Dyno testing

[Armand4]

Hey everyone!

I'm taking my Alpine for a dynamometer test tomorrow. Well, really, I'm taking the Alpine in order to participate at a barbecue at a friend's race shop, which is tied in to a race series where I work. I figured a dyno pull would be fun, and perhaps help me get the car running a little bit sweeter. Here's a link to a forum posting about the party: http://forums.24hoursoflemons.com/viewtopic.php?id=2843
Yeah, I know, an Alpine isn't about the numbers-- it's about the driving experience. But I'm curious to know if anyone else on the forum has dyno'd their (mostly) stock Alpines, and if so, what their cars put down.

Keep your fingers crossed for me and my car-- we'll be trying to put down more power than my friend's MGB!

 

[RootesRacer]

I'd say if the dyno tells you you put down 70hp SAE to the ground, you are doing pretty well for a stock 1725.

What type of dyno are you going to be using?
Some dynos show inflated numbers, while others are low since they dont take into account rolling losses.

 

[Tullamore]

I take a car down to test on a Mustang Dyno every year, I haven't gotten around to doing an Alpine yet but I will soon.

Here is the graph from my completely stock Tiger:

 

[SIVAllan]

I'd say if the dyno tells you you put down 70hp SAE to the ground, you are doing pretty well for a stock 1725.

What type of dyno are you going to be using?
Some dynos show inflated numbers, while others are low since they dont take into account rolling losses.

Airpine measured at 70 bhp on a dyno with a fresh 1725 and Zenith WIPs.

I hope to upgrade the top end this year trying to pick up 15 - 20 bhp. Might be wishful thinking, I dunno, time will tell.

Also I forgot the redline, told them 6,000, so I now know the motor is good to that RPM .

 

[RootesRacer]

You will need webers to get your 15 to 20 hp.

This puts you about 100 to 110 crank, and realistically neither the stroms nor the wips will support that HP level.

You may pick up 10lb ft of torque, maybe even 10 extra HP on the top end, but the 15 or 20 is going to cost you...

 

[SIVAllan]

You will need webers to get your 15 to 20 hp.

This puts you about 100 to 110 crank, and realistically neither the stroms nor the wips will support that HP level.

You may pick up 10lb ft of torque, maybe even 10 extra HP on the top end, but the 15 or 20 is going to cost you...

I have a weird motor

It has a Holbay head (rebuilt by Jim E ), and flat tops from Coltec/UK. Weird, huh?

I planned to include dcoe40's off a Hunter GLS, a Bill Atalla header, and a Redline intake but alas! those parts were destroyed in a fire.

But they will be replaced and installed this year...changing the top end considerably.

Last mod will be a KB grind camshaft.

Maybe those mods will help generate the 15--20 bhp....

 

[RootesRacer]

I have a weird motor

It has a Holbay head (rebuilt by Jim E ), and flat tops from Coltec/UK. Weird, huh?

I planned to include dcoe40's off a Hunter GLS, a Bill Atalla header, and a Redline intake but alas! those parts were destroyed in a fire.

But they will be replaced and installed this year...changing the top end considerably.

Last mod will be a KB grind camshaft.

Maybe those mods will help generate the 15--20 bhp....

Yeah put the webers in the mix and 15 to 20 is well within the realm of possibility.

My 1725 "mild" engine runs a 275 cam and webers and dynod above 100whp.

I think the KB is a bit milder than my 275 cam, but with some compression and the head mods you should be able to equal if not better my numbers.

 

[Armand4]

Around 70 at the wheels for a healthy 1725, eh? My motor is a 1592 with a Weber 32/36, one of Bill Atalla's headers, and a free-flowing (or, at least, loud) exhaust. I'm sure that, even with those mild tweaks, it won't approach the performance of a 1725; we'll see what she'll do.

It looks like my MGB buddy is probably going to wind up $20 richer tomorrow... I'll tell him to use the cash to buy a proper car.

 

[RootesRacer]

Around 70 at the wheels for a healthy 1725, eh? My motor is a 1592 with a Weber 32/36, one of Bill Atalla's headers, and a free-flowing (or, at least, loud) exhaust. I'm sure that, even with those mild tweaks, it won't approach the performance of a 1725; we'll see what she'll do.

It looks like my MGB buddy is probably going to wind up $20 richer tomorrow... I'll tell him to use the cash to buy a proper car.

Do let us know how it fairs.

Also dont forget to ask about the dyno mfgr.
I have compiled a list of conversion factors to compare one mfgr to another since some ere more liberal with the truth than others.

 

[Armand4]

dont forget to ask about the dyno mfgr.

It's a Mustang dyno. Here's the race shop's page: http://www.evilgeniusracing.com/dynoservices.html

 

[sunbeamowner]

Had my basic 1725 with a Gt Hunter Cam Dyno tuned last year.
The different figures are
First with a poorly tuned single side draught 45mm Weber (55.8HP).
Secondly properly tuned (69.4)
Next two 40mm Delortos (69.8) and lastly two 40mm Webers (72.4)

 

[64beam]

I take a car down to test on a Mustang Dyno every year, I haven't gotten around to doing an Alpine yet but I will soon.

Here is the graph from my completely stock Tiger:

Hi Steve,

Was that reading on the engine or at the rear wheels? If that is rear wheel Hp, you have one very healthy stocker. Was it 260 or 289?

Regards, Robin.

 

[RootesRacer]

Had my basic 1725 with a Gt Hunter Cam Dyno tuned last year.
The different figures are
First with a poorly tuned single side draught 45mm Weber (55.8HP).
Secondly properly tuned (69.4)
Next two 40mm Delortos (69.8) and lastly two 40mm Webers (72.4)

If you ever go back there, tell them to make sure that they either have the RPM pickup working, or that they have "scaled" the roller RPM calculator.

The HP numbers that it calculated are totally legit, but the roller speed instead of actual RPM is of little help when comparing dyno graphs.

 

[serIIalpine]

I really hope my 1612cc Series II with Light vizzard mod with cleaned up ports and Isky SB2 cam and weber 40s is doing better than 78 hp.

It sure feels like it.

Someday I'll get it on a dyno.

 

[RootesRacer]

I really hope my 1612cc Series II with Light vizzard mod with cleaned up ports and Isky SB2 cam and weber 40s is doing better than 78 hp.

It sure feels like it.

Someday I'll get it on a dyno.

Keep in mind we are talking about wheel HP, not crank HP.

 

[Armand4]

So my engine is a 1592 with many miles and many years on it. As I mentioned before, it has a header and a Weber DGV, but the jetting is no better than "close enough" (there aren't any big flat spots, and the spark plugs are the right color, so I've never fiddled with the jets). I don't know if there are any internal modifications, but I'd be very surprised if there were. And, of course, the engine sometimes makes noises that worry me.

I got the $20 before I even had the car strapped to the dyno-- my friend's MGB blew its engine on the way to the party. I'm not worried-- he's got a whole bunch of B-series engine cores in the back of his garage, and he's a heck of a mechanic, so he'll be all right. But his misfortune meant that engine failures were on my mind as they strapped my car to the dyno. That ticking was normal valve clatter and not a dying main bearing, right? I asked the dyno operator not to take it above 5000 RPM.

I assumed that my "tired" 1592 would put up a number in the high 40s, and we'd have a good laugh, and I'd go home and plan a badass Chevy-rodded, Vizard-headed, flat-top-pistoned monster motor.

The Mustang dyno showed 66 horsepower at the rear wheels of my car. The real revelation was the torque curve-- it just hovers around 70 pound-feet from 3000 to 5000 RPM. I never thought I'd be so excited about 66 horsepower!

 

[alpine_64]

I asked the dyno operator not to take it above 5000 RPM.

The Mustang dyno showed 66 horsepower at the rear wheels of my car. The real revelation was the torque curve-- it just hovers around 70 pound-feet from 3000 to 5000 RPM. I never thought I'd be so excited about 66 horsepower!

So was this 66RWHP at 5000rpm? Was the graph still climbing at a steady rate or was it flattening out?

 

[SIVAllan]

Is there any benefit to a dyno tuneup on a good running 1725 with Zenith WIPs?

All I see as adjustable is the idle for the carbs, timing, and maybe plug selection.

And to check the fuel/air - an O2 port will need to be welded to the exhaust somewhere near the engine.

So that's gonna cost a few hundred bucks.

Might find a couple bhp, I dunno if it would be worth it.

 

[RootesRacer]

Is there any benefit to a dyno tuneup on a good running 1725 with Zenith WIPs?

All I see as adjustable is the idle for the carbs, timing, and maybe plug selection.

And to check the fuel/air - an O2 port will need to be welded to the exhaust somewhere near the engine.

So that's gonna cost a few hundred bucks.

Might find a couple bhp, I dunno if it would be worth it.

You can also adjust the idle and main jets in WIPs, though this will probably have to do with drilling and or brazing and re-drilling the jets.

Timing can make a huge difference on power. Plugs not so much if it runs at all.

If you are handy, there is no reason you cant weld the O2 bung in yourself.

I bought a cheap oxy-mapp torch (home depot IIRC) and it was hot enough to braze a spark plug extention into a hole I cut into the exhaust pipe.

Are you planning on a wideband O2 install?

 

[SIVAllan]

You can also adjust the idle and main jets in WIPs, though this will probably have to do with drilling and or brazing and re-drilling the jets.

Timing can make a huge difference on power. Plugs not so much if it runs at all.

If you are handy, there is no reason you cant weld the O2 bung in yourself.

I bought a cheap oxy-mapp torch (home depot IIRC) and it was hot enough to braze a spark plug extention into a hole I cut into the exhaust pipe.

Are you planning on a wideband O2 install?

I guess I'll go forward then; I am pretty sure the timing can be improved but I don't want to change my Zeniths -they've run fine once I finally got them right and they will be replaced this year by dcoe40 webbers . Might want to use them on a future Alpine

Regarding the O2 install, the dyno guys said they would do it but did not specify what type -- and this is totally new stuff to me.

Is a wideband O2 install somehow better than a (?) "normal-band" O2 install?