R16 Horsepower Curiosity for Stroker and Race engines

[Datsunparts.comInc]

Suggest caution on interpretation of that dyno graph....

First off the displacement is noted as 350 with a 4.03 bore, so we know thats wrong. What else
is wrong and was the dyno even calibrated to any standard? Who knows? As wise man recently said to me "I can make a dyno dusplay just about anything I want"

We know it isn't an R16 at 1600cc if the measurements are even close to correct, so most likely 2.1 or beyond.

The max HP measurements of 180 and 186 are approching 8k, so of little practicality except for racetracks. In contrast Nissan provided measurements at 6k, which is far more useful for street use. So the 6k number matters a lot more unless this is a track engine.

Whats most apparent to me is that until over 7000 rpms, there is NO difference in torque between the two headers... less than 2% which is in the error band of the dyno. So with this engine there is no practical difference between the headers. Rebello proved that fairly effectively and Daryl picked up on it immediately.

And why would there be? The header design is essentially identical. Nothing is significantly different in either pipe configuration or the collector setup. As expected, 1 5/8 primaries start to matter near 8k. No practical difference for street cars.

Lastly, if you go pushing things to the bleeding edge, especially using budget components to make big displacements and try running around at 8k you will sacrifice much of the ruggedness and reliability these engines are known for. When you play on the bleeding edge a lot of times blood gets drawn....

Dave likes the header. It cost a great deal of money to develop. He wanted it and uses it. Dave has built hundreds of engines and devoted his life to engine building and he has notoriety and presence in the race industry. You have conviction though and since you are not a paper tiger I would invite you to call Dave and straighten him out.Read him all your comments. 925-754-4871
http://www.rebelloracing.com/testimonials.htm

[JT68]

There's really no reason to argue about it, the graph shows 2ft-lbs of torque and 6 hp up near 8k for whatever displacement engine this is assuming the absolute accuracy of the dyno. That is what the DATA says.

I agree with you Dean, that's quite in line with what many experts would have predicted. It's of no consequence for a street car.

Have you ever torqued anything to 2 pounds? Its about as minimal as it gets. 1.4% increase by my calculation.

For the benefit of the original poster, lots of 5main 1600cc racing engines will wind up in the 115-130 range. With lots of money and time you can get well into the 130's&140's. Col. Joe Hauser was the first guy to figure out how to make the 3-mains survive at extreme rpm and he was pretty fast. The 3-mains really accelerate well due to far less rotating mass, but he blew up a number of engines figuring it all out.

Really big R/H engines can get past 150,175, 200? maybe if money is no object. The block does have structural bore limitations however.

[Pjackb]

"I know Lou has built an R16 that has about 125hp but 190lbs of torque"

R16 is 97.3 cubic inches.
I'm quite sorry to say that this is highly questionable. Getting 2 hp per cubic inch is hard enough, naturally aspirated, to get near 2 ft/lbs per cubic inch is near, if not, impossible, especially from this engine.
(RPMxT)/5252 = hp

(3500x190)/5252 = 126.6 hp - That is assuming you are limited to 3500 rpm max. As soon as you exceed 3500 rpm, the HP increases....(145HP @4000)

While the math sorta works, the compression required would be in the high diesel territory, if then, not going to work with gasoline. jmo.

Daryl
I have no idea if possible or not just relaying information provided by Lou, since I know he’s done crazy stuff with these engines I didn’t doubt him

This is an excerpt from an email Lou sent me with a photo when we were discussing him building me an engine

1840cc R16 undergoing engine dyno testing. 38 mm Hitachis. Long 4-1 pipes. 120 hp @ 6000. 212 ft/lbs @ 4000.

F74D949F-DFBC-41B5-8A4F-5FC07961FC38.jpeg

He went on to say this

In the R16/H20 crank case, the alloy R16 head is the drawback. The port shape is woeful, I have tried and still am trying to make above 180hp using an alloy R16 head. I have spent over $7000 on this particular project with some interesting results.

[23yrRebuild]

I'd really be interested to know more, specifically, about the cams, and carbs used in these strokers example....I'm not an engine scientist, but I'm given to understand the cam is the heart of where the engine makes torque and horse power. I am planning to schedule a chassis dyno test soon on my stroker, with 9.5 CR, 266 Isky cam, fully stock R16 head, valves, and R16 SU's, 4 into 1 header, and I'll post the results, whether they be impressive, or not so much.

