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Posted by: Jetsetsurfshop Feb 22 2015, 12:39 PM

Hey Everyone,
I have a dyno appointment coming up next week. Is there anything that will take me by surprise? The guy running the dyno just said to not forget gas.
I plan on bringing, fuel, straps, fans, and my weber jet kit.
Can anyone thing of anything else required?
What RPM should I stop at? My car has larger valves (48-38), duel valve springs, solid lifters and a 494 webcam.
Heres more info on the car.
2258cc
10.5 to 1 Compression Ratio
40 webers
Tangerine headers
98 octane fuel
What do you think she'll make at the wheels?
Shane

Posted by: carr914 Feb 22 2015, 02:32 PM

Depending on Cam, your Peak HP & Torque will be in the 5500 to 5900 range.

For an Engine Dyno, I've had to supply the Oil. If it's a new rebuild, I would use Joe Gibbs Break-In Oil

If it's at the Crank, 150 hp, At the Wheels, 130

Posted by: Jetsetsurfshop Feb 22 2015, 04:13 PM

Bringing oil is a good call. I'm thinking 120-130hp at the wheels. Anything over that will be a bonus.

Posted by: Jetsetsurfshop Feb 22 2015, 04:30 PM

What gear do you run a dyno in? 4th?

Posted by: Randal Feb 22 2015, 06:45 PM

Seems to me it was third.

Make sure those valves are adjusted!

Pretty exciting time.

Posted by: carr914 Feb 22 2015, 08:02 PM

Dyno Time is Cool unless you are like these guys!

Posted by: carr914 Feb 22 2015, 08:06 PM

Engine Dyno's make for a Cool Day!

Posted by: wndsrfr Feb 22 2015, 09:23 PM

Different dynos give different results, but if you've got things right, you'll be getting near 150 at the wheels I think. Watch the AFR's like a hawk....shoot for 12.5 or so...keep it fat & stay below 13....
You might want to try a run with the air cleaner lids off....depending on how tall your velocity stacks are, the lid on the air cleaner can affect the induction. I found that to be the case on my /6 and installed a taller air filter element to help out a bit.
Max power on my /4 Raby Kit 2316 was around 6000....I had my fuel cut on the SDS injection set at 6800.....here's the graph....93 octane fuel and CR at 10:1....enjoy!

Posted by: Randal Feb 22 2015, 11:16 PM

Pretty

Posted by: ThePaintedMan Feb 23 2015, 12:19 PM

Never been to a dyno, but I understand some of the principles of them. I believe that all dynos are calibrated for a certain RPM (of the roller itself, so that translates to MPH). They'll know what theirs is calibrated for, usually 80-100 MPH. So you want to achieve that speed in the gear that you choose when the motor has run all the way to the end of it's powerband. In most 5-speeds that might be 3rd, but on a 914 gearbox maybe 4th? I'm sure the guys at the dyno can explain that a little further for you. Basically you're looking for accuracy.

Posted by: Racer Chris Feb 23 2015, 01:46 PM

Use 4th gear for your dyno pulls.
3rd will accelerate too quickly IMO.

Posted by: Borderline Feb 23 2015, 02:32 PM

The few times I've been on the local chassis dyno, we always ran in 3rd gear. IIRC, they said it had to do with how long the run took. they were trying to get it to be about 10 seconds. My buddy tells me that the fuel/air ratio will change with the different gears. Higher gears tend to load up the engine more and draws more fuel causing a richer mixture. I'm not sure.....just go with what the dyno operator says

Has the engine been broken in yet? It's hard to break in an engine on a chassis dyno. Make sure you have it broken in before trying to dyno tune it.

Have a good selection of jets and tools to change them quickly. Most dyno guys are used to making changes to your electronic fuel injection and don't have a lot of experience with Webers. You're basically going to be changing main fuel and air correction jets.

Be careful to roll on the throttle and not just mash it down. The accelerator pump will screw up your bottom end readings.

I'm sure there is more......just can't remember it all right now

Posted by: brant Feb 23 2015, 06:44 PM

We always end up using 4th

Posted by: campbellcj Feb 23 2015, 10:44 PM

I'd be surprised if you need your own straps and fans, unless it's a "my buddy just bought a dyno" type of scenario.

Pretty sure my pull a few months ago was in 4th gear. The car was really zinging. Loud as all hell with the open pipes and webers just a few feet away.

Posted by: carr914 Feb 24 2015, 05:47 AM

This!

When I had that Engine Dyno done before, I was in the Control room and could hardly think it was so loud

Posted by: Jetsetsurfshop Feb 24 2015, 02:43 PM

Been working a lot these past few days, forgot to keep up with my post.
I was, and may still be, doing a dyno reading for my TT classification with NASA. I have since talked to the director and theres a formula for my modifications that does not require me to do a pull. So after all that, I may pass depending on what he director says. I might still do it for the fun, but work is busy in Southwest Florida this time of year. (need to make those deposits)
Thanks for the input and if I still go, Ill post the info for all to see.

PS. Engine is broken in (two years on build)
Its not a "buddy with a dyno", I just alway come prepared.
Fourth gear is what we though too.
If it pans out, I just don't want to blow her up!!!

