CarbedC4

Alright, im always posting random stuff but i got to thinking today. I see ALOT of you guys running about 120-122 mph on the motor without to radical motors.
Heres my setup: I make right over 500 horsepower in my race setup. My car weighs right at 3000 lbs no driver. Then i drop the entire exhaust (open header, minus 80lbs), Take out the 20lb nitrous bottle (52 lbs), and passenger corbeau seat (17 lbs). And my race weight is usually right at 3050-3070 with me in it (210 lbs).

500 horsepower @ 3070 outta run like 10.60-10.70's shouldnt it??? I dont run much on the motor but im running times around that on the bottle (maybe a little quicker but not much) What am i doing wrong here??
Ive now upped my nitrous jetting to a 250 shot. Im over 700 at the flywheel when im at the track with a 3120 race weight when nitrous is on the car. Do any of you have any programs that simulate dragstrips? because every calculator ive put my car into says i should run like 9.40 @ 144 , thats crazy fast, and im nowhere near that. I dont take the g-tech's 137 as being literal. I think im running about 134-135 or so. And id say about 114-116 on the motor (havent made many motor passes so dont know)


Can someone tell me where im not running where i should be? I see beach bum going 11.50's @ 117 on a way more mild setup than me with more weight. (and im talking about the same dragstrip he runs at too, famosa)

Im gonna quit blowing money trying to make the car faster and figure out whats wrong with my present setup. I typed a ton, so i apoligize but im hoping some of you can enlighten me


Wheelsup: runs 11.0's @ 120 on a 350 that makes about 475 hp


[Modified by CarbedC4, 7:28 PM 11/12/2001]

Vic'89

Just curious, are you making a confirmed 500 HP ?

Did you dyno ?

Vic

11sec84

Cam and heads are what makes the power. Tires and suspension put it to the ground. If you are making 500 hp then the week link is in the chassis and tires. Flo the heads. What size cam are you running again?

CarbedC4

Yea i actually dynoed and made over 500 horsepower @ 6200.
But I swear when i take the car out it doesnt feel like the power is there.
Im running a Comp Cams hyd roller Extreme Energy 294. its 242/248 .540/.562 @ 110. I personally think its healthy enough for my box stock afr 190's.

What puzzles me is there isnt much to do on the suspensions of these cars, they hook damn well stock. I run 28x12.50x15 ET Streets with a 3500 converter and a 3.73 gear. Its always been with a 700r4 before. now just switching to a th350. It just seems the car doesnt pull like it should. I believe most of it is in my out of the box never touched holley 750 doublepumper. its only had floats set and thats it. I dont know a ton about carb tuning so maybe thats a problem....it just seems my car is extremely light and should run great times but just never seems to do it.


[Modified by CarbedC4, 9:08 PM 11/12/2001]

korvetkeith

Beware of the cowl hooded, slicky tired, '84s from SoCal :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek: :eek:

Beach Bum

Carbed,

I ran your #'s on my dragstrip simulator program.... I had to assume some things such as a converter flash to 3700 rpm, shifts at 6400 with your hyd roller set-up, I also assumed your whole torque curve based upon your specs, which I feel is pretty darn close...... if you have 500 HP on the motor and a raceweight of 3070 lbs....

1.62 60 ft, 11.024 @ 125.59 mph

However, you're not running this... I knocked down power to about 400 hp and came up with this....

1.72 60 ft, 11.825 @ 116.89

I then added a 250 hp shot on top of this with 10% nos loss assumed.

1.54 60 ft, 10.38 @ 133.44 mph.

I then moved your hp back up to 500 hp on the motor and then added the 250 shot on top of that and came out to.

1.542 60 ft, 9.90 @ 140.16 mph.

What does all of this tell me.... you're definitely not making 500 hp on the motor, probably close to 400 hp, especially at that raceweight, however I agree with you, your motor combination should make at least 75 more hp in my opinion thus putting you in the low 11's on motor only. You should have a very close look at your motor set-up.... springs okay, etc....

