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Discussion Starter #1
Just curious what all feel is above average HP and TQ to the rear wheels for a street car with a BBC? I hear people talk about how much power they think they have but bet if truth be told they would be shocked if they saw what was actually getting to the rear wheels.


This is just a fun topic not looking to start a war. I had my car on a chassis dyno last year and it is going back on this Friday when we put the new carb on.
 

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Too many variables IMO. Compression ratios, intake and carb options, heads, etc. to hazard a guess... The average horsepower of a 1970 and older BBC is going to be more than '71 and newer, primarily due to a drop in compression ratios I'm guessing - don't know for sure 'tho...just my .02.
 

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Basically on an automatic with a 12 bolt you will loose about 25% to the tire (some as high as 30%). For example the 1970 LS6 Chevelle was rated at 450 hp but that was with headers when GM rated it and the chassis dyno had the old inefficient cast iron manifolds so that hurt it more than normal the LS6 did 295 hp to the tire. They also did a 426 stock Hemi car and that did like 335 HP to the tire. I think if you put a motor on a dyno and then put in car and assuming you had headers in both tests 25% loss. With a stick 20% loss. My Chevelle does 545 HP to the tire and has 725 motor HP (25% loss) with turbo 400. Another guy I know had 690 hp on motor installed motor rolled it over to next bay and it did like 520 hp at the tire. The newer cars are more efficient like 15% loss to the tires. The TQ loss seems to be a little less percentagewise so if you lost like 25% on HP the tq maybe like 23%.
 

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Discussion Starter #5
Everyone's version of "street" is different.

I have a very street-friendly 383" LS1 stroker putting down 434hp/449ft-lbs to the wheels, and I was rather disappointed in that... If I was building a BB car, I'd want at least 600 to the wheels.

600 HP to the rear wheels? seems like you would need to build quite a beast to accomplish that :) I will share my numbers after I get mine dialed in on Friday. The way it sits now I think I am at 430 HP and 480 TQ to the rear wheels. Guy that does my work said that is very respectful for a street friendly engine. I have thought about doing things to get more, but then I get realistic and think for what... I rarely even use what I have now :) and it is really well behaved, will idle for days and with the TKO600 dropping down to 15 or so cause no lugging or bucking, if I am between 4th and 5th.


I have a 454. bored 30 with Eagle rotating assembly, 10.6 to 1. Brodix Race Rites, ARH Headers. Cam is 566/566 224/224. Air Gap and putting an 850 DP on it this week. taking off the QF 780 with vacuum secondary.


Like I said was not looking to get into a big debate, just curious..
 

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Real question here. At what point is the power counterproductive? I mean, at what point do you struggle to keep traction with normal tires? I may be off base, because my car is still in pieces, but seems like 450-500 rwhp is about the consensus of the sweet spot of enough power but not so much that you lose drivability in a street car. If you go with slicks or strictly a track car of some kind, all bets are off. My goal is 450-500rwhp naturally aspirated, and if that doesn’t work I guess I will eventually turbo or super charge it.
 

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My Mark Jones 468 made 625 HP/625 TQ at the shop dyno. Rear wheel 440 HP on dyno was with restrictive headers and 2.5 Flowmaster exhaust . With TH400/Gearvendors and a loose convertor and 3.73 gears, Power steering. A/C hooked up (Vintage Air) etc. Loaded street car.
 

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1968 Chevelle Malibu, upgraded to a 396/TH400 from a 327/PG
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I’m not sure. My car likely has in the 300 horse/350 torque range at the wheels and it’s plenty for me. I’m more than happy with it.
 
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A sign of maturity Gavin! To Steve's point, I'd be happy with 500+ to the rear wheels. MJ468 600/600 , low restriction exhaust and a clutch. I'm happy with less now, but prefer a different charateristic, like +150 ft lbs from my 427.

ALSO, that 600/600 to me is almost ABOVE the limit of street car chassis.
 

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The dyno is a tool to be used to help tune the motor and see what's going on. It gives a general idea on the situation. I think the track is the place where you can do more testing to get the results but also get driving dialed in etc. Some cars are also not set up for the track as good as others like gearing and handling/launching stuff etc. so they may have the same RWHP/TQ but one does much better than the other due to traction etc. People focus on the hp but also the tq and how the curve is also very important. On the 600 hp to the tires with a BBC you will need about 800 hp if you go an automatic. This could be accomplished a variety of ways from large cubes for NA to blower/turbo nitrous. On the NA the combination will vary if you are going to use pump gas and is this a race only or street car etc. I have a 540 that does 545 / 515 (hp/tq 6,100/4,900 rpm) to the tire and it is zippy.
 

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I made just under 300Hp to the wheels uncorrected. 4 door 1957 chevy.
Buddy made well over 500 Hp to his wheels coyote 2015 mustang supercharged 5.0 Not stock.

I beat him in a heads up race at the local drag strip.
Beat other cars with 475 to the wheels.

Just a number and like said the drag strip is where it happens.

I have been in a Dodge with 750 to the wheels and it felt very slow but was a 5000 lb ride so it needed it.
Fox body Mustang i was in with 600 to the wheels and 3.23 rear gears TH400 trans.
That thing you could not control on the street.. 35 mph in high gear would blow the tires off uncontrollably.

