Not only have you seen it up close, but you suck, so yes its small. Bring your 335 horse to the AK well see whose smaller.

 

Just as a side note. If you install a ZZ4 with the cast iron manifolds, you'll probably see a huge HP decrease. I did this initially and when I installed long tube headers the change in performance was significant.

Here is a MODIFIED ZZ4 w/ LT4 (GM's "hot cam") and home ported heads with Manley raceflow valves. There are more powerful engines, but this one has served me well for the last 15 years. These numbers are off a chassis dyno. I'm estimating that I'm close to 400HP now. Wish I had dyno results from when it was a plain ZZ4 but I'm guessing the 350HP claim is pretty accurate.

Lou, if you miss the lumpty, lump upgrade yours to the LT4 cam. It's got a nice idle .... not so smooth .

 

Hmm....what's the zz4 rated at again? 355hp? And the dyno numbers above was with plenty of additional mods.... my guess is the zz4 will have maybe25-35rwhp over a stock l82 in a direct swap without other mods.

On a side note, looks like I'll be seeing very similar numbers with my $1200 Craigslist piece mail build.

 

The L-82 horsepower ratings ranged from a high of 250 in 1973-1974 to a low of 205 in 1975. In 1980, it's last year of production, the L-82 was rated at 230 horsepower.

So your off a little in your assumption and being a huge fan of craigs list I wish you luck with your build , and hope it is as good as a zz4 ...

 

I don't think I'm off at all
..... I mistakenly thought the OP was talking about a 74, A 75 l82 is more compatible to the 74 base l48.... and if you were to rate a 74 l82 the same way as the zz4 is rated it comes out to about 333hp...... 250hp is supposed to be at the rear wheels in 74 as I understand it and after you add the 25% or so drive train loss you would have about 333hp..... Which means a zz4 would have about 260-270 HP at the rear wheels and 355hp at the crank.... which isn't much of an upgrade until you get into the 75 and up years when emissions made the HP pathetic compared to its predecessors.

Maybe I'm understanding things wrong if so someone please enlighten me?

 

I don't think 250 was rwhp... I could be wrong, but I believe it's net hp.

 

My 74 l82 with headers all other things stock dyno At 220 rwhp 4 sp no ac only mod is headers

220 rwhp

 

Net HP was how you got the ratings. It was not a rear wheel rating. Also if you just look at the specs , it then becomes very hard to say a ZZ4 is not a more powerful engine. From heads , to compression , to cam it is made to make more hp then a L82 . And not just 20 more hp.

 

hi everyone... i'm in the market for a c3 and gonna go hot with it... my question is why are people not taking a 400 block and either long stroking it..or just punching to 406...like most f body guys do? seems the easiest way to get where you want power size...

thanks in advance for any input..

 

The cost of a new aftermarket block vs. finding a GOOD 400 used block is more cost effective in the long run. You can also buy an economical stroker engine for the same price or lower than piecing one together.

 

I do not buy the 20 percent drive loss theory because at what level horsepower is it from . 20 percent of a stock 190 HP l48 is a loss of 38 HP a 20 percent loss of a 500 HP 383 is 100 HP loss. There wouldn't be any higher of a drive train loss from a engine change. A drive live power loss is a constant value regardless of the HP of the motor.

 

This has been debated previously on this forum, but the percentage loss is correct....not a constant value. My own dyno tests indicated a 22% loss, as my engine dynoed 628 hp and in car rear wheel dyno hp is 490 hp with a TH400 auto trans. A dyno test is an acceleration test, not a constant speed evaluation. You could easily tow your car at 60 constant mph, but if you had to accelerate from 0 to 60 at wide open throttle, it would take a lot more hp from your engine.

