Advice / Help?????

General Nitrous Discussion

Moderator: John_Heard

Post Reply
Message
Author
User avatar
YD-LUZ
Posts: 46
Joined: Wed Aug 03, 2005 10:17 pm
Contact:

Advice / Help?????

#1 Post by YD-LUZ » Thu Oct 06, 2005 8:50 pm

I have a 3,500 lb (w/drv) '71 Camaro street car, ran 9.61 @ 137.6 back in May, 65 degree day and no humidity. Pulled a strong 1.33 60' in a 75' wheelie and the pass before 1.31 60' spinning hard because I forgot to let air out of the slicks. Ran 3.87 330' and 6.06 @ 111.5 1/8. This was on a .087 nos / .091fuel (around a 235 hp shot) big shot plate, 6 psi fuel pres, 1,000 bottle pres, 434 sbc. Launch rpm was way high, footbraking left at about 6,000 rpm when I floored it on a mtr that I shift at 6,800 rpm. I was in high gear before the 330' mark and pulling over 7,500 rpm through the traps. Conclusion - blowing through the N/A converter!!!

Last night:
Same as above with new 9.5" tight nitrous converter, set up for 350 shot tune-up and ran more spray - .098 nos / .096 fuel (around a 280 hp shot). Oh, ran a better carb too. Planned to go up to the 350 tune-up and lean it out but got stopped because no license. Would only 60' a 1.420 leaving on the bottle - no tire spin at all and very low rpm launch-will only foot brake 1,800 rpm. Ran a 6.098 @ 115.03. So, gained 3.51 mph there but lost e.t. because the bad 60'. Ran 9.525 @ 142.91 1/4. So, gain of 5.31 mph & .085 in e.t. So, made up the loss in 60' plus overcame the terrible heat / humidity to gain 5.31 mph. Trapped 7,000 rpm.

So...
The converter is putting more pwr to the wheels + some more pwr in N20.
But....the 60' time is almost a 10th slower - ouch!!!!!

QUESTION:
How about a trans brake?????????? The car will hold the pwr easy, hell I bet it will hold a 1.20 60' time. Yank Racing (the torque converter co) thinks this is the best option. AND-go to more pwr on launch with the 350 shot. How would this work, can I floor it against the brake on the bottle??? I've nvr had a brake so I'm clueless? Is this the right move??? They said if I loosen the converter up I'm gonna have problems on the big end again. Especially on the 350 shot.

For those that care, launch pics for the Car Craft feature still turned out great, did three launches before the track opened, all three 1.42's!

Thank You for any help!!!
_________________
Just a little pump gas small block

User avatar
John_Heard
Site Admin
Posts: 5734
Joined: Thu May 12, 2005 11:20 am
Location: Resume Speed, Kansas
Contact:

#2 Post by John_Heard » Fri Oct 07, 2005 10:11 am

The tbrake will help you get more stall out of it. I'd suggust a Griner brake if you can find one. Your converter sounds super tight, I wouldn't put that big shot on it at that low of RPM. 3000-3500 or so at least or you're begging for a backfire I think.

Not to pick on your converter guy at Yank, but you might want to give Marty a call at Neal Chance, I think they have a lot more experience with getting the converter to lock up good down track and still having enough RPM to launch with.

Most people do not activate the nitrous while on the transbrake, most use a normally closed relay to break the nitrous activation circuit when the tbrake is on. I know Jason/Hellbent used to run his while on the brake but I think I'd talk that over with your tranny guy before trying it.

Looking forward to seeing your pic on the cover of Car Craft! That's cool 8)

User avatar
YD-LUZ
Posts: 46
Joined: Wed Aug 03, 2005 10:17 pm
Contact:

#3 Post by YD-LUZ » Fri Oct 07, 2005 9:33 pm

Ya know I was really pissed at the lame ass launches this week. But...it takes me some time to digest stuff. I'm thinking the big problem was a fat tune up! The videos show black smoke the entire run, especially the first part of it - even though I run a bleeder line so I have no pressure creep. Thought I had it leaned out enough with the jet spread I ran - but not-the plugs show rich too. It's a shame I got the boot, I'm thinking going to a .102 nos & .098 or .096 fuel jet would have woke her up. The 1/8 mile on numbers were the best ever, just need my 330' numbers back to where they were, and bingo. So - as of my current thinking, I need some seat and tuning time before changing it and spending more money.

To be honest - I am very proud of the Car Craft feature. I did all body work and paint, my own interior, motor, chassis, wiring, etc on my car in my attached garage, so to see my work recognized is a dream come true - hope you like the story!!! AND THANKS!

User avatar
John_Heard
Site Admin
Posts: 5734
Joined: Thu May 12, 2005 11:20 am
Location: Resume Speed, Kansas
Contact:

#4 Post by John_Heard » Fri Oct 07, 2005 10:30 pm

What tune up did you have in it? Squared or? If you were blowing black smoke no doubt it was rich. If you take fuel out also take some more timing out at the same time until you get a make a pass and see what the plugs look like. Have you read the article on plug reading on this site?

Very satisfying to see your hard work recognized like that. I love the 2nd gen Camaros, used to have a 72 Z-28 when I was in high school.

User avatar
YD-LUZ
Posts: 46
Joined: Wed Aug 03, 2005 10:17 pm
Contact:

#5 Post by YD-LUZ » Fri Oct 07, 2005 10:43 pm

.098 nos & .096 fuel, 6.0 flowing fuel pressure with zero creep because I run a bleed off line & 1050 bottle pressure with a 15 lb bottle.

Does not sound like a rich tune up huh? It was, black smoke and rich plugs. Yeah, I've read the article but I'll look at it again.

Any thoughts???

User avatar
John_Heard
Site Admin
Posts: 5734
Joined: Thu May 12, 2005 11:20 am
Location: Resume Speed, Kansas
Contact:

#6 Post by John_Heard » Sat Oct 08, 2005 7:15 am

How are you measuring the flowing pressure? 6 psi flowing through a .096 jet? Thats about a 5.34 N/F Ratio, It probably would have liked more like 5 lbs which should be about 5.85 N/F Ratio. Either go up on the nitrous jet, say to your 102 @6psi (5.79 N/F Ratio) , or start pulling fuel out about 1/2 psi or so at a time till it starts cleaning up. Some jets flow more or less than they should, the only way to know for sure what the flow is to test them flowing, preferably through the plate and measure the weight of the fuel/N2O moved.

User avatar
YD-LUZ
Posts: 46
Joined: Wed Aug 03, 2005 10:17 pm
Contact:

#7 Post by YD-LUZ » Sat Oct 08, 2005 8:15 am

Beyond wrote:How are you measuring the flowing pressure? 6 psi flowing through a .096 jet? Thats about a 5.34 N/F Ratio, It probably would have liked more like 5 lbs which should be about 5.85 N/F Ratio. Either go up on the nitrous jet, say to your 102 @6psi (5.79 N/F Ratio) , or start pulling fuel out about 1/2 psi or so at a time till it starts cleaning up. Some jets flow more or less than they should, the only way to know for sure what the flow is to test them flowing, preferably through the plate and measure the weight of the fuel/N2O moved.
Yeah, it was through a .096 jet. Thanks for your help, I think I was a jet change away from a better 60' or possibly just needed the 350 shot tune up and leaned out.

Thanks Again!

Post Reply

Who is online

Users browsing this forum: No registered users and 13 guests