I realize you have a Vig 3600 rpm converter, but without a doubt your torque curve would love a lot more converter.... however, streetability gets pretty tough as you go beyond where you're already at. Wheelsup has a great running set-up that is pretty much completely optimized.... he runs a lower raceweight too, has a 4000+ converter, a lot of gear and tire and he puts it to the ground.

My set-up makes very little hp, probably around 440 at the flywheel give or take 10, which is right in line for 116 mph traps at a 3500 lb raceweight... my et's are pretty good for the mph simply because I put every little last gonad of torque to the ground.... or at least try to. There's no secret... use the right gear, converter and have lots of tire. Your Carb motor wants more converter.... it undoubtly has a flat broad torque curve.

btw, I race Carlsbad... only raced Famoso once... to far of a drive for me at 6+ hours roundtrip.

cheers,
Beach

CarbedC4

oh god that just puts it bluntly. My car is doing horrible right now on the motor and i dont know why. I ran compression test and got 155 every cylinder...fine there. The problem has to be the carb,timing or something. the car feels like it runs fine but i dynoed 420 hp back when i was running a basically stock cam, 650 carb, performer rpm etc.....somethings gotta be wrong. I just dont know what to look for in a car that seems to run fine


[Modified by CarbedC4, 9:56 PM 11/12/2001]

11sec84

What's the jetting in on your carb (front/rear)? Are you still running a power valve? If so what size? Personally I'd go with a little bigger cam. However I think you can still pull some power out of the one you have. The lobe cntr is a little wide. I'd go with one more like a 106. Is your cam installed straight up or did you degree it in with a wheel? What headers are you using? Also, 383's love exhaust. What size tailpipes do you have? All these little things affect the tune of the car. When these are optimized you'll be wondering why it runs so good for what it is instead of the other way around.

MJ

Carbed, you posted about dyno numbers before, and there was some confusion about the numbers. Post the dyno sheet so we can see where you are at. My car shows 360 at the wheels NA, convertor unlocked. Race weight is 3640#s. runs high 11s @ 114-116. I know how you feel. I wanna be in the low 11s, just can't find it.

CarbedC4

11sec84: why on earth are you selling the car??? wanna get ridda some parts on that thing before you sell it??? Ive always found parting/trading out alot of things on a car before selling it will get you more overall because selling alot of certain things dont hurt the value. if you are getting rid of anything then let me know, ill drive over to swap you out some parts. of course ill throw in some money for everything i can get to trade. if you dont want to or only wanna get ridda certain things i completely understand. this time ill drive all the way so i can check out your car. Maybe ill just trailor mine up there as well.

List of stuff i want:
1) your complete exhaust after the longtubes, i have a complete custom made 2 1/2 inch exhaust out the back of the car that id trade and throw in some bucks. mines got 2 1/2 with h-pipe and dynomax race magnum (ultraflow) mufflers
2) your dominator carb for my brand new from summit 750 double pumper?? is yours a 750/850 dominator?

3) your torque converter for my new ger 3500 converter?
4) Well i ended up deciding going with the dragradialed ZR1's was a bad idea...i cant handle having my car not hook like it used to. I really LOVE the way it looks but its just not the same. Ive got a chrome set of ZR1's identical to the ones you gave me with an extra pair of used bfg dragradials additional to the 4 tires that are on the wheels. if you are interested in trading back...hehe..

sheesh where do i stop

The Dude

Sounds to me like you're not making 500+ h.p. for some reason.

I can give you an example. the engine I blew up back in April was making 420 at the flywheel and it ran a best-ever of 12.31 at 110 and change at about 300' elevation. (That's a 3,600-pound car with a TH350 and 3.08 gears.)

I haven't run in a while so I'd listen to Beach--looks like he's becoming a telemetry guy.
:D

gkull

11sec84 The price looks right! My 16 year old daughter has been bugging me about a car. So I told that I would buy her and older Vette. Because they are so cheap and she is bound to smash it up anyway. So a car like yours would be perfect. How does it drive around town?

