cant do burnouts

[bryonbush 85]

So kinda got embarrassed today. while my car is pretty quick, i went to do a burnout while pulling out of a buddies and noting..just launch with a lot of noise. this is on a new 351w Edelbrock performer rpm heads and intake, comp cam w/270 duration , dougs try-y, holley 750 and 3.80 posi. car runs good put never dyno'd the car or really dialed in the carb. never really have that obnoxious smell of over fueling and the spark plugs appear to be in the norm. 

 

with that said i ordered a wide band system to help me dial things in. with that said... this car should be able to turn the tires pretty quick. anyone have any clue on where to start looking? my first thought is to think that im running lean while hammering down. 

[Rsmach1 71]

Or rich, could be alot of things, carb, timing ect. What is your timing, initial, total, vacuum advance, exactly what 750 carb, double pumper, or vacuum secondary.

 

Edit, automatic? Torque converter?

[1969_Mach1 333]

+1 Rsmach1.  Could be a lot of things.  In addition to what Rsmach1 mentioned the Edelbrock performer is not the best choice for a street performance intake. A 750 cfm carb is a little on the large size for a mild 351.  Even if it is a vacuum secondary it may bog on acceleration until enough air speed starts pulling fuel through the main circuit on the primaries.  I would think its a little sluggish on acceleration and not as crisp as it could be.  Stock and mild 351W's seem to run good with 650 and 700 CFM carbs.  The cam is kind of mild but probably good for low and mid range power.  The tri-y headers are also good for low and mid range torque.  Actually, other than the slightly large carburetor the motor configuration sounds good for low and mid range power.

 

I think it will be a combination of tuning and maybe a couple of parts changes to "wake up" the motor.

[BandBSTANGS 15]

Is the cam degreed in properly?

[DRASTiK 22]

When you stand on the throttle, is there a momentary pause before the engine responds, or is the throttle response immediate?

[Rsmach1 71]

+1 with 1969_Mach1 and BANDBSTANGS, I agree 100% a 750 is big for a mild 351w. For your combo a 650 would work much better on the street. I think 1969_Mach1 miss read your combo as I understood you to have the RPM intake wich is fine and a great intake. As for your cam the comp cams 270 is an older but good grind, they list it as "the largest cam with a stock converter", but to get the most out of it you should have a mild stall converter as that cam starts working @ 1800-2000 rpm. Also as asked was the cam "degreed" in? Be sure to list your timing as it can make a big difference.

[Brian Conway 264]

So I gotta ask how long does it take to get to 1800-2000 rpm ?    That would seem to be the issue.  Brian

[1969_Mach1 333]

Yeah I misunderstood and thought the OP had the crappy Edelbrock Performer intake.  So maybe just some timing work and a smaller carb are in order.

[bryonbush 85]

i didn't build the motor, just bought the go fast parts. the company has a very good reputation for their work and has been in business for a long time so i think its |

safe to say the cam is timed right. yes the intake is the RPM. originally i had 2.79 rear gears so it was built for low-mid power. Im running a Holley 4160 carb. trans is an AODE with standard converter. when i jump the gas there's no hesitation and seems pretty consistent through the gears and speed. downside is i dont have a tac in this car yet so knowing an exact rpms is just a guess at this point. timing is set just below a ping; dont remember the exact numbers off the top of my head. 

 

one thing ive always wondered if this would hut my situation: i have very little hood clearance for a filter. i had to go with a 2" filter just to close the hood. maybe im thinking too much into this but im wondering if going with a breathable filter top would help my case. it will be interesting to see what the wideband reads when i get it in this weekend and give me a better idea on where to go from here. 

[1969_Mach1 333]

K&N has info for sizing their air filters.  In their example you'd be surprised at the size they recommend.  Here is a link,  http://www.knfilters.com/filter_facts.htm  scroll down towards the bottom to find their formula to determine the air filter size.  Along with filter size there needs to be sufficient room between the lid and top of the carb.  Holley recommends a minimum of 1" clearance.  I have milled off the choke horn on my carb to get good clearance between the lid and top of carb.  Some people install a filter lid when they have this situation.  But then I think most of the air is going to enter through a 5-1/8" diameter circle above the carb. 

[Brian Conway 264]

Good rpm's and a 3:79 rear end spinning the tires shouldn't be a problem.  Jack it up and see if you can hand spin those wheels. Try running it thru a couple gears and check your getting both wheels spinning.  Brian

[Raven R code 281]

All you might just need is a nice 428 cobra jet sitting under the hood. I would also keep an extra set of tires handy (they go quick). ;)

[Midlife 814]

Good rpm's and a 3:79 rear end spinning the tires shouldn't be a problem.  Jack it up and see if you can hand spin those wheels. Try running it thru a couple gears and check your getting both wheels spinning.  Brian

He said he had a 2.79:1 rear end.  That, to me, says a lot about not doing a burnout.

