launch but fast enough that it caused it to clamp before I had enough rolling speed and bogged.

Pass 6- 8.0 no mph

3/4 turn on the valve, 0.5s clamp time. Bogged, then spun. Track was getting hot, left lane was greasy. 1.9 60ft.

Pass 7- 7.99 89mph

Duplicate of last pass.

Pass 8- Spun hard, abandoned pass.


Took a review of the last few passes. It seemed like it was back to it's normal ways. Bog, spin, no logical pattern. Try to check if the clutch delay is working and it doesn't seem to be. The switch in the shifter that turns it on when it's in 1st gear doesn't seem to be working. Something related to to the adjustment of the switch. Well before I am able to adjust it the clutch pedal gets stuck to the floor. Pull pedal and it goes floppy. Turns out it bent/fatigued the master cylinder push rod and sheared at the root diameter of the 1/4 thread between the coupling and the solid 1/4 OD shaft that goes to the master. The master has been on there for 4 years, 12K+ miles, probably 50 1/4 mile passes, but apparently today was the day.

Dad drove separate so we took his jeep into town, grabbed some hardware from Menards and got it back together.

Found a 1/4 to 3/8 nut coupling and cut a piece of threaded rod to mate the push rod end that goes to the pedal to this new coupling, found a 1/4" ID to 3/8" OD bushing, and was able to push that bushing on the OD of the push rod and slide everything together. There is nothing holding the pedal to the master push rod backwards, so I have to release the clutch slowly, but it got me the 45 miles from the track to the parent's place.

Apparently the 3rd gen master isn't up to the task for a stage 3 heavy clutch. The minor diameter of a 1/4-20 bolt is small, and the shaft is cheese grade steel so I can't be surprised. I am going to try and limp the car home 200 miles tomorrow, or spend some time with Dad and try to figure out a more permanent solution.

Long term I need to replace the push rod with something stronger. Grade 8 5/16 bolt or something.

View attachment 179519

And to follow up Dad followed me back and my brake lights aren't working, so I gotta fix that tomorrow before I head back home the 200 miles.

There was a guy at the T&T that had a late model 2dr blazer with a 6.0, BTR stg 2 blower cam and an LSA blower at the same boost as me and he said his car runs 10.90's. Essentially as close to my setup I have you can get realistically. He runs 1.55 60ft and I struggle to get 1.85's. I am making the power for 10's. I just gotta get the launch solved.

Wins!
My fuel system (twin pumps) works good.
I didn't wheel hop
Didn't miss a shift any run
Tires didn't rub
Rods are in the block, rear end didn't blow up


Losses
Broke the clutch push rod
Didn't dial in the clutch clamp time/launch due to the engagement switch going out of adjustment


Got a few other projects to do before I head to the track again but there's a path forward.



View attachment 179520
View attachment 179521
View attachment 179522

This is what we're running on my brother's car. Not saying you should buy one, just wanted you to see it for ideas.

Adjustable Clutch Master Cylinder Kit for 1998-02 Camaro & Firebird LS1

This F-Body Adjustable Clutch Master Cylinder Kit solves many drivability issues with your manual transmission F-body (Camaro, Firebird, Trans Am). The adjustability allows for use with aftermarket performance clutches and solves issues that plague OEM clutches.

www.tickperformance.com

With your lathe and fabrication skills, you'll be able to build what you need. Hope you get the car limped home ok. Check the infamous aluminum wire in the trunk on the brake lights.

 

[81cutlass]

Limped the car home. Actually no issues, took it a bit careful on clutch released and changed my route to dodge some construction and ended up going through other construction so I ended up crawling through slow traffic for 20 minutes inching forward on the clutch which is not what I wanted. Regardless it made it back fine.

Had the windows open and realized 1/2 through the trip that I have AC, why am I not using it so I clicked it on and drove in relative comfort.

It's good that you got a chance to visit this in some detail. You will get it solved, even if it is a longer iterative process than you desire.

I would definitely look at building a really robust clutch rod. Because it is a bit of dog's breakfast right now. Like huge and adjustable. Maybe find some thick walled CM tube and RH/LH thread it internally. I dunno. It's early.

Car looks awesome with the slicks on it.

Yeah it's totally ugly now. Going to start from scratch on something new. It was relatively normal looking before I hacked it together in the pits last afternoon and ended up with what I posted.

I have always just had the stock rod end coupler on the pedal side. I'm going to put a heim so I have another degree of freedom and probably step up to a grade 8 5/16 or 3/8 push rod. Copy that tick style part.

Yeah the 15x10's fit and looked good. I did run the 1/4" spacers and no rubbing. I'm happy with them!

Yeah it's taking longer to work through it than I want but I'm making progress.

Sounded like fun no matter of the result.

Now you have some data to look at as well, and NO TIRE SHAKE has to be big win?

For sure. I have some good data and had a good but challenging time.

It sight chattered one run but I did some some tire pressure stuff and had a crap burnout. I let out right away and the rear is still in one piece.

This is what we're running on my brother's car. Not saying you should buy one, just wanted you to see it for ideas.

Adjustable Clutch Master Cylinder Kit for 1998-02 Camaro & Firebird LS1

This F-Body Adjustable Clutch Master Cylinder Kit solves many drivability issues with your manual transmission F-body (Camaro, Firebird, Trans Am). The adjustability allows for use with aftermarket performance clutches and solves issues that plague OEM clutches.

www.tickperformance.com

With your lathe and fabrication skills, you'll be able to build what you need. Hope you get the car limped home ok. Check the infamous aluminum wire in the trunk on the brake lights.

Yeah thanks for that link, gives me some ideas. I think I'm going to do something with the heim end.

Thankfully the brake lights were just a corroded connection at the steering column plug so it was an easy fix.

 

[81cutlass]

GoPros on the rear tires make identifying launch problems SO much easier.

I won't race again without it. I've had the damn camera for 10 years (it's a gopro 1) and last weekend was the first time I pulled my head out of my arse and stuck it to the quarter.

Instant confirmation if it spins, bogs, or is good when used in combination with HPT data.