Horsepower

30 Tudor said:
That reminds me of when I was a young guy fixing my lawn mower. So you mentioned the scavenging effect. That's a real science in two-stroke racing engines. So I thought I would push the limit on a four-stroke.

So I decided to make a race car. I milled the head off till there was nothing left but the valve chamber. Then I had to bore it deeper to make room for the valves to lift 'cause I didn't put a gasket it back on it either--I just glued the head on with coppercoat.

As for the cam shaft, I just ground it on a regular bench grinder and welded the lifters longer so I could adjust it. I made the exhaust open well before the piston was all the way down from the power stroke and didn't close it until it was starting back down on the fuel intake, then it would drop, with lots of valve overlap. Then I put a 21-in. half-inch straight pipe on it for the exhaust. When you finally got that thing started, you couldn't stop it! You could mow as tall and wet and as heavy a grass as you ever saw and it would just grind it up. I mean literally RUN through the yard, trying to bog it down. I tried and tried to just blow that thing up. Couldn't do it. It got to where it smoked pretty bad. I called it Thumper!

You know, that scavenging effect thing works pretty good.:D But you gotta have it revved to the nuts to work! Once it gets there, it's like a rocket!
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Sounds like you built the first Junior Dragster engine!
 
Speaking of scavenging..........In high school my neighbor had a 2 cycle 250 Zundap motorcycle, and one day decided to run it with the exhaust completely removed. It wouldn't even start until he put the exhaust pipe back on.
 
I went to Piranio's page (ModelAparts.net Dyno, Dyno readings) Scrolling down, I found my combination, Snyder's Head, B carb., A manifold bored to B specs (1.250+) No Cam description. No Cyl Bore sizes. Stock must be assumed. Around 52/53 hp. My question is, the HP is given in two readings The HP and the "Corrected" HP. What is meant by "Corrected"?
Terry
 
Terry said:
I went to Piranio's page (ModelAparts.net Dyno, Dyno readings) Scrolling down, I found my combination, Snyder's Head, B carb., A manifold bored to B specs (1.250+) No Cam description. No Cyl Bore sizes. Stock must be assumed. Around 52/53 hp. My question is, the HP is given in two readings The HP and the "Corrected" HP. What is meant by "Corrected"?
Terry
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Imagine if my dyno is located in the mountains, and Dennis' dyno is at 300' elevation. Imagine if my humidity is at 35% and he is at 90%. Even factor in the time of day, the quality of the air, and the temps on that day. My numbers on the same engine would be different than his. Corrected horsepower is a correction standard by which levels the numbers. Realistically, the numbers can still be skewed by the operator, and calibration between machines is generally off. Thus, the info is more for the operator in his R&D than for customer boasting.
 
Yup I'd agree Brent. Only useful to compare cars on the same dyno. Some of them horses can be just ponies. We had half a dozen cars on a new rolling road so had a comparison.

As for the spec of mine, +60, Winfield head, 1.7" inlets, ported, 97 on a snyders manifold, Reds header, and a cam ground by a local stock car racer.
 
1)Brent, Thanks for clearing that up. I think we all fall into the trap of thinking that horsepower is absolute under all conditions now and then. There are a lot of variables.

2) I have to correct one thing I said. That I didn't know what cam grind Piranio's was using. It's a stock grind, I missed it and found it later.

3)In scanning the numbers, I found there is some small improvement in just boring the manifold to B sizes. It's probably barely noticeable when driving but improvement is improvement.
Terry
 
tinkirk said:
Just throwing this out there for idea's.

Whats it take to get one of these little F4's to make more horsepower let's say up there around the 70 number mark?

Thank You in advance
Tinkirk/Terry:rolleyes:
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I have 31 Tudor, changed 3:78 to 3:27 in 2001, 2003 added Brumfield 5.9 head, Mitchell overdrive 26.7 % , Weber carb. In 2008 inserted engine, added cam, installed v8 clutch, took off 26 lbs on flywheel. I have been running electronic ign in both my 29 roadster and Tudor since 2000. Have Aeries muffler , do not run headers. I produce 65 hp on Dyno. Have fun modelAtony Lafayette, LA
 
Terry said:
1)Brent, Thanks for clearing that up. I think we all fall into the trap of thinking that horsepower is absolute under all conditions now and then. There are a lot of variables.

2) I have to correct one thing I said. That I didn't know what cam grind Piranio's was using. It's a stock grind, I missed it and found it later.

3)In scanning the numbers, I found there is some small improvement in just boring the manifold to B sizes. It's probably barely noticeable when driving but improvement is improvement.
Terry
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Terry, the thing you mention that also factors into this is; "who's" stock cam? Even when an original camshaft is reground back to stock lift by grinding off the heal, the duration is affected. Dennis is a pretty sharp cookie, and while I am certain he probably does not remember me, we actually raced together back in the late 70s & early 80s on a match-race circuit called the All American Funny Car Circuit, and in Div 4 Pro Comp. He was making big horsepower even back then.

As for the manifold modifications, the tube size will affect two areas, ...low end and WOT. You would have better throttle response with a stock manifold but better WOT air-flow with an enlarged tube. This all goes back to the golf ball effect.

Listen, this is always a fun topic to dream about, but the practicality of building a high-horsepower engine begins to fade once the numbers start creeping into triple digits. Again, fun but expensive and not for the typical hobbist's car.
 
Oh It is, it is! Lots of fun to fantasize about till one get's the bills. Gee it's still only a 4 banger and without a lot more $ we aren't even going to hit the 100HP mark when the smallest of small SBC starts off with more than that. My problem is that I just want to keep up with the traffic around here. Pa,s got a lot of 1 lane roads with NO shoulders and many of them are either going up a hill or down a hill and the 40 hp sometimes just doesn't cut it. And now and then I have to get out on the Interstate for a couple of miles. That can be exciting! As I don't want to buy the mods that would clearly get me past this dilemma, I am pretty much limited to cheap , invisible mods, like grinding the head (Or getting a Snyder's), porting and polishing, B carburetors. 10-12#s off the fly wheel. So with minimal HP gain my coupes can once again, attack the steeper hills. And I'm thanking Henry for the torque that long stroke is producing.
Terry

Listen, this is always a fun topic to dream about, but the practicality of building a high-horsepower engine begins to fade once the numbers start creeping into triple digits. Again, fun but expensive and not for the typical hobbist's car.[/QUOTE]
 
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My car was clocked going 67 on the flat straights this weekend, and I didn't even have it on the floor, just cruising.
And she's all stock..and fast enough for me.
 
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