Swapped heads cam exhaust - how much power

[pima.1971]

OK. Just did a cam head intake and full

exhaust job. How much power do you estimate? I have nothing to compare it to so no way of knowing until I get it on a dyno. I thought I might be able to roast the tires from a slight roll, but to no avail. Maybe I was expecting too much. Does run good. Lot better pull through the entire rpm range. Its definately faster, but I can't tell if its 40 hp more or 100hp more. Here's the specs and I'm still tuning it and have a wideband too. So any tuning suggestions are welcome too.

94 k1500 ECSB 5.7 stock bottom end.
hedman lt headers
2 1/2" duals with x pipe and cherry bomb turbo style mufflers
212intake/218exhaust @.50 with 480/490 lift roller cam and matching valve springs
906 vortec heads machined for higher lift with a quench of .040-.045
victor jr 2 bbl intake
3" open element on stock tbi with 61lb injectors with ultimate tbi mods
13.5 lbs fuel pressure with a new tpi fuel pump

I was expecting to run out of fuel at high rpms, but the injector duty cycle never got over 50%. Makes me wonder if I'm not getting all the power? Or is it because the intake is a single plane and can draw from both injectors?

Thanks,

[PJG1173]

this is what I learned when it comes to this stuff. who cares what #'s it puts down as long as it puts a smile on your face. to get a vehicle that heavy to break the tires loose at a roll takes a good bit of power.

I would suspect that you will run out of air before fuel at the upper rpms although that is quite a mild cam.

how much more timing have you given it over the stock tune?

[pima.1971]

The main spark adv table has 36* in by 3200 rpm but watching my datalogs timing never goes over 30*. Spends most of the time between 25* - 30* except under wot.

WOT at 2500 I'm at 20* and creeps up to 24* at 4500rpm at wot. Knock retard has not gone into effect so far. A few knock counts though.

I do understand not caring about numbers. But after all the effort I do want as close to 100% of the potential as I can get. I'm not satisified if i feel I got 70% of the potential even though it runs better.

[PJG1173]

did you set the calc in the ADX for timing to match what the base timing is set for in the bin? that would account for the data logs not reflecting properly.
I found when I did my vortec head and cam swap I needed a considerable amount of timing. I ended up modifying a lt1 cop car timing table. I just polished of WOT on the dyno last week. Its a nice smooth curve up to 4700 rpm where Kpa starts to drop and the dyno showed serging up to 5800. with mine I zero'd out my PE timing and just use the open throttle SA table. at 2400 WOT I'm at 29* and 33* up to 6000.

I was quite disappointed with my dyno results considering how much I have put in this truck, but I'm happy with the performance of the truck.

[EagleMark]

Is it normal for these trucks to run about 14.5 volts at battery and about a volt lower at fuel pump?

Second concern is when you do go WOT your BPW went high and Injector Duty cycle did not? So I was watching voltage again and battery volts dropped to 12.5 volts, happened 3 times during WOT but fuel pump voltage stayed same around 13.5 volts. So maybe alternator is going bad or belt is slipping at WOT? Loose wire? Got to have consistent voltage for ECM/PCM to work right and injectors to flow right.

Your log shows very rich everywhere but WOT which is close...

Power Enrichment hardly ever came in, must still be set with big delay.

There's a Code 33 set. So have to clear that and see if there is an issue.

Looking at the log I'd guess it's a stock bin? Got to get VE tables set for the new cam and heads and have to work in a performance spark table if you want to see near the power the new parts will put out!

Spark advance has way to many variables added to and taken away from main spark table to say what your actual timing is! Also to get accurate reading in data acquisition file for spark advance you need to set it up with what your base timing is. What is your base timing? Distributor setting with wire disconnected... then that number needs to go in offset of conversion of spark advance in ADX file. Then check timing at timing marks to see if they match up to what ADX file says it's doing.

Time to Tune!

[jameslleary]

I am wondering if it is his intake manifold that is keeping his giddy-up in the higher RPM ranges.
If you have the manifold I am thinking of, with the large runners, your not going to do much under 1800 or so rpm, maybe even 2000. For intakes, I kinda think the same way as exhaust.....if the primaries are too big(diameter) you are going to loose flow velocity. Same with large intakes, especially when the fuel delivery device, carb or TB, that relies on the manifold surfaces to mix the air/fuel charge. The only way you would not have these issues with a single plain, is if you have the MPFI version, and use it as a dry manifold set up. I know that this is a long shot, but maybe see if you can find a vortec dual plain to try before you really start banging your head because the results are not what you expected.
I you cant find one, you will have to cange your gears to get the results you are after.
Just my $0.02 from experience.

