I had my car dyno'd after my engine build and swap.
its a .40 over 350
Holley Stealth ram
LT4 hot cam with 1,6 rockers
EQ 180 lightning heads with 64 cc chambers
CR should be around 10:1

It only made 242/275 WHP. Granted this was on 21# injectors, but the car is about 100 HP lower than expected and I'm doubting that a tune and injectors can free up that much horsepower. Is there anything else I could be missing?

 

Remember a dyno is only a tool used to measure performance increases with proper tuning. Take the actual numbers for bragging with a grain of salt.

 

More details please.Decked or not??. Quench settings??. Cam straight up??. What pistons?? Leak down tested??. Compression tested??.

 

I agree for the most part, but when it comes to certain engine combinations that have been done time and time again, you expect a certain number.

Wish I knew where to start finding you lost numbers

 

That combo should make 300+ rwhp.I run similar combo,and I have fms 24 lbs injectors(48psi).Is your prom programmed to this engine?What exhaust?

 

I dont know much about those heads but they arent real big, only a mild step above stock. What valvesprings are used and was the cam degreed? Numbers seem low if its a dynojet.
Also was converter locked?

 

What brand dyno?
On a mustang dyno without locking the converter that's probably around 350 hp at the engine.
And TraviZ said it best. Take it with a grain of salt. The numbers don't mean anything compared to other cars. It's just a tuning tool. It's to show the tuner what the effect were for the changes he made.
If you want an idea of how much power you are making run it down the track.

 

How much did it pick up after the dyno tune? Or was it just run as is an no tuning done?

 

+1 this number means you make XXX horsepower and XXX torque on that dyno, you can't compare it to other dynos in other shops.

What is your timing set at? What transmission? Did you mess with the timing while you were at the dyno? I would tune your car on the dyno to get the most power possible without caring about the actual number. Another great place to go for real world performance is the drag strip, tune on your mph.

Finally, I am running a camshaft similar to the LT4 hot cam, and have read a lot of magazine articles/dynos/builds using it. 370-400 horsepower seems average for most of the builds. If you were hoping for 340 rwhp, that would be 425 fwhp. With 180cc heads and the LT4 cam, everything would probably have to be perfect. These magazine dynos are running no accessories, 1 7/8" headers, true dual exhaust and an E-water pump, oftentimes with a giant carb spacer and professional tuning, so the numbers are pretty hard to duplicate in a thirdgen.

 

Short block was brand new with flat top SpeedPro pistons from ATK. I'd imagine the block was decked and everything else should be good. Cam is straight up

Stock Prom. Hooker 1 5/8 headers 3 inch y-pipe and cat back

They're basically ported vortec heads. No idea about the springs because they came pre-assembled but they're supposed to be good for up to .600. Cam was not degreed and I'm assuming they ran the car in drive not over drive, which would mean the converter is unlocked. It was on a dynojet.

No tuning done

6 Degrees timing, 700r4.

 

How many degrees total timing and how do you know? You're going to want 36* total timing (my guess) and you're going to want to check it with a dial back light to verify.

 

tune it... report back...

 

When checked with a timing light it was at 6*. How would I check total timing?

 

http://forum.grumpysperformance.com/...hp?f=70&t=4683

http://forum.grumpysperformance.com/...hp?f=70&t=1015

 

No tuning done and you are disappointed? Did you honestly expect to slap parts together and it to magically be happy and work 100%?

Do some actual air fuel monitoring and adjust the timing via ecm tune. You likely have 50 hp waiting. Dont run the motor hard til you verify how its running, it could be harmful to engine life

 

Here is a zz4 cam and heads 9.5 comp , stock tpi and stock manifolds.
I tuned it for a few hours on the street and it was driven to a Dyno a few hours away made 20hp and 40 more tq , I just sent the customer two more tunes with 1.5% and 3% more fueling to see if it can make even more.

 

You need to either buy timing tape to go all the way around the balancer (so that you can use your non dial back timing light), or you need to buy a timing light that has a **** or adjustment on it that will allow you to see more than the 12-16* of advance that a stock timing mark shows you.

I don't pretend to know much about the EFI tuning portion, but the car is not going to be making peak power if your total timing is too low (or too high). That's a good, easy place to start.

 

Did you have a wideband attached for the dyno run?
How was your A/F ratios?
Where did you make your peak power?
Have you checked that your vacuum looks okay and you don't have a leak somewhere?

Last time I had mine on a dyno I only pulled 280+ RWHP on a 383 with 210cc heads, but I was going way way lean pulling A/F of 18:1 from a throttle shaft leak and I blew an intake gasket puking antifreeze all over that same run.

 

You don't do total timing with an efi car. Just base timing. Total is controlled by the timing map in the ecu. So there is no need for a dial back light or timing tape.
Your car is not making any power because you are running the stock ecu programing! I am actually surprised the shop that dynoed it didn't tell you.

 

Isn't the amount of timing provided by the ecu independent of the base timing, as the ecu has no way to know what the base timing is? Still seems to me like checking total timing would be worth doing :shrug:.

 

The ecu is programmed at the factory to assume base timing is whatever Chevrolet says base timing is, depending on the engine 0 or 6 degrees as far as I can recall. Besides that, it is worth checking total timing especially if you have a scanner to read what the ECU thinks the timing is at. Verification is nice and also lets you know you have no slack in your timing chain or distributor.

 

No. Its just a base setting for the ecu to calculate of off. The ecu does know what the base timing is as it is a diferent setting for every ecu. Usually 0 or 6 in Chevy. Ford and Chrysler are different also. Most aftermarket fuel injection systems you can set base timing to whatever you want in the software.
If the base timing for the ecu is 6 then when the ecu is commanding 36 it knows it has to add 30 degrees. If you set the base timing to 10 then when it is commanding 36 you will actually get 40.

 

Yeah, whatever the base timing is with the est disconnected, that value has to match the computer code or else the calculation will be off like above said.

Thats why if you take a stock L98 that has base of 6 and you change to 8, you added 2 deg to entire engine operating range including wot.

Some big cammed motors will not run on low base timing of 6, so you may need to set base to 10-12 deg or more. I shoot for minimum that allows motor to idle on its own without stalling. Then reburn chip with base changed to 10-12 or whatever value it ended up being so ecm knows what timing its giving to the motor

 

^ I agree.

Base timing is set and that's it with OEM EFI. You gotta take into account if it's knocking or something it'll pull timing back out so running too much initial timing will make it ping if proper octane isn't used and timing could end up less than normal.

 

GET IT TUNED!! Get the chip cut for your car. Its amazing how much difference it makes when the computer is setup right.......

 

Your bottom line should be with tuning going right back to the same dyno place.You should thank god you found place that is honest enough to give your real results.Alot of dyno operators would fudge numbers just to keep their customers happy.

Also it doesn't matter much what the dyno numbers mean.It's at the track and a combo that works together that really matters.