A good day at the dyno...

[XfireZ51]

Originally Posted by LGAFF

That's with flowmaster exhaust and possibly a tune...

Maybe a cat back, but he was stock.

[Top Toy]

Originally Posted by Wide_One

Here ya go, this is a stock California smog car with no cat backs. The time slips are not my best but consistent.

Wow! 387 RWHP from a stock motor is really strong! When you say "no catbacks", do you mean the exhaust was stock or disconnected?

[Top Toy]

Originally Posted by XfireZ51

Pete and I were noodling this a bit, and based on typical trap speeds(~112mph) for stock LT5s for 375 hp motors, we figure motor is actually more like 400chp.
Typical chassis dyno results for stock 375hp motor have been ~ 330RWHP.
That's ~17-18% loss, so GM assumption appears to work out.
Makes you want to get your hands on those original dyno sheets.

There is a Mercruiser LT5 Dyno sheet on display at the NCM. I don't recall the exact HP but noted it's for a second gen motor and was under 400 CHP. Probably more variation from engine to engine than we would expect and why they don't want to release them.

Sent from my HTC U11 using ZR-1 Net Registry mobile app

[Wide_One]

Originally Posted by Top Toy

Wow! 387 RWHP from a stock motor is really strong! When you say "no catbacks", do you mean the exhaust was stock or disconnected?

To answer the question, I meant stock exhaust Sonoma and most tracks won’t let you let you race because of noise issues. I notice on your stock or mild mod dyno slip you are at 394 that is stout as well. Different than some other the “on dyno” rev limit yours is well into the 6k+ range why would people go lower. These are amazing engines and I don’t think my engine or any other are freaks just not exploited. I agree with people who say real power is proven by track results and I go for the low hanging on that. The most fun is running heads up with equal hp cars and seeing the difference in power ban. Track proven HP is king everything else is on the bench.

[Vette73]

Originally Posted by Wide_One

To answer the question, I meant stock exhaust Sonoma and most tracks won’t let you let you race because of noise issues. I notice on your stock or mild mod dyno slip you are at 394 that is stout as well. Different than some other the “on dyno” rev limit yours is well into the 6k+ range why would people go lower. These are amazing engines and I don’t think my engine or any other are freaks just not exploited. I agree with people who say real power is proven by track results and I go for the low hanging on that. The most fun is running heads up with equal hp cars and seeing the difference in power ban. Track proven HP is king everything else is on the bench.

I agree......Numbers are nice but each dyno from what I understand read differently......

From what I hear they are very good tuning agents if used properly...Power through the torque curve I'm guessing, is better than peak horsepower in the real world....

Isn't it true that mustang dynos read differently than a dyno jet?





Sent from my LG-TP260 using ZR-1 Net Registry mobile app

[tpepmeie]

Originally Posted by Top Toy

There is a Mercruiser LT5 Dyno sheet on display at the NCM. I don't recall the exact HP but noted it's for a second gen motor and was under 400 CHP. Probably more variation from engine to engine than we would expect and why they don't want to release them.

Sent from my HTC U11 using ZR-1 Net Registry mobile app

The one I have from the 93 production sign-off was 404.5hp in Test 4 trim. From memory, this is full production intake and exhaust hardware, MBT timing, and optimized fuel mixture. Equivalent to a good aftermarket calibration.

that's corrected to SAE 1349 conditions, steady state-non-accelerating.

a 500-rpm/sec acceleration test might knock that down 10 hp. So 395 SAE, for an acceleration test, engine dyno.

Chassis dyno data points I've seen for later MY LT-5s are in the 340-350 rwhp SAE corrected. A 45-55 hp "driveline loss". or 11-14% at stock power levels.

I've had a couple of these on both engine and chassis dyno, and observed closer to a fixed hp loss. But, that's just my experience and limited data points. I'll be putting another one on the engine dyno soon.

[XfireZ51]

Originally Posted by Vette73

I agree......Numbers are nice but each dyno from what I understand read differently......

From what I hear they are very good tuning agents if used properly...Power through the torque curve I'm guessing, is better than peak horsepower in the real world....

Isn't it true that mustang dynos read differently than a dyno jet?





Sent from my LG-TP260 using ZR-1 Net Registry mobile app

Two motors with the same “peak” power but the real difference is as Paul has said many times and its the area under the curve. Typically, our motors will lise powerbat a slower rate, once past peak, than an OHV or pushrod type motor.

[Top Toy]

Conventional wisdom over on the Vette forum says the Mustang dyno's register lower RWHP numbers than Dynojet by 8-12 %. Mustang dyno's use a brake to control acceleration and measure power whereas Dynojet uses an inertia drum and measures acceleration. Mustang claims their numbers are more accurate but the Dynojet numbers sure sound better!

Sent from my HTC U11 using ZR-1 Net Registry mobile app

[jss06c6]

Have done quite a bit of research in the past couple of months regarding Dynos. Partner and I have started Crossed Flags Performance and are building a new facility in Magnolia, Tx. More on that later, but we are strongly leaning toward Hub dynos like Mainline. These allow total control over the load presented to the engine, which allows us to map the full VE tables and quickly zero in on optimal fuel and spark for any setup. Only drawback is if we want to host Dyno days, as the setup in a hub Dyno is much more involved.

Sent from my QTAIR7 using ZR-1 Net Registry mobile app

[Wide_One]

I happen to like the mustang dyno pack because it’s cleaner and less of a contraption bolts right up as the tires would from there its numerical input just my thought.
Left Side Not Right----All mine were done on the Pack gotta watch lug bolt stretch though.