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Author Topic:   Dynamometers - Need general info
rickbraley
Member
posted November 09, 2004 07:28 AM
I need to get a baseline measurement on my engine's power output and I was hoping some of you may have some insight on the following:

Chassis vs. Engine - is one more accurate than the other, what are the pros and cons of each?

How much parasitic loss can I expect to see through my drive train (Bert, Ford 9")?

Can you recommend anyplace in the KC area that provides this service?

Thanks.

[This message has been edited by rickbraley (edited November 09, 2004).]

zeroracing
Member
posted November 09, 2004 08:04 AM
chassis vs. engine: either one is good. Chassis is usually a little cheaper and faster. You drive in, setup, run, drive out. Engine dyno can take all day or longer by the time you setup, run, then cool down before removing it.

Though a bert and 9" ford i beleive you will lose about 15% in the drivetrain. Not sure if that is with synthetic lubes or not or any other details but just a rough number.

Either one will help you set timing and fuel. With the chassis you will be able to see exactly what your putting to the ground. We did an engine dyno once, and if i were going to do it again I would prob think about doing a chassis just because it seems easier and is cheaper. Only downside is if you want to make big changes to the engine its already in the car. But with the cost of dyno time its not very feasible to do that anyway.

I think there is a chassis dyno in Overland Park somewhere. Get on dynojets website and you can search for locations. I cant rember what they said it would cost. Seems like if you scheduled a time in the weekdays it was like 150 for 3 pulls then 75$ per hour after that or something. I'm know there are engine dynos around too, but I dont know of any of the top of my head. Then you are looking more like 750$+ plus fuel for the day but that includes setting up and if you dont want to leave your engine overnight it willhave to cool 2-3 hours before you remove it, So in the end you may only get 4 hours of dyno time anyway.

[This message has been edited by dirtbuster (edited November 09, 2004).]

NJantz
Member
posted November 09, 2004 09:17 AM
There are 3 dynos that I know of in KC - the oldest one is up at MC Racing - there is also one down south that I can't recall the name and there is a shop in Lee's Summit that is supposed to be getting a 4-wheel / AWD dyno. Try http://www.gomcracing.com

Really the debate over which one to use is a moot point if you ask me - who cares what the loss is in your drivetrain - unless you're going for bragging rights (then have the operator 'cook' the numbers to look better...) - I'd just concentrate on laying down a baseline run, then adjust carburation (a/f ratio and throttle response) and timing until the best power is made in reference to your baseline. It won't matter if the baseline said 400hp at the wheels or 300hp at the wheels - when you see an improvement in the right direction that's all that counts... you're not going to be swapping cams, swapping heads, etc. - just minor jetting and timing changes to extract the most of what you've got.

As for the cost - figure around $75-80 for a baseline run and then around $100-125 an hour for tuning runs. Figure 2-3 hours to get an engine dialed in...

Kromulous
Member
posted November 09, 2004 10:25 AM
Also i would think that a Chassis dyno would be good for help on getting the gearing right for your track.

Show you your actual power band of your entire combination so you can adjust it to meet your needs.

rickbraley
Member
posted November 11, 2004 07:13 AM
Thanks for the info!

How did you guys come up with the 15% & 18% parasitic loss percentages? General rule of thumb, intelligent guess or actual measurements?

I found a place with a Chassis Dyno. The business is names Supertune Performance Center. They are located at 162nd & Metcalf. Really nice people and the facility is top notch. There number is 913-814-7243. Ask for Christi and tell them Rick Braley sent you.


dirtbuster
Member
posted November 11, 2004 07:46 AM
I think my 15% number came from sdhnc29 and his dyno experience. I think he said brinn and 9" was 15% while brinn and quickchange was 18%. Either way 15-18% isnt much compared to some of the other tranny options out there.


NJantz
Member
posted November 15, 2004 11:50 AM
Do you guys have an opinion on how much power is required to be competitive on say a fast 1/2 mile track? I have talked to lots of other racers and it seems the magic number that I hear is 600HP. I also assume that is at the crank and not the rear wheels. And yes I know it is not all about HP but this is a key factor in the equation...

Any feedback?

[This message has been edited by rickbraley (edited November 17, 2004).]

Kromulous
Member
posted November 17, 2004 02:07 PM
UMP, definately 600hp, in the car and in the dead of summer with high humidity, not on a dyno @ 70 degrees F.

700hp would be more like it, smooth power but you could use on some tracks.

IMCA, i have no idea or any other sanctions for that matter. Although i would imagine USMTS is much the same as UMP.

700hp range would be my goal for any new engine that would go in the car now days.

zeroracing
Member
posted November 17, 2004 02:10 PM
zero is right about lakeside. If you show up with less than 600HP you better hope its one of the rare nights it gets dry (or at least drier than normal). On the other hand i know guys that have one USMTS races on smilar tracks with 560HP.
I would say depending on the track and track conditions. 570-600 would be a good number to shoot for. There are a few tracks that can use 650-700 but i would say there are more where 550 is enough. Wind up somewhere in the middle and you shouldnt be too far out.


rickbraley
Member
posted November 18, 2004 08:31 AM
Thanks for the info. Yes, zeroracing you are correct that I do call Lakeside my home track. Sounds like you run out there too? What car are you with? Last year was my second season in a mod (came up from a mini-sprint) and we ran the whole season there. I really like the place(cheap plug for Lakeside) .

I am just trying to get a handle on things. My team (Mark Paris and myself) do it all. We build our own engines; assemble our cars, etc so as you probably already figured out I am trying to see what we need equipment wise to be serious contenders.

In general what engine configuration do you guys think it takes to get to that magic 600HP level? I am currently a little short of that number and am trying to figure out what I can do during this refresh to get it up there another 50 - 75 HP...


dirtbuster
Member
posted November 18, 2004 08:38 AM
What is your current combo. Give us some details and we'll go from there.


rickbraley
Member
posted November 18, 2004 01:36 PM
Let's just assume that you could buy any parts you wanted. What would you buy to get 600HP and stay within the limits imposed at Lakeside (i.e. 410 ci, 14.1 max compression, all steel, etc)?


dirtbuster
Member
posted November 18, 2004 02:17 PM
If it were me I'd go 377 with a dart or bowtie block. Good steel crank and rods. and JE pistons. Keep compreesion up around 13.5-14:1. For heads i'd look at Dart Iron eagles 230cc. With a good roller cam that combo would make close to 650HP on alky, and i'd plan to turn around 7700rpm or so. You could go 406 and pick up some torque then not turn it so hard if you wanted, but i like the shorter stroke for high rpm stuff. Either way at this level you dont want to chance it with bargain parts. You need good stuff if you want it to hold together.

If money was no object you could look into PRO 14 degree steel heads. Quite abit more expensive and they require offset rockers and a different intake but would make gobs and gobs of HP.