9sectruck

iTrader: (9)

Im game just let me know a few days head to plan.
Might be able to get a group to go.

Rise of the Phoenix

iTrader: (27)

Sounds good. I'll let you know.

If Devon was driving my car, what kind of ET do you think he could throw down?

KCS

iTrader: (20)

This should be a troubleshooting process right now. Those numbers are extremely weak. The last thing that needs to be done is to change a bunch of stuff at once. If a dyno tuning doesn't make better power and track results don't suggest better power, then something really is wrong and will need to be diagnosed as it may even degrade the health of the engine.

fly boy_1

iTrader: (4)

The main reason I say not to throw a bunch of money into na parts is that stuff would all be for nothing when he goes turbo (saw some of his posts in the fi forum). If you plan to stay na for a long time then yeah its worth it but imo all that extra money to get to 460-480 at the wheels is a waste when you are shooting for 550+ with boost. If it was me id have the tune checked on the dyno for anything left and just enjoy it as is, he said he was happy and it pulls hard so whats the justification imo.

9sectruck

iTrader: (9)

5000/5500rpm launch . I would guess 11.30s
just a guess

JakeFusion

iTrader: (7)

I don't think they are that far off. If it was 380, then yes. But to be honest, the AI heads are not putting down numbers here lately. Maybe the combo is wrong. But there have been a rash of low dyno numbers on this site. Maybe that's what happens when shops don't install their cams and heads and tune them. But these are legit numbers.

I'm not being a dick. The car is down on power, but it's not far off. If the headers are worth 15-20 and the tune is off by 5-10. He's right where he should be. Not a lot of troubleshooting to go through. And that's why I'm not advocating a big change. The UDP and ported TB won't do much to the tune and are relatively inexpensive items that help a little with the numbers. A change in headers might throw the A/F off a bit. The troubleshooting is probably in the original tune. If it still can't get above 420, look at the valvetrain setup. Tho the graph looks clean there with no obvious issues.

And at this point, only make changes you can keep if you go FI. UDP is a waste. TB is not. Better headers are not if you're doing a supercharger.

fly boy_1

iTrader: (4)

I doubt headers will make much difference in the tune. I went from 1 3/4 hooker headers to tsp 1 7/8 headers and gained almost 20whp and the tune was still just fine.

It just seems foolish to throw all this money at something that might not even be a problem. IMO the smart thing would be to hit the track and see what kind of moh it puts down or run with some known fast local cars and see how it stacks up. If its slow then dyno tune imo.

KCS

iTrader: (20)

So he troubleshoots the tune on the dyno and has his baseline. Then adds the pulley/throttle body/TSP 1-7/8" headers, tuner barely has to do any tweaking or he even skips the retune altogether, and he can report verifiable gains from the new mods with evidence. TSP is so happy to see a back to back comparison to show gains with their headers, he gets 10% off a FAST intake lol.

JakeFusion

iTrader: (7)

lol

Or, as pointed out above, Kooks headers are on sale. I'd do that. But I'm not biased or anything...

KCS

iTrader: (20)

Sales@Tick

iTrader: (3)

I was going to say the same thing.

If you're chasing a dyno number, and I know you're not chasing one you just want to see it perform up to your expectations, but you owe it to yourself and your wallet to try another dyno first.

If it doesn't perform like you expected, then start throwing more money at it.

Rise of the Phoenix

iTrader: (27)

For $100, I can have the dyno rented for an hour and I'll have my tuner (9sectruck) work on the tune. The numbers can only go up in my opinion. Kent (9sectruck) knows what he's doing, but like I've said all along, the tune that's in the car now was strictly done with him doing street tuning. With him being able to really hone in on the tune witht the car being on the rollers, I think there is another 15 or more rwhp to be had. I know the headers aren't optimal and neither is the intake, but they will likely remain on the car for a while. I'll pull the TB off this weekend and port it myself. I should have done that before now, but it is what it is.

I understand that dyno's are different across the board, even if they are the same brand dyno. I just know that the one guy on here (can't remember his username) has the same cam and ported PRC 5.3 heads, the same 1 3/4 headers, stock LS6 intake, pretty much the same damn setup I have, and he's making right at 430 rwhp. I know Martin said that my AI heads would be worth 10 to 15 rwhp over those heads, so I'm just trying to get justification out of all the money I spent on them.

JakeFusion

iTrader: (7)

I'm not starting a rumor; just making an observation. I also stated that when the heads, cam, and tune aren't all done at one shop, this is usually what you get. And I stand by that assessment. Read into it as much as you like. It's a sentiment that has existed for a very long time on this site and shared by a great number of people and isn't directed at any one shop in particular, although you are clearly blaming the camshaft designer here.

But what I'm clearly saying is the combo is restricted by those 2.5" collectors in ways everyone seems to be ignoring. Swapping out 1-3/4" headers with 2.5" collectors for those with 3" were worth 20rwhp on Vettes back in the day. He wants 440. He can get to 430 cleaning up the tune and swapping out the headers. I very much doubt he will get to 440 without a swap in headers. And if he's chasing a number, he might as well stop now and just enjoy the car. If he can find a good deal on headers, sell off his current headers, and essentially break even, then that's a no-brainer as well.

But that doesn't mean the combination isn't performing; it just isn't performing in the inflated internet forum world. He's still ~115rwhp over stock with a 227 cam and ported heads with poorly designed headers and a stock LS6 intake. And he doesn't have an UDP or any sort of help to the intake tract.

I just don't see this as some big conspiracy as to why the combo isn't making power. Yes, the AI heads aren't producing statospheric numbers, but the combos aren't optimized either. It's making exactly what you'd expect without a cleanup tune and collectors that can't effectively evacuate the exhaust gas. Per David Vizard, exhaust collectors contribute as much or more to a headers power potential than the primaries.

With that, I'll bow out of this. I've made my point.

KCS

iTrader: (20)

To me, it's the low torque output that tells me something isn't right. Yeah the horsepower sucks, and to be honest, for the money I would be upset even with 450whp, but I think the torque should be much better. Hopefully, Kent can get it sorted out and you can pick up some respectable numbers. Then hit the track before its too late and see what your MPH looks like. After all that money on those heads, I'd want something to brag about!

Sales@Tick

iTrader: (3)

Seeing how much time and money LG has put into merge collector design, I'd say that statement carries a good amount of water.

Rise of the Phoenix

iTrader: (27)

Money is something I don't have a lot of right now. So, for the time being, I'll port the TB, setup a time to rent the dyno for an hour and work on the tuning. From there, I'll see what kind of improvement I get and go from there. If it would have put down 415 rwhp and 400 or more rwtq, I would be more OK. That torque number just seems way low to me, especially seeing higher torque numbers out of this cam with stock heads.

JakeFusion

iTrader: (7)

Well, I can never leave well enough alone.

The five variables in exhaust tuning are:

1) Primary length
2) Primary diameter
3) Collector length
4) Collector diameter
5) Exhaust valve size/port cc

In general, F-Bodies are limited in primary length, so the exhaust tuning comes from diameter and collector design and the exhaust port. This is why you see QTP HVMC making much better numbers than other 1-3/4" headers and why the ARH/Kooks 1-7/8" with HVMC are the creme of the crop.

I've stated this before, both from what I've observed, and what others who have shops have told me, but larger diameter exhaust valves and larger exhaust ports are more sensitive to the other variables since they generally do not have the velocity of a smaller exhaust port. AFR heads come to mind. These AI/Dart heads have huge, high flowing exhaust ports and should probably be treated like an AFR head, though they have smaller valves than AFR heads.

However, one thing AFR heads are is sensitive to wide splits and overlap. I think the torque number being low can be attributed to over-scavenging during the overlap cycle, pulling the incoming charge right through to the exhaust and making less than optimal torque. The collectors being less than ideal might actually help bring torque up since they help counteract this principle. But in general, they aren't doing an effective job of evacuating the spent charge during the exhaust cycle and that is perhaps causing reversion of the exhaust gas into the intake cycle, killing power and torque. Or, it could just be that it's a big jumbled mess during the overlap cycle where fresh air isn't coming in efficiently and spent charge is languishing in the cylinder.

Just my thoughts there.

Sales@Tick

iTrader: (3)

AFR 205's, 365 c.i., Fast 92, 242/250 108+3 through a 6 speed. 30 degrees of overlap made this:



Granted that cam was never destined for those heads or a Fast 92, it just happened that way. Customer sold the engine and the new owner put AFR 205's and a Fast 92 on it.

How did Dr. Whigham make 460/420 with AFR heads and 9 degrees of overlap, but 10 degrees of overlap and these RHS heads with a smaller valve are being over scavenged?

From what I've seen a larger exhaust port or valve makes higher peak torque than a smaller port and valve, but it makes less peak hp.

Rise of the Phoenix

iTrader: (27)

Martin, by looking at the dyno graph, what do you see. I know we talked about what type of numbers we thought it would put down and this is not what I was expecting.

Sales@Tick

iTrader: (3)

Take it to the track or another dyno.

Dynos are nothing but a machine. There are many known low reading dyno jets. Some are just "honest" some may have outdated weather software.

They are used for tuning. The track is used for measuring performance.

I didn't know the SW headers had 2.5" collectors and I agree that isn't helping. The car you're comparing your car to of Stroked383's has 3" collectors so it's not quite an apples to apples comparison. IMO if the two cars aren't on the same dyno, or haven't been on the same dyno, it's not a comparison that can be made.

I also told you when you bought those heads after you bought the cam from me that you would be the first customer I've ever had to run those heads. I remember pushing the Ai stock castings on you, but saying if it comes from Ai it's going to be good stuff. That's water under the bridge and we can't say it's the heads without testing another set of heads. Which you can't afford to do, and even if you could I probably wouldn't be so quick to do so.

Just giving you my thoughts as you asked.