MARKUS_P

I see all this monster engines and hear people talking about 500 lbsft at 2000 rpm, but what is this good for especially on a street driven car?
Peak performance around 500 HP is IMHO more than enough, and why should I build a motor that is capable of monster torque curves from 2000 rpm on if Iīm unable to transfer that kind of power to the street.
Even with wider tires and special suspension setups you risk breaking parts and I wonder why people donīt try to build smooth engines that have a steady increase of torque over rpm.
The saga of the flat torque curve is too much appreciated in my opinion.
It is true that torque is more important than HP but on a hot smallblock weīre talking about 300 lbsft at 2000 rpm at least.
The car will be easier to drive and thatīs the most important aspect.
I donīt like to drive the car and fear that I might loose control if I slam the pedal at a moderate speed.
Donīt get me wrong - the more power the better - but it must be controlable, and predictable. Everything else is not fun for a guy like me who isnīt a professional racer

groovyjay

IMO lowend torque is a good thing in a street driven car. I have 520tq from 1800rpm--> and it's very streetable. I've had a high peak hp small block and I just hated the way it behaved. I think the flat torque curve is under rated. Once you have really driven car with hp and tq exceeding 500 and you've gotten used to it you just want more :yesnod: :steering:

When are we gonna see another project update from you? Are you finished with all the fiberclass yet? :cheers:


[Modified by groovyjay, 2:40 PM 1/15/2003]

mrvette

IMO, over ~400 ft lbs is wasted with stock rear suspension style components....
tubb it out and add sticky Mickeys...well have fun sky is limit...I guess....

for a street machine, that you can drive across country without burning it up....over 450 ft lbs I feel is about the ragged edge.....
well ok, unless you do the drive in Minnesota all the time...in January....;-)))


GENE

MARKUS_P

Hi Jay
I wasnīt on the forum for quite a while now -anybody missed me? :D :p:
To be honest I just sold the vette and bought myself a honda civic....
That was a joke, okay? :blueangel:
The vette is at the paintshop right now, both T-Tops are already done. I was able to finish all the fiberglass repairs last year so I could enjoy celebrating new year in Berlin / Germany with friends.
This week we (the painter and I ) will start blocksanding the body, which was primered a along time ago.
I think weīll spend two month on painting, after that Iīll have some fun with all the electrics.
Iīll take some pics of what we do right now to keep all of you updated.

Now back to my topic - I plan to use 8x16 TT II rims with 255/50/16 tires.
I donīt think that this wheel combo is able to transfere the power your engine produces.
I can only guess - but I think a 383 with a XE 284 cam, AFR 190-heads and other goodies will be more than enough.
You know I started this topic because desk top dyno shows the differences of the cams really good. And I started wondering how much torque at low rpm is too much........

MARKUS_P

Thatīs just what I thought......
Thanks for your opinion :cheers:

73 LS-4

Well think of it this way, us Rat guys all pretty much start over that number (stock 73LS-4 is 395ft/lbs net stock at 2800 rpm) Throw a set of headers on then you already went way over that. I run 255/50r16's on the back of mine and it's not that bad, granted I can't launch the thing at anything over 2k by dropping the clutch from a stop but it does ok fine once you get about a 20mph roll going most of the time. A lot has to do with how sticky the tires are, mine are pretty sticky. But torque in the 400-500ft/lb range is very streetable in my oppinion, makes it a pleasure to drive, after all you don't have to use all that torque all the time.

:cheers:
Pat Kunz

Flareside

You have to ask yourself what type of drivability you need. Sure, 400 ft/lb may be enough to break the tires loose, but how often are you driving at the torque peak? Why build your engine so that you can use full throttle everywhere, in every gear, without spinning?

Say your car will spin the tires at a certain mph in a certain gear. What happens if you go into the next gear at that speed? Now the tires don't spin, and the car pulls like a freight train. I want my engine to make WAY more torque than the tires can take in the lower gears, because without that torque you will be SLOW in the higher gears.

IMO, nobody but the die-hard drag racers should be building their cars solely to maximize the launch from a stop.


[Modified by Flareside, 8:37 AM 1/15/2003]

MARKUS_P

Thatīs true, Flareside. But if you have to lounch your car from a standstill, you should use 1st gear asuming your gear ratio is well calculated.
Further more I was not talking about peak torque, I was talking about lounch rpm in combo with a race converter.

This is what I think is more than enough for me.
AFR190, XE284H cam, 1.6 rockers, 10.3 CR
Maybe this will be my next engine...

