Become a Fan!
Login
Username:

Password:

Remember Me

Lost Password?

Register now!
Main Menu
Who's Online
36 user(s) are online (12 user(s) are browsing Forums)

more...
Guru Dictionary
Print in friendly format Send this term to a friend  Liter
Metric unit of measure. In the case of engine displacement, it measures the total volume of all combustion chambers. Therefore in a 5.7L V8, each cha...
Supporting Vendors
Platinum
Mid America Motorworks
Mid America Motorworks FREE CATALOG


Gold
FIC 770-888-1662


Registered Vendors
Guru Friends
Supporting Banners

TIRERACK.com - Revolutionizing Tire Buying


Shop for Winter Tires Now!




Support This Site
 Register To Post

rklessdriver 2018 MPC Real Street - First Race of the Season
Senior Guru
Woodbridge, VA
1311 Posts
Member since:
2008/1/4 0:00



Offline
Well I am going to miss the first race of the season.

I went Friday to renew my NHRA Competition License.

Ran the car N/A on motor as I just need to make 3 passes and 2 of them only had to go faster than 135 MPH.....

Well after pass 3 as I came back around to the pit I noticed the vacuum gauge was pegged on 0 and quite a bit of smoke coming from the vent tank for the vacuum pump.

Turns out we damaged the engine very bad in GA testing back in March and it had a few pistons that were just barley hanging on by a fingernail.... running the car hard for a few 11/4 mile passes finished them off.

When things go bad on nitrous they really go badly. I got the car unloaded Sat and leaked the engine down.

Cyls 1,2,3,4,6 are ZERO leakage.

Cyl 5 is 65% leakage.
Cyl 7 is 40% leakage.
Cyl 8 is 25% leakage.

So bad, bad, bad.

Inspection camera video looks real bad in the 3 affected cyls, as there is lots of vertical scoring on the cyl walls and plenty of aluminum transfer showing at TDC.

My brother-in-Law is going to help me pull the engine out tomorrow and I will have to take it down to the family's shop in Ga next week. We will pull it apart and see if it can be saved at the current bore size or if it's going to need more work than just a hone and slamming some new pistons/rings in it.

I was hoping to have some cool video and great results to report back to the forum.

FYI ET on motor running on the better part of 6 cyls.....

10.20@137MPH - 1/4 mile. 6.60@108MPH - 1/8th mile. 1.50 60ft.

Obviously 60ft and 1/8 mile ET are terrible because of the transmission gearing (2 speed PG 1.69 to 1 low gear 1.0 to 1 high gear) and TQ converter which are set up for nitrous.... the new 4.29 rear gear did put me at about 7800RPM going thru the 1/4 traps.

Will
Posted on: 6/7 17:51
_________________
1984 Corvette. 434 SBC with a Powerglide.
Best pass - 8.48@160MPH 1.23 60ft on MT 275/60R15 Radials.

1972 Corvette. LS5 454 BBC with M20 4 speed.
Best Pass - Doing good to just pass a gas station.
Transfer the post to other applications Transfer

rklessdriver Re: 2018 MPC Real Street - First Race of the Season
Senior Guru
Woodbridge, VA
1311 Posts
Member since:
2008/1/4 0:00



Offline
I got the engine fixed and installed it back in the 84 last week. Got it running Friday with no drama.

Kinda impromptu, I took it to Test and Tune at Capital Dragway Sunday. I have not been there since 2011 when I took the 92 over there for a Corvette Club day..... It's a nice place, I really don't know why I do not race there more often.

My brother in law has a new to him 1979 Malibu with a 400 SBC that he wanted to test out.... so I figured why not go and help him maybe make a few hits with my car and make sure the carb jetting is still good.

They were supposed to have some No Time car practice and a bracket race. I figured with the N/T cars and a real race going on, the track prep would be really good.... Turned out it totally sucked.... about as much traction as a soapy car wash stall. It was deathly hot in the mid 90's*F too.... Track temp was 140*F.

I watched the N/T cars attempt to make hits and all just spun the tires. I decided to make a motor pass and we would wait and see if the track came around.

I have the rev limited set down to 7500RPM to take it easy on the new engine. The pass was easy with no drama.

1.49 --- 60ft
4.28 --- 330ft
6.57 --- 1/8th mile
109.15 MPH
8.55 --- 1000ft
10.20 --- 1/4 mile
139.43 MPH

What was apparent midway thru the pass was that I may have set the rev limiter down to 7500 but the air shifter was still set to 7800RPM. Car was on the limiter in high gear for about 3-400 feet as well.

We waited and watched but the track didn't get any better.... N/T cars were all blowing the tires off. By 6:00 PM it had dropped to about 80*F I decided to make one more pass with the 84.

1.48 --- 60ft
4.26 --- 330ft
6.53 --- 1/8th mile
109.95 MPH
8.49 --- 1000ft
10.13 --- 1/4 mile
140.15 MPH

So much time passed from my first pass, watching and helping my brother in law with his car, as well as a guy with a dragster next to us that broke a bolt off in the end of the crankshaft.... I totally forgot to reset the shifter RPM. Again the car was on the limiter in high gear for quite some time.

