Blade

iTrader: (1)

The mods I have are in my sig.

When I dynoed it in November, it put down 310/322, with only an SLP lid and Cutout. (Dyno chart below)

http://img298.echo.cx/img298/8601/dyno11042ek.jpg

Since then, I installed Longtube headers, LS6 Intake, TSP catted Y, Magnaflow Catback and various free mods. !AIR, !EGR...etc...

It only put down 323/327. (Dyno Chart below)

http://img298.echo.cx/img298/7507/dyno67059eh.jpg

Obviously something is amiss. During all three runs, I get dips of 10-20HP/TQ loss, and the car doesn't seem to recover very well at all from them. I'm thinking that is the problem. As you can tell from the first dyno in November, it doesn't dip what so ever.

Also, ignore the 331 reading. I tried some dyno tricks like icing the intake and removing the filter to see if it would help with the problem, but it didn't do much of anything.
Please help.

triumphman

Sounds like it might be time for some programming.

Blade

iTrader: (1)

C'mon guys.

Any ideas?

glennster

iTrader: (1)

I don't think its that bad,when taking in that the dyno and weather were different.AIR! and !EGR won't help HP. I also think the LS6 is a no-gainer on close to stock.Stab a converter in and hit the track.People laugh at hand helds,I didn't laugh with my before and after dynos with the vinci.

baldurann

iTrader: (15)

A tune is in order.

Slart

It seems to me your tune is fine, you're right at 13:1 on all the runs except the one you told us to ignore. That leaves the timing up for grabs, but since your fuel curve is good I'll assume you put some time into it.

Keep in mind that putting high RPM parts on there only moves the torque curve around. That's all you can really do with an NA motor - if the combo was already well done you're not going to see substantial torque gains from better flowing parts, they're only going to raise the RPM at which you make torque. Moving the torque curve to a higher RPM is what causes more horsepower because horsepower is proportional to torque*rpm.

Due to the particular shape of your powerband, this isnt showing up as more peak horsepower. It is showing up as more average horsepowr (the additional horsepower is spead out quite evenly). Previously were making over 300rwhp from 5000-5900. Now you're making over 300rwhp from 4800-6250 (probably further if you raised the shift point).

Other than the launch, your engine will spend all it's time in the 4500-6200 range (because you shift out of one gear at 6200 and end up in the next at 4500). You only need power in this range.

If you were to calculate average power from 4800-6200 for these two combos, you'd see you made about a 10-15hp average gain.

I dont think you have a problem, these parts are doing what they should, they just dont happen to put up impressive peak figures. If you want impressive peak figures, you should get a cam that helps the engine breathe at 6500RPM. A 250@.050 cam would put up some awesome peak numbers, but it would not have a very wide powerband.

If you want to make the car go with these parts, the best thing to do would be to raise the rev limiter to 6800 and shift it up there. Better yet, if you were to raise the rev limit to 6800 and do another pull, we could decide at what RPM you want to shift in each gear (i can help with this - just msg me).

The reason you want to raise your shift point is you have a lot of unused power up there. Right now after you shift you are moving from 310rwhp (@6200) to 240rwhp (@4500). If you raise the shift point to 6800, you'll be making around 300rwhp@6800, and you'll come into the next gear at 5000 also making 300rwhp. As you can see, 300rwhp before shift/300rwhp after shift is better than 310rwhp before shift/240rwhp after shift.

You wont make more peak power by raising the shift point, but you will make more average power, which will also serve the purpose.

As far as the 10-20hp dips on the dyno, I dont know what that's about, is it possible you have a misfire? Based on the rest of the curve it does appear to recover in my opinion.

Good luck,

Steve

Blade

iTrader: (1)

The car still has the OEM tune.


I believe KR is responsible for the dips in power and the PCM pulling the timing. Without it, i'd probably be averaging 10-15 more HP throughout the powerband you mentioned. Which would give me around around a 25-30HP average gain instead of a 10-15 gain thoughout the same powerband.

Another weird thing is that I never messed with my shift points. It used to always shift at around 5800RPM until I put the headers in. Now it goes until it's about to hit the rev limiter before it shifts. (6200RPM)

I'm going to clean the MAF, seafoam it, and change the fuel filter. After that i'll dyno it on a more favorable day.