Flareside

Markus, I guess what I'm trying to say is this: Why would you build a street engine based on launch characteristics, automatic or not? For drag racing, I can see it, but power at speed seems so much more important to me. My solid roller 406 makes power very similar to the graph you have below, and that engine isn't scary fast at all. Sure, I can't floor it from a stop, but why would I? Bring up a graph of a forced induction engine, or even a ZZ502, and you'll see the torque that we all need :eek: :cheers:

MARKUS_P

Well Flareside, I have no experience with that kind of power.
I just donīt like to own a car that needs full concentration to get a good lounch done.
Torque at driving speed is more important - I agree.
My point is that an engine with little less torque at lounching speed makes the car easier to control -> therefore easier to achieve faster times.
I just reflect everything to the drivers skill.
And somebody like me who drives the vette a few times a month canīt have that much experience as the car would probably demand with such great power ratings. Understand what I mean? I have to save myself - you can see it as a little life - insurance :lol:

GrandSportC3

I have 410 ft/lbs of torque ON THE REAR WHEELS (probably 500 ft/lbs of torque at the flywheel)... and it's sooooo much fun... I can break my 255's loose in any gear (exept the overdrive)....

:cheers:

Olivier

bence13_33

Markus:
I think it's all personal preference. My motor is putting out around 500HP/500TQ and it's not enough. Power is addicting. While the setup you have listed for an engine build-up is nice, it would probably only run around mid-high 13's in the 1/4 which is a little slow for MY taste. It's an awesome feeling down shifting from 4th to 3rd with 500 ft lbs of torque slamming you back in the seat. I built my car to be like a 1/4 mile car, but I would like it to be known that my car is 90% street driven and 10% track car. When the whether is nice...I drive it every chance I get.

I guess it's all in what you are going for...god knows if you were going for gas mileage you wouldn't want a setup like mine (6-8mpg) :D

MARKUS_P

Mid to high 13's with that power/torque curve ?
You should be able to drop into 12`s easily IMHO.
Am I wrong?

groovyjay

Sure we missed you Markus, I'm not even going to comment that civic joke :skep: . My car is actually getting painted as we speak, I know how big :D fan of black you are so it will be your favourite colour after it comes backk from the paint shop! Keep us posted! :cheers:

gkull

Markus, Your never going to have to much torque with a 355 ci. Once your moving your going to want another 100-200 more lbs. If your have 5 or 6 speed transmisions you can build a motor with a high rpm peak tq and hp and go fast.

I like a motor that you don't have to shift down and run it to red line in every gear to get it going. My 750 cc SuperBike didn't really get with the program till 8000 rpm. But from there to 13,000 rpm it was hell on wheels. You always had to be shifting and 600cc are even worse. Tq monsters are the only way to go.

Just because you have over 500 lbs of tq it doesn't become unstreetable:) You just have to adjust your driving style. My next motor will be something like what Monty built N/A with over 600 lbs and nearly 700 hp :thumbs:

The Money Pit

Dirty Harry says "A mans got to know his limitations." I've built a dozen 350's and always found that I felt like there wasn't quite the punch I wanted. With the 406,I have to ease into it,or I'll smoke em off the line. The beauty is once you're under way,and you still have the futzpa to break them loose if you want. There's a surge of power I can only describe as what you would feel on take off in a jet plane.Knowing how to control this comes with experience,and it doesn't take long to get the hang of it.
If you're the kind of guy that floors it at every stop light,keep driving your Toyota! :leaving:

Vetterodder

If it's an option, more torque is better than less, especially for street driving. I can agree that once you have more torque than the tires can handle will make a standing start launch more complicated and that trading more high rpm torque for more low rpm torque is likely to result in lower et's. The reason that dedicated drag cars (that have tires and suspensions to handle it) launch at 5,000+ rpm is because that's where they make the most torque.

On the street though, more low end torque is a blessing. Goose it in any gear and you have immediate response, as opposed to having to wait for revs to build. If you have too much low end torque, you need driving lessons or a Civic :).

soundguy

Controlling a high-torque motor is simple - just put a heavier spring on the accelerator. :) I'm not kidding...if you use a progressive spring setup so that anything over 1/2 throttle requires both feet and a mule, you won't be giving it WOT 'accidentally'.

American Boy

The torque of an engine transfert to the wheel by the transmission and rear gear. So whatever torque you have at 2000 rpm, if you choose the right gearing you'll have the kind of response you want. For my part, near 400 lbs of torque at the engine at 2000 rpm with my 3,07 rear gear and 3,30 first gear ratio is what I'm after. I had a similar setup in a 1978 camaro with 3,50 first gear (heavier car) and it was a blast. I could burn rubber at command and still make descent 60 foot (2,10 with a 3800 lbs car, street tire). The other thing about that set up was the top speed, in 5th I ran 150 Mph and it was still going.

Stephan :steering:

Rolling Thunder

Uh-oh, you mean I goofed up going with the ZZ502, 700R4 with 2200 stall, 3.08's and 325/50/15's? Maybe I can get a refund. :lolg: :lolg:

Welcome back, Markus. :seeya

Dave