69LT1Bird

iTrader: (1)

Well I finally got my car dynoed today and was not thrilled. I, like others expected more. But doesn't everyone. This car feels like it has more, the torque is lower that I thought and about 30-40 hp less than anticipated. Car specs are in sig.

390/367, I was told SAE was 406hp. Locked TC.

This was done on a Dynocom dyno. The AFR was logged on my laptop with HP Tuners. The 3rd pull commanded AFR was 12.96:1, actual 12.76 WOT, first pull 12.86:1, actual 12.62 , its hard to read in the file.

I have a dip/bog at about 5400 and then it takes off again, I can't see why, timing, fuel etc stays steady.

WKMCD

iTrader: (2)

I'm not familliar with that dyno but IMHO you're about 50 low on both sides in DJ numbers. Who spec'd that cam?

69LT1Bird

iTrader: (1)

Thanks for looking, I have followed your many builds. Maybe that dyno is low, the owner thought his personal car was way low and I saw a 454 bb with edelbrock h/c/i only do 303 rwhp two days ago.

Back about a year ago the cam was decided on by talking to a couple of sponsors and others, at the time there wasn't a lot of knowledge or options, there are obviously a lot more and better choices now. I am not sure the cam is the whole issue but maybe it is.

I have not had it to the strip but driving it the car pulls great and if you look at the MAF flow number, it is at 51 lb/min at 6451 rpms, 12.65:1 afr. Something doesn't add up. I know the tune is good. VE Sd tuned, then maf only tuned. AFRS are right on as are STFT/LTFT's. Kinda puzzled.

WKMCD

iTrader: (2)

Then amount of timing looks good. As you said, the early thinking of massive amounts of split has changed. People have had good results with as little as 2 degrees. I think I'd be looking at something with 6 to 10 degrees of split. The 234-240 112 +0 XE-R I ran in my build worked very well. I think on a 6 litre motor something like a 224-230 112 or 226-234 112 would work much better than what you're running now.

Just my $.02

White_Hawk

iTrader: (3)

Something isn't right. It goes flat at about 5700. If it kept rising, you would be up where you are supposed to be in the mid to upper 400's. It looks like valve float, but it is usually jagged instead of smooth. Maybe the dyno software smoothed it out?

You might not have enough spring. Also, are your knock sensors installed right? Spark knock could cause that too.

-Geoff

edcmat-l1

iTrader: (10)

Very good assessment. I'd tend to agree. But, it probably has good springs right?
What is your elevation?
Needs more timing.

69LT1Bird

iTrader: (1)

Thanks for the input guys. My elevation is only about 800 ft above sea level, SE Michigan isn't to exciting. How much more timing do you think Ed, I have had it at 29 with no knock but I didn't go higher on the dyno becasue of the flat spot. Figured I should fix that first.

I have the PAC 1218 springs (should have went with the 1518's) which I am push over the rating with the exhaust lift. Any spring suggestions?

69LT1Bird

iTrader: (1)

The valve float/spring idea is good but why would it wake back up and rev to 6400 with no further issues?

Haans249

iTrader: (24)

Harmonics.

Try hitting up another dyno for comparison, that will tell you if you have a real problem, or if the dyno is being funky.

Do you notice a power drop on the street? That cam could simply be running out of air being only a 222 intake duration. Like some have stated, i would like to see a 226-228 intake duration instead. I would also think a bump in compression to around 11.5 would help a bit.

Bad Blue WS6

iTrader: (41)

because im a tune idiot,,how much does it cost to do a dyno pull,, and now you have to / should do two? ouch.

69LT1Bird

iTrader: (1)

I get cheap dyno time so thats not the issue. I want the flat spot fixed first and then I may get a more aggressive camshaft, not sure. The flat spot is not dyno related it just shows up on the dyno. On the street I don't feel anything but I also don't run the same RPM/load etc as was seen on the dyno.

Around here a dyno run is $125 to do base run and $75 per hour for tuning after that.

snake charmer

iTrader: (118)

if you can maybe try a different dyno . you got a great setup and should be putting down big numbers . the only thing in the setup that i would change is the cam . it just looks like the cam is a little out there .

Hotrod406

iTrader: (6)

My setup is fairly similar and it made disappointing power as well. Combo is: 6.0 milled L92s 10.25:1 1.75 long tubes with 2.5 inch mandrel duals. Cam is a custom 226/238 .607/.610 lift 113+3 but I degreed it and it's 2* retarded. Intake is a sheetmetal, there are pics on LS1tech if you want to see it.

The dyno is a Mustang 250 and the guy said it reads a bit lower than a dynojet as usual. Numbers are SAE.

It's still a bit fat and I don't know the timing because my data port wasn't working. Max hp is 387 at 6800 and max torque is 343 at around 5300.

I don't know what the deal is when the LS3 Vette guys can make 500rwhp with just a cam and some bolt ons.

White_Hawk

iTrader: (3)

Get that thing leaned out! Did ZZP tune it? Those guys do mostly boosted Grand Prix's. It look s like a boosted AF chart too.

-Geoff

jason99frc

iTrader: (12)

If everything looks good with the air fuel, Get a G-tech or go to the track.
If it traps 118 - 120 and your car weighs ~ 3700 - 3800 with driver you are right on the 440ish range
If your less than 115 than something is wrong.
Probably tuning........
Ive run the G-tech in numerous cars from 105 mph 1/4 cars to 140+ trap speed cars and they are always accurate to track times + / - 1 mph

Good luck.

Hotrod406

iTrader: (6)

I should have stated that I have a wait4me tune that I leaned out a little at a time on the dyno. I was running out of time (and cash) so I called it good at 12.0. If I determine that the timing is out of whack I'll probably go back and do some more adjusting.

fastvet

iTrader: (2)

Thats a big split on your cam, and its a pretty small cam for a 6 liter. You need something in the 230ish range, and i wasnt impressed with the torque that was on that printout. That should of definately been high in torque at 3k thru 5500. maybe its the 16degree seperation, i dont know.

~my opinion is to get a bigger cam with not that much of a seperation and a lower LSA. Those L92 Heads flow too big of numbers for that small of a cam.

$.02

fastvet

iTrader: (2)

One more thing, I dynoed at 407 RWHP with a 224 cam 114LSA on a 5.7L engine with 5.3L stock heads milled to 59cc, which gave me a 10.9:1 compression. On 4.10's. you have better flowing heads, intake, and TB. ...its gotta be the cam bro!

Hotrod406

iTrader: (6)

That's what I'm thinking too. I hate being an early adopter on this stuff. I'll probably wait most of the winter before getting a new cam. Let other people do the testing.

69LT1Bird

iTrader: (1)

Hotrod406, I feel for your problem but I was hoping for feedback on my issue not yours. If you need more help on your car could you please start another thread.

Thanks.

Patriot Golds and one piece hardened pushrods will be here today. Hopefully that will help.