Race-Prep

The tune is going to be a big help with your car. Every car we get into the shop here has picked up 10-15WHP from the tune alone, I would look into the tune as there is much more to it than AFR. If you think your tune is fine by just looking at the AFR you need to get a scan tool and look at all the parameters in there and think about all the things you just changed from the stock setup then tell me you don't need a tune! If there is not anyone in your area that can do a good job for you make a trip down to our area and we can take care of it for you.

-Bryan

lilbuddy1587

iTrader: (1)

1. about your 250 cam argument, BS! Plenty of people run big cams like that, they just have to utilize that cams rpm range, I.E. smaller gears(4.10, 4.30, 4.56) to keep the car in the power band, such as what you stated with him raising his rev-limiter to allow him to drop into his power band through each shift

2. The stock cam starts to literally DIE @ 5600 or so rpms and you want him to raise his shift points to 6800 on a OE cam ? wow........... thats all I have to say, especially on stock springs..... HELLO VALVE FLOAT

3. To the original poster, it looks as if you need a tune my friend, that kind of a drop could be KR, false KR, and or just gm's f-ed up tables that allow the car to run O.K.A.Y anywhere.. Get a tune man, its worth it!

Slart

> I would look into the tune as there is much more to it than AFR. If you think your tune is fine by just looking at the AFR

Regarding horsepower, there is AFR and there is timing, and that's it. So what do you mean "there's much more to it?"

> you need to get a scan tool and look at all the parameters in there and think about all the things you just changed from the stock setup then tell me you don't need a tune!

Sounds to me like you're trying to sell something.

oh wait... you are.


BTW misread my post. I didnt say shouldn't get a tune, I assumed since his AFR was a flat 13.0:1 from 4000 up that he had a good tune. When you made your post, you had the benefit of additional information that wasnt available to me when I made mine. So please keep that in mind in the future before talking smack.

I agree, he could use a tune, but most of his benefit is going to be from raising the shift point to match his new powerband. You could gain some horsepower from timing (fixing the KR if there is some), but he'll gain 20hp average power from moving the shift points.

For the record, I am an excellent tuner. My final product is far better than anybody who's doing it for money, because as a businesss you cant afford to put the time into it to get it right (and it takes time - several days of iterative analysis to get maf curves right - before you can even begin a meaningful wot tune).

Slart

> about your 250 cam argument, BS!

All I said was that with his existing parts, if he wants peak power but doesnt care about average power, a 250@.050 cam would give him exactly that.

Why do you think that's BS?

You are inferring that I said a 250@.050 cam doesn't work. I didn't. Have you run a cam that big? I have, before there were LS1s (hell - before there were LT1s for that matter).

They work fine. They're an awful high compromise way to get power, but to each his own.

> 2. The stock cam starts to literally DIE @ 5600 or so rpms and you want him to raise his shift points to 6800 on a OE cam ?

There's more to air flow than the cam. I could go into depth but I dont need to - The bottom line is his dyno sheet shows that his VE supports moving the powerband up. If you cant see that from the dyno sheet then you shouldn't be making recommendations.

I can see these things from dyno sheets. That's why I can make impune recommendations.

lilbuddy1587

iTrader: (1)

I dont care what u see, there is more to the equation, but guess what ? He's gonna have serious valve float and LOSE power

I dont care if u have ran a 250+ cam b4, not all motors are the same(i.e sbc, lt1,lt4,lt5, ls1,ls2 etc.) all react differently to different cam(s) because like u said, theres more to it than just the cam

Blade

iTrader: (1)

I dunno about raising the limiter.....valve float would certainly be an issue then...

Slart

With a stock cam & valvetrain, you can get quite a bit out of the valve springs. The reason people think stock valvesprings float easy is they try them with aftermarket cams that have aggressive ramp rates. The stock cam has soft ramp rates for longevity reasons, and this requires less spring.

My A4 '02 shifts at 6425 (stock valvetrain). I've brought it as high as 6600 with no signs of valve float. I've never gone any higher because I determined there was no benefit going higher than 6425 with my combo, but my point is I know the stock valvetrain works to 6600.

The reason nobody else realizes this is nobody else has tried using a stock cam to 6600 because they didnt see the benefit. There are certain cases where there's a benefit (yours is a prime example). A lot of people on the internet focus too much on dyno numbers and not enough on the powerband. A bit short sighted.

Slart

slight correction. I know the stock valvetrain in an '02 works fine to 6600. Dont the '00s use a different cam?

Blade

iTrader: (1)

Yeah. It's a bit bigger with more lift and higher LSA.