2.2 E stroker HP output

[kucharskimb]

some for info. some questions...

i had a 71 2.2E engine with webers. otherwise stock setup, except for an electronic crane cams ignition and coil. when i set up the webers on the dyno, it pulled 143Hp at the wheels.

i later stroked the engine with a 2.4 crank and rod set and added a lightweight flywheel. did some internal mods to a stock muffler, and bumped the weber venturis from 30 to 34 mm. after setting up the carbs, the car pulled 173 Hp at the wheels.

a stock 2.2 E is listed as 9.1:1 and 155 Hp.

1 is there a way to figure out my new compression ratio? i estimate around 10:1.

2 the stock power rating-- is that at the crank, or the wheels?

3 is there a percentage conversion from crankshaft to wheel Hp to convert my 173?

thanks
matt

[jluetjen]

Ugh! That sounds like my middle school Algebra class.

"A train left Chicago for NY at noon at a speed 64 mph. 3 hours later another train left NY for Chicago at a speed of 65 mph. How far will the two trains be from Dallas when they meet" or something like that.

Here's my take on your situation:
1) A stock 2.2E with webers turning 143 HP at the wheels sounds sort of high. Generally Webers produce about 10 HP less then MFI because of the restriction caused by the venturi's. The 30 mm venturi are even most likely a touch small for peak HP in that configuration. I'm not disputinig that you have a dyno print-out with that number, but it seems like the dyno may have been a bit optomistic -- especially if you figure in 15% for transmission losses which would have resulted in a flywheel HP number of 168 HP. It's pretty doubtful that you could find that sort of HP from just the updated ignition and coil.

2) Was the 173 rear wheel HP on the same dyno? That sounds pretty optomistic too since that would most likely work out to about 203.5 HP at the flywheel. That's better then a 2.4S got even though the S had a better camshaft and porting for generating HP, but with lower CR. The lightweight flywheel would not have changed your HP numbers.

I guess I"m saying that the numbers that you're describing don't seem to make sense, unless you take into account that they're biased to the high end for no particular reason.

[kucharskimb]

appreciate the info.

jim mcfarland runs mechtech motorsports (mechtech-ms.com) and has been tuning cars for years. he specializes in off road dune buggies and sees plenty flat sixes come through. he tunes the range of 100 to 800hp vehicles on a weekly basis and is considered a reputible shop in san diego.

that being said. i'm going to stick by my numbers.

pca auto x registration card considers carbs an upgrade, doesn't it?

you bring up an interesting comment about the flywheel...

power = work / time. if you can decrease the amount of time, doesn't your power value go up? wouldn't decreasing your rotational moment of inertia allow you to accelerate faster? isn't that the whole idea of using a lightweight flywheel?

after installing the ignition, i noticed an appreciable difference over the stock cd ignition. definitely smoother idle and acceleration. can't comment on gains, other than after talking with the tech reps, this system puts out about 6 times the spark of the stock unit.

keep the comments coming. i'm stuck overseas, so i'm limited to a little bench racing...

matt

[Mr Beau]

The light flywheel would have changed the HP numbers if using an intertia dyno. We're not talking a lot of gain, but some.

Pics of the dyno plots might help understand what took place as well.

Sounds like fun!

[beepbeep]

Post your dyno graphs please.

173 at wheels mean around 190-195hp at flywheel, which is very good!
Lighter flywheel doesn't contribute anything unless you do your pull in low gears at inertial dyno with light rollers, where powerband sweep takes short time.

[jluetjen]

pca auto x registration card considers carbs an upgrade, doesn't it?

Just because a registration card says that carbs are an "update" doesn't mean that it's an improvement. A correctly set up MFI will always outperform carbs both at the low end of the rev range as well as at peak rev's where peak HP is generated. The big benefit to carbs is that they are easier to tune for obscure and unusual engine configurations and cams while MFI tends to be limited by the programming on the 3D Space cam.

Either way it sounds like you have a great running engine and the extra displacement of the 70.4 mm crankshaft should only make it stronger. Chances are you'll find most of the improvement lower in the rev range since the stock intake porting for the 2.2E will be a limiting factor to the peak HP increasing in proportion to the capacity. It's basically a case of pulling more air though a fixed restriction (the 32 mm ports) in the same amount of time. It just gets harder and harder to do. Note that there was never a stock factory motor which generated more then about 180 HP through 32 mm intake ports. The higher CR will help some to prop up the peak HP curve a bit.

BTW, are you sure that you're not "Double reporting" the transmission losses. You might want to check with the dyno operator if the transmission losses were already included in the numbers that he gave you. The reason that I'm bringing this up is because the numbers that you are reporting are pretty much spot on for a flywheel HP numbers for a stock 2.2E with carbs.