GusBustamanteJr

The 350 tranny is probably where you lose time on the other vettes, though they are stronger, they are not as fast.

CarbedC4

uhhhhh turbo 350s are not slower than 700r4's where did you get lost in that idea? the 700r4 has a really bad spacing and its only advantage is to help an under converter'ed car get out of the hole with a deep 1st gear.

gkull

My car slowed down when i first put in a 700R4. From a TH350. It's not just the bad gear spacing. It take more HP to run a 700 or TH400 than smaller trannies.

I never had a probuilt HD high hp th350. But I got rid of the 350 when it started to make bad noises and the pan had not only black dust from the clutches or aluminum flake in the oil, but I had chunks of steel in the pan.

It seems like everybody racing goes with 400's. I have never even heard hp claims for th350's

rainman69

So, I guess if I posted this (from what I know of your car in the sig):



Peaks: 530 HP @ 6000, 513 TQ @ 5500 (fly net)

And thrown into a '95 Corvette chassis with a 700R4...Drag2000 comes up with 10.834 @ 126. (Without N2O)

CarbedC4

Geezzzzzzzzz im apparently having much bigger problems than i think. I REALLY appreciate all your guys help in ideas and running different setups and what they should run.

Well time to figure out where the poblem is. Im going to swap on a buddys new Holley 830 HP series carb and see what kinda changes i get. Also im gonna check my timing, i always just set it at idle to 11 degrees (msd pro billet distrib with vac adv plugged) and ive never checked total advance. Also ive never changed the springs, any ideas there?

Sir Sel

CarbedC4

I share your curiousity. I'm not a regular drag racer, but hope to be good soon.I have a 422 stroker C5, M6 with no suspension mods as of yet and have run only 12.15@124 on stock tires with 2 sec 60' times. I do expect much better times when the ET Streets arrive.

The G-Tech is probably right on at 137mph for you car in the quarter. It measures the speed at the very end of the quarter exactly. When drag racing the trap speed is the average of the last 66 feet.

BeachBum
Where can I find that drag racing program?

Thanks
Selvin

Bruce

don't mean to be rude. Yes carbedc4 car much faster than mine any way. Yet you keep telling us your motor produced 500-700hp with n2o. Yet this have been asked many times that you should post your dyno rwhp # so that we all can take a peek and you always seems to ignore that question. Maybe your motor not making the hp as to say it or maybe your car should much faster. Oh well.


Bruce
93Lt1 conv w/Zf6
top end mods
150hp NX jetted

427Hotrod

The ultimate dyno, and the only one that really matters is the MPH number at the end of the qtr.

It's been said that you don't race dyno's or flowbenches. Big numbers don't always equate to fast times.

All that being said your car seems to hook very well so I can't assume you are losing much there. MPH ususally doesn't move around alot even on a poor pass unless you're doing something like smoking tires past the halfway mark!

For whatever reason, you just aren't making anywhere near 500 hp at the crank. There could be many reasons it's not doing in the car what it did on the dyno. You've already named several, and I believe you need to continue with the basics. The bottom end seems sound, so I would actually measure valvespring pressure, measure cam lift at each valve to make sure a lobe isn't going away etc. There's a good chance the problem is there.

You HAVE to set total timing. Your carbed motor is going to have to be up in the 36+ range on total to get in the game. Make sure it's there for real. Are you running any kind of electronics controls on the ignition or is it a totally mechanical advance?

Go to fuel pressure next. Make sure it is maintaining while under power. Fuel pressure and valvesprings are the two things that are hardest to diagnose from SOTP feeling. They don't always just die out, they just get slower and slower.

Just for reference, my '67 had a race weight of 3520 with the old 427 in it. It made 423 RWHP through the pipes and ran 11.20's at 122-123 all day anywhere. Launching was it's biggest issue. Trying to save parts! There was probably a 10 in there, I just never got it before I installed the 540.

Start at the basics and you will find the "lost" hp.

Jim