Dyno result

[Pod]

I finally found a dyno reasonably local to me (this is in England) and did a couple of power runs on their dyno.

It's got stock heads (thumper ported), stock cam and and stock intake (tmoss ported lower), 1.7rr, 65mm throttle body, headers and not much else, engine wise.

It turned out to be 309 hp and 365 ft/lb
They are flywheel numbers, so not huge, but I'm very pleased with that and really surprised!

The only down side is that as it has more power than I thought, it means I'm worse at driving it than I thought.
Best time is 14.06 @ 98 although it has done 101mph before with a slower time.

 

[FastDriver]

First, don't pay the dyno any mind... they're tuning tools and nothing more. SAE vs. STD, dynojet vs. mustang dynos, Engine dynos vs. chassis dynos, BHP vs. Gross vs. net.... The bottom line is that the hp number you see after a run can't be reliably compared with any other numbers you've heard on another dyno or when other correction factors are applied. Look at your trap speed vs. your weight. That shows you how much power you're really making.

Some things to consider: Elevation and track conditions could be the reason it's not performing as you expect. From a good track to a bad track you could see more than .5 seconds and 5 mph difference. On the same track the weather and how well it hooks on a given day can cause a 2-3 mph difference from one session to the next.

What were your 60' times? The good news is I think you're running close to where you should be based on your 98 mph trap speed on non drag-radial street tires. You're still probbaly in the 2.0 range in the 60' times. The 101mph run indicates better track conditions or a run where your car was cool and making the most power. Getting out of the hole quickly is a HUGE part of drag racing. With stickier tires, a tuned suspension, and numerically higher gears, you can cut time off of the 60' that converts to even more time shaved off of your 1/4 mile ET. Figure for every .1 seconds off of your 60', you'll pick up somewhere around .15 off of your ET.

You can try to squeeze a little more from your timing. Factory heads like somewhere around 14* timing on 93 octane gas. I'm not sure what you're running over in the UK. Also, I think your octane ratings are on a different scale than ours are. Our 93 is equivalent to something like 98 there, I think. Did you delete the air-silencer too? You can also ice down the intake prior to your runs to pick up an extra tenth or so.

Good luck man! Thanks for representing the ol' 5.0s in the UK.

 

[Pod]

What would be the best rpm to shift at, based on that graph?
(that is what I meant to ask in the first place)

60' times are around 2.0x on a good day. I've got MM lower control arms which have helped a lot. I want to get the rear axles stronger before I switch to drag radials.

Weight is the next part of the plan. Find somewhere to get it weighed and then see what I can do to reduce it, while still keeping it a daily driver.

 

[FastDriver]

I can actually do that calculation for you, but don't have the time right now. My instinct tells me that you should be winding it out to 5500 rpm or beyond for each shift.

That a/f ratio is crazy... goes from too lean to too rich. Ideally should stay around 13:1

 

[Pod]

I can actually do that calculation for you, but don't have the time right now. My instinct tells me that you should be winding it out to 5500 rpm or beyond for each shift.

Cool, thanks.
I have a shift light, but have been guessing what to set it to.

That a/f ratio is crazy... goes from too lean to too rich. Ideally should stay around 13:1

That is the other reason I went to the dyno. Any idea what could cause that or what I could do to change it? Seems like I need both more and less fuel, so changing the fuel pressure, for example, doesn't sound like it will work for both.

Thanks again - I really appreciate any help.

 

[Bullitt95]

It turned out to be 309 hp and 370 ft/lb
They are flywheel numbers, so not huge, but I'm very pleased with that and really surprised!

You should be really surprised! After all, unless the engine was out of the vehicle, how on earth could the dyno operator get accurate flywheel HP/TQ numbers?
It seems to me that they've run the vehicle on a chassis dyno (the Dyno Dynamics is a load type) to get rwhp/rwtq numbers and then used some mystery "correction factor" to derive flywheel numbers. That makes them totally meaningless. Some of the information IS useful though:

1. Peak HP is at 5100rpm and peak TQ is at 3700rpm. The general rule of thumb is to set the "redline" about 500rpm above peak HP so that's 5600rpm.

2. The shape of the HP and TQ curves. Your engine's making at least 90% of maximum torque from 2100-4800rpm.

3. The AF ratio is all over the shop.