[kucharskimb]

i understand what you're saying about the flywheel. i thought maybe it would make a difference with this being a chassis dyno instead of a engine dyno.

let me double check with jim about the dyno type and if his numbers are adjusted by any percentage for transmission loss.

the torque curve was consistent with the E cams--straight horizontal line. we flowed the E heads on a flow bench and the limiter in this engine is the cam. the heads were good for well over 200hp.

i went back and looked at the PCA card. i misread it. it says carbs and mfi are an upgrade to cis/electronic injection.

anyone have any way to figure out the compression ratio?

i'm currently deployed in iraq. if i can get the plots sent to me before i get home, i'll post them soon. otherwise, i'll update the post when i get home--about 3 weeks.

either way, look for another post after the weekend. thanks for the replies.
matt

[kucharskimb]

gents

got a reply back from jim mcfarland. didn't comment on the type or brand of chassis dyno. only that it is sae calibrated and corrected for temp, altitude and barometric pressure. run was performed at 600ft msl, which has minimal effects...

he said numbers reported ARE numbers at the wheels, and there are no built in adjustments/corrections for drivetrain loss.

the graphs will have to wait til i get home in mid sept. sounds like the scanner at home is kaput and the wife was getting frustrated with it crashing the computer...

i'll post to the same thread. if i can, i'll make the subject "... with dyno graphs".

there was some doubt raised about the effects of an aftermarket ignition. i calculate a stock 2.2E to have 131 at the wheels, where mine pulled 143hp. (i'm disregarding any degradation from the mfi to webers switch)

has anyone else seen marked improvements with an aftermarket ignition and coil? i'm using:

crane cams XR3000
PS1 coil
Jacobs wires
Copper plugs gapped at .045

matt

[Paulporsche]

Matt,

Will you be using this car for autox only, or for street use too? What fuel/octane are you planning on using for your 10:1 CR?

[West]

I run a 2 liter Alum. block with S pistons, E cams and Zeniths. I also put a Crane ignition and high output coil on and noticed a big difference in power over the stock unit. To tell you the truth, I think my 2 liter out performs the 2.4 - t motor that I took out! It may not have as much on top, but it makes up for it in low end torque.

[911ctS]

Sounds like you've got quite a powerful engine there. Are you still using E cams? If you kept your E pistons from the 2.2 and only used 1 cylinder base gasket then I would imagine your compression is more like 9 to 9.5.

I pretty much have the same engine in my car except I used 2.2 S P/C. The heads are stock and the venturi's are 32mm. The best dyno results I have gotten so far is 155 hp to the rear wheels and 154 ft/lb or torque. Im now pondering some mild porting and a new cam grind to get me into the 160's. Good luck with the engine and keep us posted on any new improvements.

[kucharskimb]

paul porsche: premium high octane pump gas. i would like to start doing some autox this fall when i return. but it's primarily a street car.

west: i'm a big believer in the electronic ignition. have you thought of pulling some numbers off a dyno? best $135 i've spent on the car...

911cts: yes, E cams, E pistons, E heads with one gasket. i've heard 9.8:1 thrown out there a lot. i know the formula for determining CR, but i don't know if the longer rod length changes the distance the piston travels on the combustion chamber side, or if the combustion chamber stays the same size. would it be half on top, and half at the bottom of the stroke? it makes a huge difference in the equation.

careful with the porting. you might be able to bump up the hp at the top end, but the bottom will suffer. if your street/autox, might want to save the bottome end torque. based on west's reply, i wonder if you could get there with the ignition upgrade. are you using stock?

i'm using 34mm venturis, but you probably get better throttle response...

thanks for the replies
matt

[Scott Clarke]

Matt-
The combustion chamber volume at TDC will be the same regardless of short or long stroke rods/crank.
-Scott

[jstobo]

The 155 hp number for a stock 2.2E is DIN HP not SAE. The SAE number was about 175hp. If the Dyno is calibrated in SAE then his numbers are probably right. Just a thought.

[kucharskimb]

gents
scanner is completely hard down. i was able to take a pic of the page though...

turqoise line: 2.4 torque 152 @ 5000
purple line: 2.4 Hp 172 @ 6100

pink line: 2.2 torque 129 @ 5100
red line: 2.2 Hp 143 @ 6000

enjoy
matt

[}{arlequin]

cool. thanks.

[rdane]

The dynojet machines run a corrected SAE number. All that inof is on the bottom of your graph.

Nice engine BTW.

[ttweed]

Originally posted by jstobo
The 155 hp number for a stock 2.2E is DIN HP not SAE. The SAE number was about 175hp.

HP(DIN) = 0.9861 HP(SAE), so 155DIN = 157.18SAE, not 175. There really isn't all that much difference between DIN and SAE (less than 2 HP per 100.)

TT

[kucharskimb]

tom
you're right. i misread the number before thinking it was a 1.139 conversion, when it is actually 1.0139...

DIN Horsepower
This is a standard, DIN 70020, for measuring horsepower that very closely matches SAE net. The conditions of the test vary slightly, but the required equipment on the engine and the point of measurement (flywheel) remains the same. Because the test conditions are so similar, it is safe to divide DIN horsepower by 1.0139 to arrive at SAE net. This value is so close to equal that for all but the most technical purposes DIN and SAE net are interchangeable.

that actually means that i'm putting out max hp (200 crank hp) which is higher than a stock 2.4S ( 190 crank hp)...

anyway... the car pulls great!