All in all it's pretty good... I don't expect the car to be very fast off the bottle... the rest of the car (gear and converter) just isn't set up to take advantage of the engines N/A power band. The ET didn't change much from me running my licensing passes on 6cyls either but the MPH did jump from 135 to 140 and the weather was much cooler first time out, so that is showing quite an improvement.

On both passes AFR was indicated at 12.6ish in high gear so carb jetting is good to go.... bit rich for max N/A power but it was really hot and it's a good start to be tuning the nitrous kit from.

Saturday the 11th is my first official race. Excited to get on some fly paper track prep, turn the nitrous on and see the car really get down doing what it's built to do.
Will
Posted on: 8/6 20:14
_________________
1984 Corvette. 434 SBC with a Powerglide.
Best pass - 8.48@160MPH 1.23 60ft on MT 275/60R15 Radials.

1972 Corvette. LS5 454 BBC with M20 4 speed.
Best Pass - Doing good to just pass a gas station.
Transfer the post to other applications Transfer

rklessdriver Re: 2018 MPC Real Street - First Race of the Season
Senior Guru
Woodbridge, VA
1311 Posts
Member since:
2008/1/4 0:00



Offline
Serious struggles in qualifying with of all things the fricken Nitrous WOT switch not touching the carb linkage.

Wasted both qualifying passes screwing with adjusting it before going to the old standby.... a piece of rubber hose slid over the switch arm.

Q1 ran a 6.21@121MPH. The car left on motor until it hit a bump in the surface which jiggled the switch enough for the nitrous to come on about 80ft out. That nearly wrecking the car but I held on to it.

Q2 ran a 6.30@122MPH. The nitrous came on at the hit like it's supposed to, but I had the front suspension limiters too tight and the car spun the tires at the hit.... which popped it into high gear about 30ft out and after I pedaled it to hook it up the car rattle the tires so bad down track the switch kept turning the nitrous on/off/on/off/on all the way down the track.

So with a 6.21 I ended up qualified 8th out of 15 cars.... Hard to believe other 7 drivers were having a worse day than me trying to qualify but it's true. Like I said, we resorted to sliding a piece of rubber hose over the switch arm for E1.

For eliminations, I didn't mess with anything on the tune up. I just wanted the car to make a complete pass so I could get some data.... I did loosen the front suspension limiters one link but left eh front shock rebound full tight.

As far as the tune up. Very easy. I call it "Grandma" because it's so slow even Grandma could make a pass in the car.

Nitrous progressive controller was 10%-15% in .25 second and 15% to 100% all in by 1 second.

Timing ramp was 40*, then dumping -11* at the hit and another -15* .60 sec into the run for a total of 14* going down track.

When I let go of the brake in E1 I knew it was going to be a good pass. The car felt much faster than I thought it would... and I was side by side with my opponent who has an unbelievably fast car (former N/Aa record holder).... he cut a .032 light to my .060 and he had a fender on me the entire pass until high gear, where I crept to within a bumper but with his better light, I just didn't have enough top end charge to get the win.

RT ---- .060
60ft --- 1.230
330ft --- 3.456
1/8th --- 5.327
MPH ----- 132.57

So it sucked to loose in the first round but I was super happy with the ET and MPH the car posted on it's very first full on NO2 pass. I got some great data and there is so much ET to be had by just getting some power in the car earlier in the run. There is also more power to be had by leaning out the nitrous AFR a little as it was pig rich at 11.3 AFR on that pass....

Next race is Friday in 2 weeks August 24. I am excited to get back out there and whittle the ET down to match the MPH.... With some work I hope to get that 5.1X pass before the end of the season.

Next race, I plan to knock some fuel pressure out of the nitrous kit's fuel side and add a little power earlier in the run with the progressive controller... maybe something like 10% to 30% in .25 sec and all in by .75 sec. Gonna work my way up to that a little at a time thou.... don't need anymore smashed oil pans.

Here's video from E1.

https://youtu.be/4qBv-2yI4KI

Will
Posted on: 8/13 19:05
_________________
1984 Corvette. 434 SBC with a Powerglide.
Best pass - 8.48@160MPH 1.23 60ft on MT 275/60R15 Radials.

1972 Corvette. LS5 454 BBC with M20 4 speed.
Best Pass - Doing good to just pass a gas station.
Transfer the post to other applications Transfer

TommyT-Bone Re: 2018 MPC Real Street - First Race of the Season
Chair-man of the bored
Homestead USA
30693 Posts
Member since:
2007/12/10 0:00



Offline

Interesting read .....
Posted on: 8/14 4:17
Transfer the post to other applications Transfer

You can view topic.
You cannot start a new topic.
You cannot reply to posts.
You cannot edit your posts.
You cannot delete your posts.
You cannot add new polls.
You cannot vote in polls.
You cannot attach files to posts.
You cannot post without approval.

[Advanced Search]


CorvetteForum.guru is independently owned and operated. This site is not associated with or financially supported by General Motors.

Copyright 2008-2015 CorvetteForum.guru

CorvetteForum.guru is a Guru Garage Site (Coming Soon!)

If you have any questions about our site, please contact us at Andy@corvetteforum.guru.

Powered by XOOPS 2.56 Copyright 2001-2014 www.xoops.org

Hosted by GoDaddy.com.