First Dyno ... Expectations? Tips?

[mca]

I signed up for a dyno test on Saturday December 13th. As far as I know I get three runs. A local shop is doing the tests for PCA members - not sure about what type of dyno is being used but I will find out.

So, what should I expect? Is it common practice for shops to allow timing or mixture "tweaking" in between runs?

I am a tad anxious since I recently rebuilt the engine about 2400 miles ago - 9.5 JEs, 964 cams (advanced cam timing), SSIs, and 2 in 1 out Dansk sport exhaust. Hopefully I will be able to walk away with a smile and not a frown.

Also, with advanced cam timing giving more power to the lower RPM range what kind of torque and hp curve should I expect?

Any input would be appreciated.

Thanks,
Craig

[the]

Originally Posted by mca

Hopefully I will be able to walk away with a smile and not a frown.

Best, then, to do like Obama and lower your expectations.

[Scott R]

My first was bad, but they got better. You can search my name for some experience.

[Superman]

I think I can offer an educated guess. I refreshed the engine in my '83 SC (rings, valves, bearings, etc.) and added 20/21 cams. Stock pistons for that engine (and yours) are 9.3:1 CR. 20/21 cams are similar to 964. They are sometimes referred to as "964+" cams. Your pistons would probably flow better than my stock ones ('turbulence' pistons made for CIS efficiency).

There was at least one Carrera (3.2L) there, and a couple other SC's, some with minor goodies. I am proud to report my car was the strongest, by a hair. I believe it came in at 174 lb/ft at the rear wheels, which is about 205 at the flywheel with 15% drive train loss. Yours may very possibly make more power than that, but don't expect 250.

The dyno guy kept staring at the printout showing my power curve. He said if he didn't know different, he'd swear the printout came from a V8. The power curve looks like a pool table. Pretty darned flat on the top, from about 3800 to about 5500. At least, that is my hazy recollection.

Certainly fun to drive. Put plenty of air in your tires.

Oh.......my ignition timing and mixture setting had been adjusted by The Master (John Walker). He likes to dial in a slightly richer mixture than the very lean stock spec, and he advances the timing to 35 degrees at full advance, if the engine will tolerate that. Some don't. Mine did. The advanced timing makes a fairly big difference.

[Superman]

And be sure your engine is ALL warmed up. I was the first in my group to get on the dyno, shortly after we arrived.

[mca]

Originally Posted by Superman

And be sure your engine is ALL warmed up. I was the first in my group to get on the dyno, shortly after we arrived.

Thanks for the info. Great stuff.

I was wondering about the warm up too. It would be nice to get a "heads up" before my turn so that I can take it around the block a few times.

I am certainly not expecting 250. I'd consider it a victory if I could get 200 out of it.

[84CarreraSC]

Would that be the dyno day in W Ashley; I think the shop is on Belgrade off of Wappoo Rd? I was thinking of going just to watch; I already know how slow mine is.....

[JeremyD]

check your fluids - take your video camera and enjoy yourself. Most dyno shops I have had experience with are complete professionals. Take a thumb drive or blank diskette to get your "runs" on disk. especially if it's a dynojet 248. Then you can get very accurate A/f ratios.

If you pay full price you are probably OK to do tweaking between runs. On a dyno day - you typically are on then off - more assembly line and you won't have much time for tweaking - but it never hurts to ask.

Post results.

[jtkkz]

The person doing the dyno, will check oil etc.... it can get loud depends on your exahust, bring ear plugs

I got mine dynoed recently.

[dfink]

Your first dyno run you will probably think the thing is going to blow up. High revs and full load make a bit of noise. As stated have perhaps a bit extra air in the tires. This is to keep them from getting to hot. Have an idea of how high you want to take the RPM they will program that into the dyno. If like I the ones I have done, when you hit the limit let off the gas, clutch in but do not use the brake. The dyno will coast down by itself.
If it is mustang dyno don't get discouraged by the numbers. A mustang will read considerably lower than a dynojet.

