Hit the Dyno Jet Today!

[matjow]

92 degree ambiant temp in Tampa, Florida on 08/17/2006.

416 H.P. at the rear wheels.

4 Pulls.

Worst pull was 414 RWHP.

Best pull was 416 RWHP.

MJJ

[GASSR]

Hey Matt

Whose shop did you use?

[2005SSR6Speed]

With numbers like those, I cannt imagine his shop doing alot of dyno pulls for people (some shops set them up to read real low). Remember that a dyno can read just about anything that the operator wants it to. Do you have a printout from the dyno?

[matjow]

I had world famous Jeremy Fromoto of FasterProms tweak my tune a little bit. Seriously, people have actually flown this guy to Pennsylvania and Australia just to tune their cars. But, lucky for me, he lives in my home town.

I just used the dyno for more of a tuning diagnostic tool. I didn't even take a print-out.

The dyno was at Ford Speed (FordSpeed.com) at 118th Avenue and 66th Street in Pinellas Park, Florida. It's a Dyno-Jet.

My pre-tune run was 395 RWHP.

My final post-tune run was 416 RWHP.

So, 21 RWHP for a tune tweak is not too shabby.

We also took out the stock spark plugs and put in some Autolite 103's - as they are 2 gardes cooler than the OEM plugs and you can, therefore, get a little more spark advance out of them without any knocking.

MJJ

[1HOT12C]

You have an 05 right???


You should be upperwards of 450. Probably a bad setup on dyno, but now you have a baseline to judge any new upgrades if you use the same place.

[matjow]

It's an '05. Everybody tells me that. I was just happy to break the magic 400 rwhp mark. There is no disputing that anything on the road with 400+ rwhp is a muscle car.

[JimGnitecki]

Matjow: Are you 6speed or automatic?

The 416 number is not offbase from what I have seen. Yes, you'll find some dynos that read WAY higher, but if you read the history on how the Dynojet "factor" was developed by its inventer, you will either laugh or cry. As 2005SSR6speed ays, the setup from one dyno to the next varies a lot.

On my own slightly lean (due to larger throttle body) recent runs at Colvin Automotive here in Austin, the dyno was reading 410 to 415 rwhp, and the LS7 Z06 that dynoed right after me (30 minutes or less after) came in at 400 to 405. And he had the 6speed versus my automatic (an automatic burns up an extra 10% of the crank power as heat). A stock 04 SSR came in at around 227 rwhp on this dyno.

You are right to use it as a diagnostic and tuning tool.

By the way, the technically correct explanation on the sparkplug recommendation from your tuner is just slightly different than what he said. It is not that cooler plugs make more power on an otherwise properly tuned engine; it is that stock plugs are often too HOT for a supercharged engine, and if so, they cause preignition (because they run at too high an electrode temperature). So, a cooler plug is bnot a part that adds performance; it is rather a part that corrects a problem caused by too hot a plug. Your tuner was running into preignition, and therefore had to back off on timing or AFR or both to quench it, which cost you some power. B y installing plugs of the correct heat range for your engine, he eliminates the root problem, and then can cease "masking" it via too rich a mixture or too delayed a timing setting.

I mention this because we shouldn't give othe rowners the idea that a cooler plug is a cheap "hop up" part, as a cooler than required plug tends to make an engine run WORSE because it fouls up.

Jim G

[matjow]

I have an automatic in mine with a Yank 3000.

[JimGnitecki]

Matjow: I too have the Yank 3000, but modified by Greg Ducato and his crew at Phoenix Transmissions! I'm glad you mentioned it, as it is VERY significant.

Per the Kenne Bell people (who do a LOT of dyno testing!), an unlocked high stall converter displays at least 6% less power on a dyno test than when the test is done with the torque converter locked. That makes your (and mine) dyno readings automatically at least 6% understated.

But be careful. I would not recommend locking the torque converter (via software control) for a dyno test, as that puts loads onto the locking system that it was not really desgined to handle.

The lockup is intended to be used at CRUISE, where engine / driveline mechanical decoupling and torque multiplicaiton are not needed. To apply several hundred horsepower to a locked torque converter is doing somehting that the engineers did not design it for.

Just know that dyno testing with unlocked torque converters, and particularly high stall ones (inheently "looser" than low stall ones) understates what the engine is really producing.

Jim G

[matjow]

So, if I ran at 416 rwhp and added 6%, that would be 441 rwhp.

I have also heard that you can add 1% loss or gain for every 10 degrees in ambiant temperature.

My run was at 90 degrees. So, when it finally hits 70 degrees here in November I'll be looking at 450 rwhp.

Sounds good to me.

MJJ

[JimGnitecki]

matjow: The temperature changes are not that easy.

First, the dyno software reads the temperature, humidity, and barometric pressure from a special station. It uses SAE formulas to "normalize" the raw data gotten on the dyno run back to EITHER of two different temperatures, depending on if they are using the new (J1349) or old (J607) SAE standards!

But, as I explain in my e-book, those standards assume that any engine can "adapt" "ideally" to any specific local tempeature, which is plainly not true for "real" engines. Every Chevy engine I know runs a lot better at cooler ambient temperatures than at hotter ones, by MORE than the formulas predict. If your dyno testing was done at 90 degrees, yes, you will pick up power if re-tested at say 60 degrees, BUT the amount of gain is NOT predictable precisely because the formulas were already applied to INFLATE your raw poer numbers to reflect the 90 degree test anbient conditioons, but that "correction" was itself insufficient. Bottom line: you will need to re-test on the dyno at cooler temps and see what you get!

The reality is that dno numbers should NOT be used to compare engine performance, unless the tests are done back-to-back on the same dyno on the same day with stable weather conditioons AND using whatever protocol is agreed upon by all participants (on a sweep versus steadystate dyno test, the rate of drum acceleration makes a difference in power reported. This is why many dynos have "shootout" modes in which the rate of drum acceleration is precvisely controlled for just this reason.

Jim G

[Royalshowing]

I would say it is right on the mark. Having a 03 Cobra Mustang dyno at 342 to 348 rated at 385 HP and my friend's 03 Z06 dyno at 342 against my 348. Later going to Superchips twice in Sanford, Florida and coming away with 412 RWHP, when starting with a baseline of 342 RWHP. The factor that most are missing here, is how aggressive is the tune. A expert tuner does not take it to the limit of gernading.
Believe that lower 400's RWHP will kick a lot of ass