And by the way....For the rest of the stroker owners who haven't entered their build info in the Stoker Section of the Forum, please do so !
Mike

[JT68]

The age old engine builder adage "don't over cam your engine" still holds. Too much cam creates all kinds of problems. "Too much" depends on all the exact specifics of the engine. So its WAY too much to go into here.

These engines are quite responsive to moderate cam increases.

Since we mostly focus on street engines now, I can tell you what Jack/lou posted about the head and power limitation is spot on. The AL 1.6 head/valvetrain is the limitation for either racing or street stroker setups.

[23yrRebuild]

JT: I TOTALLY agree with everything you just said about cams. My research took me deep enough into "cam science" that I chose the 266 Isky, and I think Steve Allen may have used one of these as well, in one of his cars. I can tell you it was a really good choice for what I wanted. Considerably more pep and responsiveness, with a decent idle, power band is relatively wide about 2500 - 6000 rpms if I remember the specs correctly. I don't think I would consider any other mods or additions to my engine, as it runs awesome enough for me, without racing. I would like to obtain a lightened flywheel, though. I think it's probably the last thing that would improve it's spirited personality, without the expense and work of tuning dual choke carbs. Anyone know where I can get or send off a flywheel to be lightened ?

[Pjackb]

Mike , What's really interesting is that when my R16 was rebuilt by the PO it wasn't stroked but got over sized pistons, potentially a mild cam and a slight bump in compression Just that makes for a very peppy and fun engine ,

in the other car i have a U20 with one of JT's Billet flywheels , I'm still breaking in the engine but the only word to describe that flywheel is WOW
Plan for next year is to have him build an R/H Stroker optimized for torque where we drive (2500-5500 rpm) to replace the R16 , should be great with the same flywheel

i'm not aiming for an HP number but I know it will fall somewhere between 125-150 with lots of torque and I know Based on the way the R16 is in my car that it will be fun

[23yrRebuild]

I forgot to mention that I'm also using standard, U20 flat top pistons & rods. Full info is on the Stoker Section. How light is JT's billet flywheel ?
Mike

[JT68]

Pjack has the 10lb.

[Gregs672000]

Keep in mind that the gross hp ratings Nissan used were at the crank and without water pump, alt, etc. I takes a lot to go from 96hp gross to 130hp wheel. The head is the primary limiting flow factor, but only one part of a system. Cam choice is critical for driving style so choose a duration that makes power where you want it and how your drive it. You can also increase lift and keep the same/similar duration and improve performance (be sure to compare duration specs at 50thousands). The more the duration the further up the rpm range you push the peak torque. The more you modify parts of the system the more you will need to upgrade other parts... intake, exhaust, carburetion, ignition control/output. Fine control over timing and fuel become more important. The U20 head was the biggest factor in the power differences in the engines.

[Pjackb]

I forgot to mention that I'm also using standard, U20 flat top pistons & rods. Full info is on the Stoker Section. How light is JT's billet flywheel ?
Mike

Not sure how light it is but I can tell you it makes my right foot heavy

[23yrRebuild]

Hi JT: is that a bolt on for the 5 main stroker crank, and I'm looking for something around the 15 to 17 lbs range that some others are using,....10 lbs sounds awesome for racing, but mine needs to be happier on the street,...LOL !

[23yrRebuild]

Anyone in California familiar with this place ?
https://www.racetep.com/engine-building ... ening.html

[Pjackb]

Hi JT: is that a bolt on for the 5 main stroker crank, and I'm looking for something around the 15 to 17 lbs range that some others are using,....10 lbs sounds awesome for racing, but mine needs to be happier on the street,...LOL !

Mike,
Not sure if it’s because JT put the whole thing together for me but it doesn’t feel like a light flywheel at all clutch take up is really smooth With no jerkiness and there’s good pedal travel I have a LW aluminum flywheel in my Z and that one has a little less travel but still smooth

Both do not compare to the one I had in my E36 M3 , that was not fun had it had about a 1/2 inch of travel and everyone no exception that drove the car the first time stalled

You wouldn’t know I have JT billet flywheel other than the car revs very freely and had a lot of pep


I’ll double check with the PO but The LW flywheel in my Z I believe is from Top End , I still would take one of JTs before that

[bossbob]

Thanks for the input, I was really just curious. I'm not in a hurry to rebuild my engine. But, if or when the time comes, I know I would want to do it right and do what I can to increase the power. With that being said, I don't think I would object to an engine/trans swap as well. Still just trying to get my car on the road, so really no hurry, just curiosity.

Thanks again.