[pima.1971]

My base timing is in the bin and distributor at 8*.
I modeled this swap after "fast305" reading his posts for a longtime. From the heads, similar cam, and exact intake manifold. He has touched base on a post in FSC. The expectation was that there was no way 61lb injectors at 13.5 psi could feed this thing for any meaningful performance above a certain throttle position. But that is not what happened. The injector duty cycle never got close to maxing out. The needed fuel pressure was expected to be closer to 20 psi for wot. So something is off, but not sure what.
Can my timing tables and VE tables be adjusted so performance will jump and thus require my injectors to push more fuel. I mean to go from a 50% duty cycle to 80%? It's not like my afr is really lean.
I have zero'd out the spark biases, coolant temp bias, egr bias, and pe spark. I did leave the maximun knock retard at 6* for safety.

[pima.1971]

did you set the calc in the ADX for timing to match what the base timing is set for in the bin? that would account for the data logs not reflecting properly.
I found when I did my vortec head and cam swap I needed a considerable amount of timing. I ended up modifying a lt1 cop car timing table. I just polished of WOT on the dyno last week. Its a nice smooth curve up to 4700 rpm where Kpa starts to drop and the dyno showed serging up to 5800. with mine I zero'd out my PE timing and just use the open throttle SA table. at 2400 WOT I'm at 29* and 33* up to 6000.

I was quite disappointed with my dyno results considering how much I have put in this truck, but I'm happy with the performance of the truck.

It always seems a dyno disappoints. We read everything and calculate Flywheel hp. Then do a dyno run and get RWHP. Even when you add back for drive train loss, its never the same. It always feels like your trying to inflate your numbers. Sounds stupid, but that's the way it makes me feel.

[PJG1173]

are you sure you have 61# injectors? I took the injectors out of a 91 z71 parts truck my buddy bought and found they were 68# cop car injectors. the PO never messed with them so they some how came factory like that.

[jameslleary]

Edit: do you have an AFPR?

[pima.1971]

Edit: do you have an AFPR?

Yes but i do need a different spring as this one is just about maxed out. But it is adjustable, but only goes lower right now.

[pima.1971]

are you sure you have 61# injectors? I took the injectors out of a 91 z71 parts truck my buddy bought and found they were 68# cop car injectors. the PO never messed with them so they some how came factory like that.

orange/orange insulated posts. Those are 61lb hr right?

Let me go double check.

Their orange and orange.

[jameslleary]

I think most injectors have those orange posts. you want to look for paint marks on the center injector post, where the connector locks on. yellow and brown paint marks would be the 65pph, Orange and black would be the stock 350 injectors, and green and white are for the 305. unless you get an external regulator, you will have to get the regulator, or at least the spring from a 94-95 454 TBI which ran 46pph injectors @30psi, which made them 74pph.

[EagleMark]

Paint marks are all but gone nowadays, the post color does not indicate anything.

Grab the number and look, there's lot's of differant information on how much they flow, we started a list and supposed to be correct for 13 PSI
http://www.gearhead-efi.com/Fuel-Inj...d-part-numbers

Orange Black 61pph
Yellow Brown 65pph

You have plenty of fuel right now and need to adjust lower VE down. But installing the timing table that went with the motor Fast355 built would be first for big improvements. With 8 degree distributor setting figured into the ADX file you are running about 12 degrees advance WOT. And cruise about 18 so yes it would be low on power.

Now you have to be very careful with spark advance! You disabled a lot, did not account for 8 degree base setting. Have you checked at timing marks with light to match what ADX is showing?

[PJG1173]

I looked at your log file and ran it through the $0D ADX I'm using then exported it to a database that sorts the data. on thing I noticed is that your wb is reading differntly than what your BLM's are reading. so I would assume that your pcm is correcting for problems with your VE table and the WB is confirming that its making the proper corrections. attached is a report I threw together showing diffent views of your data. to include duty cycle info.