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Sobering L28 dyno results again!


Drax240z

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I just stumbled across this page.

 

http://zccw.org/Club/MembProfile/DerekS/details.htm

 

You can see his dyno results from a link on that page as well... Ouch. From the list of mods there I would have expected much more. (perhaps his tuning wasn't ideal) For the price he has into that engine you could definately have other alternatives, that would make more power. (If more power was your ultimate goal, that is)

 

 

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Drax240z

1972 240z - L28TURBO transplant on the way!

Drax's 72 240Z Turbo

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i heard the old canon intake manifolds suck.but thats the kind of used stuff you find laying around.robello has been known to build a 3.1l street motor with su carbs that makes 200 hp at the wheels.i wonder what a 2.8 or 3.1 with weber style fuel injection throttle bodys at about 10 or 11 to compression would make.then it would just be dyno time to tune it.i dont have the cash to build r&d engines .but my turbo runs good and it is a daily driver so right now i am not planning any projects on my z for awhile.

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Looks like their club must have had a dyno day. You missed a couple others - a purist car whose only mods were 'period correct' that made ~107rwhp (which is fine - sounds like bone stock was what he wanted), and a nice looking 5.7l V8 that made 240rwhp.

 

The first dyno day I went to was with the Ford Motorsports Enthusiast's club. These can be pretty humbling experiences. There was this guy that showed up with a C4 Corvette that was blipping his throttle everywhere he went, and talking smack about how he had twisted wedge heads, a special chip, Borla Exhaust, etc, etc, and had blown away ZR1 Vettes, and Vipers.

 

250rwhp.

 

He started talking about how there must be something wrong with the dyno, and that it must be reading low. About then, one of the Mustang guys pointed out to him that my 2.8l Datsun had just pulled 120hp more a few runs earlier redface.gif

 

I'll never forget the look on his face...

 

Anyway - my point was that L28s aren't the only ones that get dissapointing results. Oh - and there are some cool Mustang guys out there... smile.gif

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250rwhp. I'll never forget the look on his face...

 

 

Too bad you didnt get a picture of "That look on his face." Why do people have to be like that.

 

I dont even care if you're running a souped up Honda or even a Z-Purist who just laid 20K to have his car restored; its your ride-enjoy it w/out being a jerk & belittling others simply because they chose something else: I love humbling arrogant morons: Even still after their humbled-I wont rub it in their face. Let your performance be the talker-keep the trash talking to yourself!

 

I personally dont understand spending 15-20K on a restoration that wont see the short side of an 18.00 second 1/4; to me that's wacky-but more power to them & I'll pat you on the back-congratulate you on your hard work & give you a big thumbs up!!

 

I'm a gear head-if it doesnt leave rubber on the ground-dont want it (That's my choice-not a prerequisite for others to live by).

 

 

 

[This message has been edited by Kevin Shasteen (edited February 07, 2001).]

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Guest norm[T12SDSUD]

It looks like the biggest problem with this guys setup is the CR. He needs to be closer to 11:1 CR with his cam selection. 9.5:1 is simply too low to make any HP with his current setup.

 

 

Later,norm

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Guest norm[T12SDSUD]

Another thing is that he has too much carb for his selected cam duration and lift. He is topping out at 5400 rpm for his peak HP. He should be topping out closer to 6500 rpm with triple webers. There is no sense in running triples when your HP peak is near 5400 rpm.

 

He should get a bigger cam that will make better use of the triple webers potential. He should be peaking his HP numbers closer to 6500 rpm with the appropriate cam selection.

This guy would be making more HP with the smaller SU carbs.

Its a waste of money to run triple webers if you aren't going to use a cam that can exploit the increased airflow capability.

 

Later,norm

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i am a smog tech and since california changed the test program 3 years ago we have to smog on a dyno.but the dyno has some other features on its menu.like horse power testing.i dont know if the dyno at work is accurate but we got some numbers.most late model muscle cars get about 200 to 220 at rear wheels including 32valve cobra at camaro lt1.my z did 180 at the time the clutch decided it couldnt take any more.my 96 e150 van with 5.8 with a few mods does 170 .another techs dodge charger with 440 did 220.a blow 5.0 stang pegged it .anybody that gets 300 hp to rear wheels in a z has a really fast car.

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Lots of people when building an engine don't consider it as a package that must be built for a specific price, purpose, power, rpm .

 

For example a tunnel ram intake on a stock 350 with dual carbs sux for power and gas milage .

 

I would have loved to see the look on that vette owners face . A small dose of reality to his fantasy world

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Guest Anonymous

Morgan:

Does this mean that, since I considered purchasing your "overhyped" engine, that I am a "purist chump"? I think not. I am quite the opposite, in fact. I do, however, appreciate the simplicity and performance of a stock Z. I would think you just decreased your chances of selling that motor. Hopefully it will work out for you, though.