At the 1/4 mile drag strip it went 9.1 ET.
Congrats to you that put it to the ground.
I put mine to the ground and that wins races.
So my under 300 to the wheels works well.
Yea i would like much more but not so much that i can't pull my 20 foot Pontoon to the lake 150+ miles away :)

Here is my under 300 to the wheels vs the 2015 coyote mustang of my buddies. He has smaller blower pulley exhaust and a tune. 6 speed and 373 gears. Fun stuff. He sold it a couple weeks after the race.
 

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I'll take a time slip any day over a chassis dyno number. JMHO and experience. Not here to debate it. Each is own.

I take pride in the fact I drive my car 200 miles round trip to the drag strip,look 100% STOCK and get one of these:
 

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I made just under 300Hp to the wheels uncorrected. 4 door 1957 chevy.
Buddy made well over 500 Hp to his wheels coyote 2015 mustang supercharged 5.0 Not stock.

I beat him in a heads up race at the local drag strip.
Beat other cars with 475 to the wheels.

Just a number and like said the drag strip is where it happens.

I have been in a Dodge with 750 to the wheels and it felt very slow but was a 5000 lb ride so it needed it.
Fox body Mustang i was in with 600 to the wheels and 3.23 rear gears TH400 trans.
That thing you could not control on the street.. 35 mph in high gear would blow the tires off uncontrollably.

At the 1/4 mile drag strip it went 9.1 ET.
Congrats to you that put it to the ground.
I put mine to the ground and that wins races.
So my under 300 to the wheels works well.
Yea i would like much more but not so much that i can't pull my 20 foot Pontoon to the lake 150+ miles away :)

Here is my under 300 to the wheels vs the 2015 coyote mustang of my buddies. He has smaller blower pulley exhaust and a tune. 6 speed and 373 gears. Fun stuff. He sold it a couple weeks after the race.
That was one hell of a launch! I bet he had 12-15 MPH on you at the top end. What were the times?
 

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I'll take a time slip any day over a chassis dyno number. JMHO and experience. Not here to debate it. Each is own.

I take pride in the fact I drive my car 200 miles round trip to the drag strip,look 100% STOCK and get one of these:

:thumbsup: I'll take a time slip over dyno numbers any day too. My car made something like 325 HP at the wheels. Runs 11.70's @ 116. Plenty of "600 HP" cars that are slower. Had a buddy with a supercharged 2003 Mustang, made 457 HP at the tires. He could not make a clean pass in that car, broke lots of stuff too. I think the best he did was mid 12's with that car. We used to joke that he was an 12 second driver with a 11 second car.
 

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I have a 720ish whp V that grandma can get in and drive, or I can go click off low 10.20's with ease. The dyno was used as a tuning tool only, quite necessary as we know. My '66 makes unknown hp, but I'd guess around mid 600's flywheel. The car will definitely keep your attention, and grandma ain't drivin' it. The car will likely never see a dyno, but would be interesting to see whp on it.
 

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Sorry I went off-topic above. The "600" comment is the magic number that it would take to get me to consider a BB for the next upgrade from where I'm at now rather than the current considerations, which are also off-topic. (boost or more cubes... or both) Either way, it's getting expensive to go up from here!

As for the timeslip, I'll find out at Dragway 42 at the Northern Ohio show! :thumbsup:
 

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That was one hell of a launch! I bet he had 12-15 MPH on you at the top end. What were the times?
Yep he was charging hard and had 18 MPH on me at the top end his 12.473 to my 12.864.
But I got him at the light my .235 reaction to his .685.
I turned a 1.728 60 foot and 8.0 1/8 mile to his 2.146 60 foot and his 8.3 1/8 mile et.
I only won by .0595 seconds but it is a win in a heads up drag race which is what we were doing.
First one to the end wins.




I do agree 600 wheel HP would be ridiculous in the right car.
 

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Yep he was charging hard and had 18 MPH on me at the top end his 12.473 to my 12.864.
But I got him at the light my .235 reaction to his .685.
I turned a 1.728 60 foot and 8.0 1/8 mile to his 2.146 60 foot and his 8.3 1/8 mile et.
I only won by .0595 seconds but it is a win in a heads up drag race which is what we were doing.
First one to the end wins.




I do agree 600 wheel HP would be ridiculous in the right car.
I think there are 2 lessons here: A) you were a better driver with reaction time of almost 1/2 second and you may have shifted better during pass; B) second your car was better suited for what you were doing via the 60 foot. I think that a lot of times a bad 60 foot can just continue through the whole process. So practice and make sure your car is set up for what you are trying to do or at least be in ball park. These guys show up with the powerful cars with street tires and can't launch or have to back off on the throttle then go back on etc. Plus I think the hp is only part of the equation and low set of gears (assuming you have traction) can do wonders for the et.
 

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But I got him at the light my .235 reaction to his .685.
I turned a 1.728 60 foot and 8.0 1/8 mile to his 2.146 60 foot and his 8.3 1/8 mile et.
Was this his first time at the track? I wouldn't expect him to stay that slow for long if he has any desire to practice and get better.
 
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