[Facey]

its tons of fun... i went right after a rebuild 3.5L (100mm P&C +46mm webers, early mod s cam, crank fire ignition, twin plugged, etc..)

made 265 hp or something... not bad.... but then around 4000km later, with a few other minor changes, including another carb touch up/jetting) laid down a cool 278.






i'd like to get it back there now... switched the B&B's for georges european racing headers, and a newer M&K.... feels like it has a little more up top... might be that last 2 hp (actually 2.2) to clear 280..... but the number is not what matters, the fun factor is what counts!!!!... i've been told that taller manifolds, and potentially some more cam (missing info to do it safely) could be needed to get everything out of what is out there.

carbs make crazy noise.

[afterburn 549]

Now I feel all warm and groovy with 155 Hp and same tq. @ the rear wheels with my 2.7 CIS 8.5 to 1 CR !! Ever one else said it was low.......................
I do not know what to belive, think I will call Doc Phill

[Facey]

150 is around accurate for the 175 engine hp from the factory...

[RoninLB]

Originally Posted by Facey

its tons of fun... i went right after a rebuild 3.5L (100mm P&C +46mm webers, early mod s cam, crank fire ignition, twin plugged, etc..)

made 265 hp or something... not bad.... but then around 4000km later, ....... laid down a cool 278.

carbs make crazy noise.

how about posting the torque and hp curve for both hp's sheets ?


nice car

[mca]

Originally Posted by 84CarreraSC

Would that be the dyno day in W Ashley; I think the shop is on Belgrade off of Wappoo Rd? I was thinking of going just to watch; I already know how slow mine is.....

Yep, at Autometrics. Should be fun. I think there are only 3 of us currently signed up.

[mca]

Originally Posted by JeremyD

If you pay full price you are probably OK to do tweaking between runs. On a dyno day - you typically are on then off - more assembly line and you won't have much time for tweaking - but it never hurts to ask.

Yes this is a dyno day - 1/2 off normal fee. Maybe they will be more lenient with tweaking if there are not a ton of participants.

[Superman]

Your expectations are realistic.

Changing timing is a snap, but changing A/F is not as quick or easy. I simply took mine to John Walker, who set those things according to his knowledge and experience, and I don't think I could get much more power than he did. Again, he targets a specific sniffer reading and 35 degrees full advance if that particular engine will handle it without knocking.

My dyno sheet was imaged and posted here. Do some searches. I think "Rdane" posted my sheet here, years ago.

Engines run better the hotter they are.....up to the point where the metal becomes soft.

[mca]

Originally Posted by Superman

Your expectations are realistic.

Changing timing is a snap, but changing A/F is not as quick or easy. I simply took mine to John Walker, who set those things according to his knowledge and experience, and I don't think I could get much more power than he did. Again, he targets a specific sniffer reading and 35 degrees full advance if that particular engine will handle it without knocking.

My dyno sheet was imaged and posted here. Do some searches. I think "Rdane" posted my sheet here, years ago.

Engines run better the hotter they are.....up to the point where the metal becomes soft.

I have my AFR at 3.0CO right now. I know JW suggests 3.5CO for non-02 sensor CIS. It would be ez for me to get it to 3.5CO since the LM-1 is dead on accurate with a local shop's sniffer. Recently I had a shop set the CO and then compared it with what the LM-1 was telling me.

My concern is having it too rich to the point where it isn't making all of the power that it could.

I will look up those dyno sheets. Thanks for the input. You are lucky to have JW!

[mca]

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

spam

[Facey]

I have paper copies as i've switched cpu's more than once, as well i've posted the 260 something before, the 278 was on the wall in the shop i worked at the the summer (highest n/a hp, its an import shop, everything is turbo, or vtec..lol)

local pca members have seen the sheet... there is some real nice meet above 3500rpm and the torque doesn't let off until right before 6000 and slowly for the first little bit...
by playing with the timing i as able to get 8 more hp, can see it between the runs, torque curve was getting broader and broader