Posted by: wndsrfr Feb 24 2015, 04:27 PM

I'm guessing that you're comfortable with your jetting but interested to know how you determined what to use....do you have a wideband installed?

Posted by: Jetsetsurfshop Feb 24 2015, 04:50 PM

I do. We installed it after I ran it to lean and cracked a piston. I have worked on the a/f ratio after that. I was going to try to "dial it in" more if possible but my dad (read as mechanic) can't go with me. Another reason to wait till summer.

Posted by: wndsrfr Feb 26 2015, 09:22 AM

It's hard to beat the left foot brake dyno for spot checking AFR's at various rpm's...need a good stretch of highway, get it up in 4th, left foot on brake and go WOT while keeping an eye on the wideband. Do a run at 4000, 5000 and 6000 (watch the radar detector also!). Here's one on my /4....turn up the volume!

https://www.youtube.com/watch?v=A4jyPRQaVNw

Posted by: Jetsetsurfshop Mar 6 2015, 10:23 AM

Ok Guys,
Here's my dyno results. I didn't have anytime to work with the carbs. The car was a little rich when we finally got some good pulls and it was a long day already so I didn't work on the fuel mixtures at all. My point of the dyno was for a TT classification with NASA. I hope this puts me in a class thats appropriate for my car.
I got to admit that if the car made more power I'd been embarrassed about my lap times at Sebring.



Attached thumbnail(s)

Posted by: ThePaintedMan Mar 6 2015, 12:04 PM

Very nice Shane. You should be proud of that, especially all the work you and Keith put into it.

I agree that the carbs are probably holding you back. What vents do you have in those 40s again? Are they 30mm? Eventually it would probably be prudent to get your hands on a set of 44s... or send your 40s to Racer Chris. He works magic on his that I simply can't do (mostly proprietary info that he developed over years and years of SCCA racing, but my guess is he reworks the vents and the carb throats so that they're at their very optimum.) And since he has a flow bench, he has verified that his 40s flow like 44s! I'd love to learn more about that someday.

The only other thing I would imagine that is holding you back is the heads, but you mentioned that before.

Still, very impressive dude. You should be proud.

Posted by: Racer Chris Mar 6 2015, 01:18 PM

Its a flowbench of the mind, not one with an existence on the physical plane.
I use the same tool when I do port work.

Posted by: ThePaintedMan Mar 6 2015, 01:58 PM

Now THATS why we pay you the big bucks Chris. I can do stuff on "theory" as well, but without the experience you have, I'm still mostly shooting in the dark.

Posted by: Mueller Mar 6 2015, 03:18 PM

Nice...must be a blast to drive!

Posted by: Racer Chris Mar 6 2015, 04:07 PM

primary venturis should be 36mm, but a stock 40IDF doesn't work all that well with venturis so big.
The carb inlet diameter is too small.
I can fix that.

Posted by: Jetsetsurfshop Mar 6 2015, 04:45 PM

I did the 34 venturis kit from CB. We did it a while back and the car does like it better. Called Chris to modify the carbs but I was spending so much on the car at that time. Needed to stop the bleeding. Not that it was to expensive, I didn't want to spend anything after the engine build. maybe one day we will get them done right.

Posted by: carr914 Mar 6 2015, 07:02 PM

On a Carb'd Motor, you really need a Carb Expert with a lot of different Jets to do a good Dyno Day.

Good Numbers though - what I expected!

Similar numbers that I had in this car.

Posted by: naro914 Mar 9 2015, 05:32 PM

We got Papa Smurf dyno'd the same week as you!
Not sure you want to see the chart though
Suffice it to say, I was very happy....

Posted by: Jetsetsurfshop Mar 9 2015, 06:09 PM

Lets see it!! Judging by that video i think your north of 250hp?

Posted by: naro914 Mar 9 2015, 06:17 PM

Just a bit...

Posted by: wndsrfr Mar 9 2015, 07:06 PM

Sweet thing is the torque hangs in there 'way up to 7500+, really nice, and what a fine AFR trace--nice tuning!

Posted by: naro914 Mar 9 2015, 07:11 PM

Yeah, I was very happy. Ed Senf - who is the race engineer for Rum Bum Racing, engine development manager for Kinetics and engineer for a couple other pro teams - did the tuning. For better or worse, he knows our engine very well...too well if you ask me. Notice that we've run 44 runs with him the past couple years...

He got it up to 316 hp and 256 tq, but it was too lean. I don't need to be burning up engines...

Posted by: ThePaintedMan Mar 9 2015, 09:14 PM

Whatever. That's a six and on a VERY different budget. And, Shane built his himself. Apple's to oranges. Nice job again Shane.

Posted by: naro914 Mar 10 2015, 06:06 AM

Oh I agree, apples to oranges. Shane's engine is a VERY sweet 4!! HE asked to see it, I wasn't going to post it.

Posted by: stownsen914 Mar 10 2015, 11:08 AM

Nice looking chart, Bob ...

Is that at the wheels?

Posted by: naro914 Mar 10 2015, 11:23 AM

Yes, at the wheels.
I meant to take pictures and/or video of the dyno runs, but completely forgot.

Posted by: stownsen914 Mar 10 2015, 02:18 PM

Wow, nice