 

Any gearbox (automotive or industrial) has a power loss (or "driveline loss"). Key word here is power, as in HP, not torque. As horsepower is increased, torque or rpm has to increase. An increase in torque will increase the normal load on the gear teeth. An increase in rpm will increase the sliding velocity on the gear teeth. Both of these results in heat generation and power loss. Therefore, the more HP an engine makes, the more HP the gearbox and differential will loose. That's why the "driveline" loss stays approximately at a constant percent (not HP) . There are other factors that will affect this power loss like gear teeth design, type of oil, the amount of oil, types of bearings, etc.

Think of it this way. You can rotate a transmission by hand since your producing very little torque at a very slow speed (i.e. almost no HP). If the transmission took say a constant 20 HP to rotate, an avg. human wouldn't be able to rotate the gears. When in fact, its quite easy to rotate a transmission.

Oh by the way a side note on the dyno plot I presented above. The transmission losses could have been a bit higher than normal because I wasn't in high gear with the transmission in a 1:1 gear ratio as is typically used for dyno runs. I was only in 4th gear which has a 1.24 ratio. This means that the input and output shafts were not locked together and the power was going thru an additional set of gears.

 

That's pretty informative. Thanks sharring.

 

If you have not ordered the zz4 yet maybe you would take a look at NYES Automotive.
I did alot of research before I purchased and for a reasonable amount of money they built me a pretty good motor.
406 with 530hp (on the engine dyno) on pump gas. 10:5:1 cr.

 

Ah yes the old hp loss debate, probably gone on 15-20 times. While the % of loss to the rear wheels is not exactly linear it is pretty close. I lose 23% in mine with a TKO 600, how do I know ? After the second or third debate I took my engine out and had the HP checked on an engine dyno.

I then put the engine without changing anything and put it on an chassis dyno and got the 23% loss. A TH400 can eat up to 35% or more with the big blocks in the early 70's.

For those who weren't privileged to all the debates, a big drum type chassis dyno measures the rate of change of speed of the drums and like I said while not completely linear a C3 with a 600hp motor in my car loses 23% and if I drop in a 1000hp engine I would expect about the same percentage loss within a few percentage points on the down side

 

Out to make friends I see, name fits perfect to "So there we were jawing away at the bar....."

 

Yeah he wouldn't respond to my post either... I guess that wanting a fast c3 equates to less endowment and doesn't equate for wanting a fast vette. In another post he's wanting to boost power on his l48..I guess things are getting smaller in his world.

 

Ya, lots of people claim a percentage but how many of them have changed their engine power by say 100+hp without changing anything else in the drivetrain? You certainly can't test 1 engine on the dyno and 1 chassis with that engine installed on the dyno and make any claims about the results showing that the losses are a percentage. Just having the results from a single engine vs installed wheel test is useless for proving anything in this debate.

I don't believe it's a percentage loss or a fixed loss but there are for sure fixed losses in a drivetrain which would make the losses mixed, some fixed and some varying. There are a number of things that have a fairly constant loss vs rpm number, such as the bearing friction and gear box windage. Also, the loss due to the sliding friction as the gear teeth work will be fairly constant over a certain power range. After all, the teeth face are not sliding steel on steel, they're sliding with an oil film between them. The film will keep the sliding effort fairly constant until it starts to be really stressed, in other words as you reach and go past the design limits of the gears.

I recall a thread where Tony Mamo had commented on this with some data but this is all I could find.

http://forums.corvetteforum.com/1575738864-post38.html

The thing with the above data - you could argue it could go either way by arguing errors introduced by the dynos on the different days. Still, the data is closer to a fixed HP loss than a percentage HP loss.


Also, you have to remember that engine hp is typically measured on a brake dyno and rwhp is typically measured on an inertia dyno. They measure in a different way which can skew the engine vs wheel HP results.


LOL, the losses vary with rpm too. There won't be 20hp of friction when the shaft is hardly rotating. Frictional losses are actually a constant torque loss so the HP loss starts out 0hp @ 0rpm and goes up as the rpm goes up.

 

Motorhead did. He did chasis, got in a heated debate, pulled his engine and did the dyno. Pretty cut and dried as far as losses through a manual gear box.