Opel Dyno Day in Tennessee!!9-29-07

[opelspyder]

I talked with my father last night about getting me a list together. It will be a couple days. We did get some info from Land and Sea. We could have instead of running our numbers in 4th (1:1 Ratio) We could have run them in 3rd gear, due to lesser horsepower cars. The curves will show the best in that gear, and it would have accounted for a higher horsepower number, maybe up to 5 more HP. They were all fairly consistent in 4th gear when comparing, and that is really what the Dyno is about. Every dyno will read differently. DynoJet numbers are always higher (They like to make the customer feel good). But the end result is to do some tuning, and test again on the same dyno. We did a couple of cars in third for some test, and we were getting some 67s and such. I will post a list with names and cars, and I will try to see if the graphs are downloadable into a format I can post here.
Keith

[RallyBob]

Originally Posted by opelspyder We could have instead of running our numbers in 4th (1:1 Ratio) We could have run them in 3rd gear, due to lesser horsepower cars. The curves will show the best in that gear, and it would have accounted for a higher horsepower number, maybe up to 5 more HP.

True, but it's still generally the most accurate with the ratio that is closest to 1:1. Some cars with low HP/torque can't even turn the rollers on some dynos in top gear (Mustang dyno and Dynojet are good examples), since the rollers weigh about 2800 lbs. So the only option is to dyno in a lower gear. But to compare a before and after mod, you need to dyno the car in the same gear every time.

[Tru-Craft]

Originally Posted by RallyBob True, but it's still generally the most accurate with the ratio that is closest to 1:1. Some cars with low HP/torque can't even turn the rollers on some dynos in top gear (Mustang dyno and Dynojet are good examples), since the rollers weigh about 2800 lbs. So the only option is to dyno in a lower gear. But to compare a before and after mod, you need to dyno the car in the same gear every time.

So Bob, what good are these numbers to us?
On a "X" Dyno here in Florida, if my GT shows 100 rear wheel HP, the numbers mean nothing to you testing on a "Y" dyno in the high elevation north, that shows 80 rear wheel HP.

The Dyno is only useful to compare changes made on the same day!
If I changed my timing & carb jets, and I gained 3% in HP/torque, that's the only thing that matters.

I can't say my GT puts out 20 more HP than your GT!
Unless we test on the same day and Dyno.
Bob, what dyno did you test on?
Lyle

[RallyBob]

Originally Posted by Tru-Craft So Bob, what good are these numbers to us? On a "X" Dyno here in Florida, if my GT shows 100 rear wheel HP, the numbers mean nothing to you testing on a "Y" dyno in the high elevation north, that shows 80 rear wheel HP. The Dyno is only useful to compare changes made on the same day! If I changed my timing & carb jets, and I gained 3% in HP/torque, that's the only thing that matters. I can't say my GT puts out 20 more HP than your GT! Unless we test on the same day and Dyno. Bob, what dyno did you test on? Lyle

Lyle, you are absolutely correct. Unless it's the same dyno, in the same place, on the same day...you can't compare 'your' numbers to 'my' numbers.

A dyno is simply a tool. If I start at 100 hp, and with some tuning get to 110 hp, then I made a gain. And that's all that matters.

You CAN compare amongst the group of cars that attended the dyno day of course, but that's about it. We had a similar situation at Carlisle a few years ago, when we tested 5 Opels on the same dyno, one after the other.

I have tested Opels on a Mustang chassis dyno, a Dynojet chassis dyno, and a Dynapack chassis dyno (actually attaches to hubs, taking the wheels/tires out of the equation). I have dynoed engines strictly on a Land & Sea engine dyno, but know of two other Opel guys that have dynoed on Superflow engine dynoes using my parts. It gives me something to go by anyway.

What is nice is I have also dynoed some of those same engines from the engine dyno on the chassis dyno (installed in a car of course!), so I got an idea about accuracy after doing a coast-down test.

Example: One 2.0 engine made 113.9 hp at the rear wheels, and the coast down revealed 14% driveline losses (Getrag 240 and standard rear axle with synthetic oils). So that is assuming about 132 hp at the flywheel. The actual engine dyno results were 136 hp, but that was with no air filter at all (but a full exhaust was in place). So, they're pretty close considering the fact they were dynoed months apart. It all depends on the correction factors in place, and the operator. We always did 15 second pulls. They sound excruciatingly long, but the results were repeatable. Quicker 'flash' pulls might show higher numbers, but were not particularly accurate.

Bob

[opelnut10]

Dyno's are a great tool for tuning to achieve maximum results with your set up. Simple changes such as timing, valve lash and carburator tuning will show up in gains or loses on the dyno tests. To get the best results without changing components, several pull should be made in the same enviorment on the same day and with the same operator. I have seen timing and valve lash adjustments pick a motor up as well as carburators and jetting. When you have to operate within certain allowable engine modifications, spent a day at the dyno can be money well spent providing detailed notes are kept on the dyno sheets as to the changes that were made on that pull.

[Tru-Craft]

Thanks, good info!
Since the rollers weigh about 2800 lbs. a low HP car like are Opel's will struggle.
It's like pulling a trailer up hill!

I will be looking for a local Dyno shop this month.

More questions:
What make of Dyno should I look for?

Should I use the Dyno the "Rice Rocket" Honda guys use?

Should I test in 4th top gear only?

Should the engine be warmed up, before the pull?

Should rear tire air pressure be raised, because of strapping down?

Air cleaner off?