[bryonbush 85]

Gears were 2.78, now 3.80's

[Brian Conway 264]

Well Byron did mention he had a 2:78 gear set but is now running 3:80's and yes this conversation is normally about needing more traction.  So, gotta ask, are you running a pair of massive street drag radials ?    Brian

[bryonbush 85]

Nope 17*8 with street tires.

[Brian Conway 264]

I would check the drum brake adj. to make ,sure your not dragging some locked up shoes.  I would check the Posi operation as suggested previously.  I would go find a puddle of water, drive into the middle of it, apply the brakes, bring the rpm's up to about 1000 or so, stab the gas, let off the brakes and see what happens ?  Brian

[Rsmach1 71]

originally i had 2.79 rear gears so it was built for low-mid power.

With 224 degrees duration @. 050 that cam is all about midrange, peak torque is @ about 4500 rpm, and peak HP is @ around 5500 rpm. The rpm range as listed by comp is 1800-5800, for that cam to have any grunt from a standstill you need a converter with a stall about 500 rpm above 1800, or a 2300 stall min. Doing this will allow your engine to get into it's powerband sooner, one thing to be careful of though is to not get a stall converter rated higher than your cruse rpm on the hwy. Your probably thinking Comp said it's OK with a stock converter, and it is, if you're willing to give up the off the line grunt you want, and just be happy with great midrange power only.

[1969_Mach1 333]

I have wondered what static compression ratio the engine has?  In my mind that will help get an idea of what kind of power to expect.  An 8 inch wide wheel is rather wide.  It may never do a great burnout with that wide tire unless there is more horsepower.

 

Rsmach1 might be on to something with a different convertor.  There's mot much else left.  Like he mentioned make sure the stall speed isn't higher that your cruise RPM.

[barnett468 418]

.

Your post is a little vague, please explan EXACTLY in DETAIL just what the problem is.

 

if you are at a stop and nail the throttle to the floor and the tires dont spin, you will need to power brake it which is hard on the engine mounts and a stock trans.

 

to get an "impressive" burn out, you may need to install a stall converter even though you have 3.80 gears, because your tires are likely around 27" tall and 9" wide . . a 2000 to 2400 will work with the 2400 providing the most tire smoke for the buck.

 

post your exact cam part number

 

post your exact tire size

 

Also, as was mentioned, compression is important . . if it is less than around 9.5, you would benefit from increasing it to around 10.0 - 10.25 . . if you live near sea level, and take a compression test witha GOOD gauge, and  the plugs out and the throttle open and it is less than around 150, you could benefit from more compression . . if you are at 160 or above you have enough..

 

a vacuum secondary 750 is not too big for your app although a 680 might work a little better . . if you had a mechanical secondary 750, it might cause a slight hesitation if you floor it from a stop.

 

if you do have a vac secondary, i would get a set of holley secondary springs and install the white one and test drive it . . if it bogs while accelerating, keep trying the next heavier spring until it stops bogging . . the stock spring is fairly stiff and often causes the secondaries to open later than they could.

[bryonbush 85]

im not a huge fan of power braking to do a burnout and that's half the reason why i wanted 3.80 gears when i did the swap...rolling burnouts. 

cam:Camshaft, Hydraulic Roller Tappet, Advertised Duration 270/276, Lift .513/.513, Ford, 351W, Each http://www.summitracing.com/parts/cca-35-421-8

Tires: 215/55r17

Carb: http://www.summitracing.com/parts/HLY-0-80508SA

 

Im curious with the trans/stall. with the AODE i can change the lockup at different points. not sure is this effects first gear or not. In my dad's fox and 95 mustang i would be able to do burnouts (not huge at all) with a stock trans so i would think* that with this motor it wouldnt be an issue. 

 

i dont have the compression info available right now. hopefully i can get it this weekend. 

 

i know the brakes are not dragging and they both wheels spin as i left two tracks in the dirt road. 

 

the motor doesn't seem to bog at all when i punch it and it feels pretty good off the line and through the rpms, but having never tuned in the carb, thats why i decided to get the AFR kit. 

[sportsroof69 13]

Sounds like a converter problem.....if you call not blowing the tires off a problem.

[Rsmach1 71]

Well that makes a difference, in your original post you listed your cam as a Comp 270 duration, which made me think Magnum series, very different then what you have. Not my pic.

[RPM 1,190]

This would be a great time to post a video of you attempting to smoke the tires. Based on your drive train me thinks your rear tires should be bald. Now let's see that video!

[bryonbush 85]

RPM: I'll get a video this weekend. I'm lowering the car now so it's on stands.