 

Craig

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quote:

Originally posted by TimZ:

Looks like their club must have had a dyno day. You missed a couple others - a purist car whose only mods were 'period correct' that made ~107rwhp (which is fine - sounds like bone stock was what he wanted), and a nice looking 5.7l V8 that made 240rwhp.

smile.gif

 

Hey! That would be me! http://zccw.org/Club/MembProfile/PaulR/details.htm

 

Yes, our club has put on 3 dyno days up to now. I have to admit, I expected higher numbers for my set-up (Edelbrock Performer RPM heads, cam intake, carb, flat-top pistons, etc). Edelbrock advertises this package at 420HP (flywheel). I'm sure I can get more with some tuning, but 420HP minus 20% for drivetrain loss is about 340HP at the rear wheels... I doubt I'll find that much.

 

I have to admit that I was totaly impressed by a late model Toyota Supra at the last Dyno day we had... over 500HP at the rear wheels! (Big turbo and lots of boost)

 

 

 

[This message has been edited by pricher (edited February 07, 2001).]

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Guest Fast Frog

Hmmmmm!!

 

This guys dyno curves don't look much diff from the original Road & Track test of a stock 76 280Z done in 1976 (I've still got the R&T test results in a notebook). 149 net HP @ 5600rpm and 160ft lbs of torque @ 4200rpm. As a matter of fact his numbers are lower!! frown.gif

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Guest Anonymous

> Does this mean that, since I considered purchasing your "overhyped" engine, that I am a "purist chump"?

 

No craig, because I would have given you a

plenty good price. It would still be easier, faster, and cheaper for you to buy my engine than to build your own practically identical engine.... but it's your money, not mine.

 

> I would think you just decreased your chances of selling that motor.

 

Contrary to what you might think, the entire datsun world doesn't read this web site. I bet less than 0.01% do as a matter of fact. There's plenty of fish in the pond for anything you want to sell. And I'd dump it for scrap metal before I sold it for a ludicrously low price anyhow. That's right, I'll let it rust away before I sell it for $400 or some of the stupid offers I've gotten. The pistons alone cost 2x what some people have offered! So screw them, they can go build their own engine for over 2x the cost/time/work of buying mine.

 

 

------------------

Morgan

http://z31.com/~morgan/s30

http://carfiche.com

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Originally posted by pricher:

Hey! That would be me! http://zccw.org/Club/MembProfile/PaulR/details.htm

 

Paul...

I certainly meant no offense, and was not in any way making fun of your car. The dyno day that I had mentioned had several cars that showed similar results.

 

In fact, I recall looking through a photo album of cars that had been dynoed at this shop. Interestingly, a local AC Cobra club had been there, and there was a photo of the results board. As I recall, I don't think that any of them (many were 427/8/9s) made much over 300rwhp. The 289 Cobras were lucky to get past 250.

 

Just wanted to point out that actual horsepower takes a bit more work than buying some parts (or a crate motor) and bolting them in. And that this is true for more than just the ubiquitous L28 with triple Webers.

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Guest Anonymous

Point taken, Morgan smile.gif Tis true that we had agreed on a fair price.

You are correct that your motor would be a good one IF I had settled on the NA route but, alas, I have recently purchased a turbo (as a big smile spreads across my face). Now the learning process begins! My visit to Scottie's (while in Orlando for business)and the conversation, not to mention the impressive turbo Z owned by Tyler, changed my mind. I came home and bought a turbo within 2 days!

 

Craig

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Guys, you also need to realize that single pull dynos like the Dyno Jet are not very accurate at producing "absolute" numbers. They are good for comparing one vehicle vs. another or one mod vs. another and coming up with relative numbers (most often a percentage improvement).

 

I've seen a racing Viper V10 dyno'd on a Clayton engine dyno product 805hp numbers repeatedly over different days. That same engine in the GTS race car pulled between 605 and 746hp ON THE SAME DAY on a Dyno Jet dyno - with no changes to fuel maps, etc.

 

Clayton recently released an electromagnetic chassis dyno that allows vehicles to do steady state power runs. These are more accurate and much better tuning devices than the single pull dynos.

 

 

 

------------------

John Coffey

johnc@betamotorsports.com

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quote:

Originally posted by Morgan:

Odd that nobody else has a problem with dyno jets being so inconsistant(?)........

It's very simple math and a drum of known inertia - the measurements are very accurate when done properly - ie. no wheel spin, etc.

 

I was thinking the same thing, Morgan. The inconsistency problems that I had always heard of were associated with the non-dynojet dynos, and had to do with eddy current calibrations, thermal drift, etc.

 

If you have a forced induction system, you do have to be really sure that you get the intake charge temps back to the same starting point between runs, or you can see some very large variations in output from run to run.

 

The biggest problem with the dynojet is that it's difficult to get constant load cell monitoring, although it appears that they are developing a method for holding the rolls at a constant speed with a brake, and monitoring the pressure required to maintain the speed. It seems to me that this would have the same calibration problems that the other dynos have, and would only be good for short-term, relative measurements.

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