Thanks
Lyle

[hrcollinsjr]

Originally Posted by Tru-Craft I will be looking for a local Dyno shop this month. More questions: What make of Dyno should I look for? Should I use the Dyno the "Rice Rocket" Honda guys use? Should I test in 4th top gear only? Should the engine be warmed up, before the pull? Never place any more load than you have to on a cold engine, if you care anything about it. Should rear tire air pressure be raised, because of strapping down? Air cleaner off? Type of air filter: Open element or cold air intake? Thanks Lyle

I'll let someone more knowledgeable answer the rest.

Harold

[opelnut10]

If you are going to test on a chassis dyno with a road car, you need to run the pulls under road conditions, air cleaner on, tire pressure at proper inflation and engine at operating temp. You are trying to make improvments over a broad RPM range as far a torque and HP and the brand Dyno really dosn't matter as long as you make several pull after you make a base line pull. Make notes of changes in jetting, timing and valve lash on the dyno sheet for each pull when they are made. Also on a road car exhaust size and lenght can effect HP & torque. I have only ran 1 road machine on a chassis dyno and it was not an Opel (70 Buick GSX) and we seen as much as 25 HP and 30 foor pound of torque with changes, but that is a much larger engine (455) but the principal is the same.

[jeff denton]

The advice we see given here looks very much inline with what I've learned in my studies. The article in Hot Rod Mag a couple years ago really emphasizes that the dyno operator really has to know his stuff, so experience and professionalism is what you want to pay for! I hope you get this, and will be able to see how helpful it can be.

[opelnut10]

If you are ever in the Charlotte, NC area and get the chance to tour a top running NASCAR shop, by all means do not pass up the chance.They are not going to let you watch assembly or dyno testing (you might be a spy) but you will see the dyno "cell" (s) and if you take notice they are enclosed and the enviorment is controled as to temp. and air density. Both the Chassis dyno(s) and the engine dyno(s) are in enclosed controled rooms. Once upon a time the "good old boys" kinda flew by the seat of their pants and there was a lot of trial and error on the track, but since it has become big business and big money these guys "ain't playin" and they use every tool they can to make engines live and produce power. You can kinda take an educated estimation as to what will work and what won't, but the dyno will give you the chance to actually have documented results of any changes made.

[RallyBob]

Originally Posted by Tru-Craft What make of Dyno should I look for?

The brand doesn't matter as much as the shop's and operator's reputation. A well-kept, calibrated dyno and an operator who understands altitude and air correction factors is more important.

Should I use the Dyno the "Rice Rocket" Honda guys use?

Should be fine.

Should I test in 4th top gear only?

This will be more accurate, yes. You won't have the gear multiplication changing the torque numbers. This is a common shop 'trick' to let a car owner *think* they made a big change in power. First dyno in 4th gear, second pulls after mods in 3rd gear!

Should the engine be warmed up, before the pull?

Yes! Full coolant and oil temps are critical! It's like making a high top speed run, so lots of stress on the engine.

Should rear tire air pressure be raised, because of strapping down?

Run your normal pressures, and make sure they're equal side to side.

Air cleaner off?

Only if you're doing a lot of jet changes, as it makes the tuning easier. But in general if you want the 'real world' numbers, leave it on. A bad filter design can affect air/fuel ratios (just like on a motorcycle).

Bob

[Tru-Craft]

Thanks again for the info!
I will have to add all this stuff to my Dyno test sheets.

I will start searching for local dyno shops next week.
Like you guys said, a good skilled Dyno operator is probably more important.

My drag racing neighbor is going with me, he has had experience with chassis dyno's.
Lyle

[RallyBob]

Originally Posted by Tru-Craft Like you guys said, a good skilled Dyno operator is probably more important.

You got it, just like in your profession Lyle...what good are your machines in your shop without a good operator? A bad machine operator/programmer with the lastest 5-axis CNC machinery can do a lot of damage, but a good machinist on 50 year old manual mills and lathes can make virtual jewelry.

[BrettB]

Tony, Glad you got some footage(orange GT) of Swifty, my 71 orange gt automatic that dynoed right up there with Bear's and Matt's very nicely restored GT's. Matt, as I was living I asked Denise if ya'll wouldn't rather have an orange automatic but that was my fantasy----:-) !!!! Keith, a big thanks to you and your father and your lovely wife(for putting up with us) for a great day in Tennessee! I really enjoyed meeting some of you guys like Gene and Dieter that I see post a lot. Up till last saturday, it was mainly keith and Harold that I talk to ( God, i got to get out more often ;-) !!!!

[opelspyder]

Here is the list of the final stats

[hrcollinsjr]

So does this mean that you haven't figured a way to post the horsepower and torque curve graphs?

Harold

[greenopelgt]

TO: All that attended Dyno Days

I just received in the mail a signed Dyno Days T-shirt with your individual comments. I sincerely appreciate and will value this act of thoughtfulness from my many friends in the Opel community who took time out of their special time together to think about someone else.

[BQS4]

Originally Posted by greenopelgt TO: All that attended Dyno Days I just received in the mail a signed Dyno Days T-shirt with your individual comments. I sincerely appreciate and will value this act of thoughtfulness from my many friends in the Opel community who took time out of their special time together to think about someone else.

Tom;
You're welcome!!

[opelspyder]

Tom, we just appreciate having you as an Opel Brother. We all feel bad about what happened to you, and wanted to send you something.
Keith

[Gary]

Originally Posted by opelspyder Here is the list of the final stats

Here they are in PDF format: