Nickn20

If anything my dyno is conservative compared to others. My weather station is right by the car where it should be!

Bludevil415

Yes you are correct.This is the same dyno i have been using from day one.

Cold Zero

iTrader: (1)

I was following this thread post by post and page by page ! and what I can say :-

1. Great result for you Blue Devil

2. Tony Mamo you are the man, I'm really surprised how the bigger cam ( Actually we cannot say big cam ) didn't hurt the low and mid range power ! and it all about the combo and the magic in AFR Heads .. Tony you should have a call on Monday discussing my new engine valverain and ported FAST

Bludevil415

Something that i forgot to add is that the car made 511/437 Uncorrected, That is actual # before the SAE Correction.

1989GTA

You need to light a fire on that clutch repair. A lot of people are waiting for the final results.

litle88

iTrader: (20)

^^^what he said

JDMC5

iTrader: (3)

damn, I remember when 400 at the wheels was the number to shoot for.

Kaltech Tuning

iTrader: (17)

It's not about being a naysayer, I'm just asking why the opinion of this dyno has changed. Clearly there were some issues with the heads but before that was ever confirmed fingers were being pointed at the dyno.

Now that the heads have been fixed, the magical pixie dust was sprinkled on them, and all the other changes were made people are all giddy that this is a few steps from being a "legit 500 rwhp" car.

I'm simply asking questions based on the information posted in this thread.

If I wanted to be a naysayer I'd ask why, by mamo's own admission, are AFR heads only worth ~20hp over stock 243's??

I mean you can put $1000 or less worth of porting into 243's and pick up 20hp. Just look at the quote above where he says the dyno is 20 hp high, he also says with ported 243's he'd expect the additional 20hp. This is right from the horses mouth. Additionally the heads picked up 11 hp when they were bad, so if we're saying now the heads are only good for ~20hp that means fixing them was only worth ~9hp???

The bottom line here is that the OP is making changes to his car and seeing positive results, so that's what matters. However when reading through this thread these are questions that I came up with. I may have missed some info and if I did please point it out, that would answer my questions.

Tony Mamo @ AFR

iTrader: (13)

I guess I will address this first....

I think my comment regarding the original dyno and numbers produced with the 243 castings was accurate.....in fact Im sure most tuners and dyno operators would agree and some did much earlier in this thread.

Also, most of us also agreed the cam chosen for the original testing was far more optimized for the weaker exhaust flow of the stock heads and as such produced a good peak number while handicapping some of the AFR results due to excessive exhaust scavenging purging the cylinder of some precious oxygen and unburnt fuel that could have been converted into energy to drive the crank.

Also, Rudy did have the benefit of the cut-outs, a lightweight clutch, and barring the EWP and the porting of the FAST had most of his bases covered. The long and short of it appears this car just dyno's on the high side of average IMO....take ten cars that look the same on paper and I would wager most wouldn't have cleared 440 with the stock heads but thats just my opinion based on alot of other data and results I have seen in the past.

But truthfully its not worth getting hung up on because all the data we have seen has been and will continue to be on the same dyno.


How many times was "naysayer" brought up.....this kinda reminds me of the threads that start out with unhappy customers saying "I dont mean to bash"......and then we all know what ensues after that

OK....I don't have a problem with questions because I'm always straightforward in all my responses....and truthfully some of the points Kaltech brings up are good and perhaps should be addressed. My quick take on ALL of this lays out as follows

Had the original swap been new fresh heads from AFR the lower lift flow figures would have been a little stronger and they would have performed a little better in the first test but the reality was if you look back in the thread I clearly stated I was surprised the peak flow of the heads I received from Rudy (prior to reworking them) was very close to AFR's published figures so they weren't "that bad" originally and the overall results (450+ with an un-optimized combo) reflected that. I think the cam really hurt them and the choice of header (bigger 1.875 tube) compounded the cam's error but my guess is a perfect new set of AFR's in the same scenario may have only been 5-7 HP better (with the wrong cam/header combination).

Fact of the matter is even unported, factory 243 castings work pretty well and on the dyno usually make 25-30 HP less than the AFR 205 (with similar combinations designed to optimize both) but the power curve from the 205 is much fatter and broader than the stock curve and the part throttle and low RPM gains feel like you picked up twice what the dyno shows you. Also note that a stock AFR 205 is worth about 40 more horsepower over a standard LS (non 243 casting)....and once again shine even brighter if you take the time to look at the entire power curve improvements so looking or focusing on peak numbers doesn't quite tell the entire story. Also, most of the sharper guys know that a well sorted out combo with stock 243's can produce decent dyno and track results and if you've spent enough time on Tech you have likely ran into a few examples of that, BUT....if your looking for the really big numbers (and also value area under the curve) you need to be in a clean sheet aftermarket more efficient design (pick your favorite three letters....LOL)

Hypothetically if we see 490-495 when the smoke clear (the increase only from the reworked heads, slightly less compression, and larger more optimized cam), I think Rudy saw textbook gains from all the changes we made and thats good.

My ported 205's.....usually worth about 15 over stock heads (with a notable fattening of the curve which we saw here).....add another 4-7 here in this particular test to account for the fact the original state of these heads were softer in the lower lift region of the flowcurve effecting cylinder fill (and evacuation) in a negative fashion obviously.

The larger cam....Im going to call that 12-15 peak with another 5 tacked on due to it being more optimal for the new heads. But surely anyone who has installed a larger cam in the same combo knows....bye-bye lower and midrange RPM power and torque and the gains don't usually show themselves till your getting close to peak power and of course carry stronger past peak.

Not so in this case and if you want to call it the magic pixie dust that's OK but its simply the type of curve that a really efficient head with a conservative runner volume and alot of airspeed can produce....and it feels even better than it looks on paper to your right foot I assure you. Rudy gets it now and so do alot of others that have done a similar swap. The delivery of the power has a very different feel....old school guys felt the same when bolting on ported oval port OEM BBC heads 25 years ago (replacing their OEM rectangular ports) when there wasn't much in the aftermarket yet that you could choose from.

And yes....I agree a properly ported stock head could make similar peak numbers (due to the peak airflow of both heads being the same), but now you have an inefficient port simply larger and still inefficient. The peak number is there with a 230+ cc port but the area under the curve wont be nor will it feel remotely the same in the car (a much lazier throttle with poor tip in and roll on in the higher gears). And it wont run the same either because the curve with the highest average power will will and a fatter curve (with similar peak numbers) will always have more average power.

So whats funny is it looks to me that we agree on more things than we disagree on but our perspective on the final results (all the results perhaps) may have been skewed just a bit.

Sorry for the long post guys....I need to get back to my Sunday's activities

Rudy....get that clutch fixed and lets get back on the dyno!



Cheers,
Tony

1989GTA

Good answer Tony.

Bludevil415

Quick update for everyone. Turns out couple of the bolts backed out the flywheel some how causing the problems with the clutch. Car is back up and running and i will be going back to the dyno this saturday at 11am. So if anyone in the Bay Area wants to come check it out i will be at Newtech in Hayward. Also a special guest will be there Please no autographs lol.

1989GTA

Nice that it was a relatively easy fix. Looking forward to the dyno results.

Red99TA

iTrader: (11)

Good thing it's just some loose bolts but there's nothing easy about getting to those bolts on a vette!

litle88

iTrader: (20)

Still Subscribed and awaiting results, goodluck brotha.

1989GTA

Just checking in and waiting for the results this afternoon.

litle88

iTrader: (20)

+1^^^what he said!

djsanchez2

iTrader: (14)

+2 bump for results

Tony Mamo @ AFR

iTrader: (13)

Guys,

Im sure Rudy is busy or he would have posted already.

Long story short is I did have an opportunity to make it out there and meet Rudy face to face....as well as Nick and the gang @ NewTech, and while I would like to report better results for all of you, unfortunately this car seems to have a restrictor plate attached to it....LOL

We did improve the torque a little with a handful of 412 runs but no matter what we did, the power wouldn't budge off the 484 mark. Went from 24' - 28' of timing.....leaned the fuel to 12.8 - 13.0 around peak power (I would have pushed it a little leaner if it were my own car but the engine just wasn't responsive to change and I could tell Nick just prefers slight fatter A/F ratios). This engine was simply very unresponsive to changes....it didn't even dislike anything we did

I will say this, the car sounds great....is extremely responsive....idles smoother than I might have imagined and the curve is flat and strong. In fact the tuning changes did improve the shape of the curve upstairs with it maintaining peak power from 6400 to almost 7K before barely rolling over.

My take on todays turn of events is the intake/TB set-up is holding it back some. An unported 92 and an unported LS2 TB is only going to let so much air get to the cylinder heads. Also, Nick commented that the manifold KPA numbers kept dropping showing a restriction building in the intake tract as we turned the engine past peak torque (around 5K) and he also mentioned the Vararam CAI Rudy had on his Vette do not typically fare well on the dyno (but work better on the road and track though).

I think a ported 102/102 set-up on this combination would really wake it up....not to mention be a ton more responsive, especially compared to the stock LS2 TB which has a huge deadspot in the throttle the first 20% or so.

Rudy is hoping to get to the track in a few weeks....hopefully we see how the new combination effects his track times shortly which should be very interesting as well.

Its not all glory when your doing real R&D and testing like this thread has essentially shared....I would have lost a healthy wager today driving to the dyno that we would see 490 or better by the end of the day. The key is to try and learn from what transpired so you perhaps have a better day next time.

The car is healthy....sounds and runs great....but it is being held back and my guess after spending some time with Rudy today is given enough time he will likely look to push this combo a little further.

Im sure he may have a bit more to add and hopefully post a graph of one of the runs we made today.



Cheers,
Tony

bozzhawg

Another key aspect that has not been discussed is going from a .596 to a .624lift which generally shows a 5-10 tq gain and a shift upward in the torque curve. then combine an increase in duration.

20-30hp gain is what was expected.

I think you have a good ride and just enjoy it, don't be so hard on yourself. Your still prob faster than 90% of anything on the street and being hard on yourself is only going to cost you more money. I say this sincerely not pessimisticly.

Go out and enjoy it bro.......leave the dyno alone for a while.....


Bozz

1989GTA

"Nick commented that the manifold KPA numbers kept dropping"

IMHO that backs up Tony's thoughts on the intake restriction somewhere. Also the flat power curve from 6400 to 7000. I agree with the above post that no matter what that is a lot of power and you have a very good ride. Enjoy your car.