74u

iTrader: (9)

The clutch doesn't slip at all so I assume you are talking about weight. What do you think a lighter clutch/flywheel would gain me?

Keep in mind the new clutch has to be able to put up with constant traffic jam driving and not chatter my coffee/beer all over the console

Tony @ Mamo Motorsports

3750 lbs.....121.6 trap

Requires about 565 at the flywheel.....technically less (closer to low 500's) but I have successfully used this formula albeit in a conservative fashion for two decades and its usually very close to real world because very few street/strip cars are truly optimized to attack the quarter mile. A really sorted out car would need less power to achieve that trap speed assuming we are talking about reasonably good air quality and not racing in Denver. Lets say 800 - 1500 feet of elevation.....not great air...but certainly not mine shaft air seen in the Northeast in the cooler months. And of course when discussing track times knowing the DA is very important (the dyno corrects for it.....the track does not).

IMO 565 HP is pretty soft for a 416 (only 1.35 HP per cube), but not so much so considering a stock set of LS3's.

The real question is assuming the same displacement why didn't the cathedrals do alot better. Hell in 2004, my 346 with stock AFR 205's and a 224 cam made 550 at the crank and trapped 124 MPH in a 3450 lb ride (raceweight for my C5). That was FAST intake and all the typical bolt ons but a 416 with decent aftermarket heads (cathedral) and the right cam should be almost falling on 600 crank HP. I've made 650 - 665 at the flywheel with Mamofied 230's on a couple of 416 builds (granted these were optimized combos). But if you want to slice off 30-40 HP for the nickel and dime power additions its still up alot over what we are discussing here.

I quickly breezed thru this thread originally thinking this was a stock displacement deal. IMO what sticks out the most is why the TFS headed combo didn't make better power with the added displacement. I think a 416 with OEM LS3's is close to what one might expect but the TFS version with all that displacement was way off the mark.

I'm glad for the OP's sake it ran better with the recent swap but IMO this is a poor comparison of a cathedral versus LS3 style head debate. This combo should have easily been low 500's to the ground with the TFS heads. My 650+ versions of the 416's made well over 550 to the ground as you would expect (the highest one making 575 RWHP thru an M6 which made 667 HP at the crank.....which makes sense).

This makes for a great debate but the cathedral crowd got jipped with the original results....LOL

(Over a decade on this board....been dying to use that icon!!)

-Tony

speedtigger

iTrader: (16)

Not only did the square port heads make more power and go faster, but they did it with 12.5 degrees less overlap!

HISS

iTrader: (52)

Shhhhhhh square ports can't possibly.

74u

iTrader: (9)

Tony - not sure if you read my other dyno thread discussing the TFS combo, but it's about 12 pages (over the course of a year) of everybody trying to figure out why it didn't make more power. Most participating in this thread have been around since the beginning and know the previous combo was a failure for whatever reason (especially from a cost vs. results standpoint).

After exhausting all diagnosis (at least all I was capable of), swapping parts, picking the brain of most any vendor who would talk to me, and multiple fruitless trips to the dyno - I gave up wanted to try something else. Enter the stock 821's.

This new combo was picked as a cheap experiment. Still pretty bitter about what I spent on the last combo and wasn't looking to drop thousands more to try another cathedral set-up. If anybody gets to say I feel like it's me...

While I would like to look for more out of these rec ports I think it's a lot closer to hitting the mark than my last go around and I pocketed money for a quicker better driving car. I knew posting this thread would draw the usual offenders so they could continue their cathedral vs. square port debate...wether this is a apples/apples comparison or not isn't of any concern to me. Dollars spent vs results is.

Also, just wanted to add the DA on the 121.6mph pass was +1500 and the car is FAR from an optimized drag car. Completely stock configuration run on stock size all-season tires. Real deal street trim.

Tuskyz28

My car traps 121-124 now with a 370ci. I would expect faster myself with a 416. I'm also right now running LS3 heads/intake and properly spec cam.

74u

iTrader: (9)

For that to be relevant we would need to hear about your car, and conditions it ran in.

My car only trapped 127 on a 100 shot (570/588 wheel) the same day I did 121 on motor.

JakeFusion

iTrader: (7)

LS3 heads tend to like less overlap. So it's not surprising. What is surprising is that the cathedral port heads with more cam didn't do jack ****.

I also am assuming you're not losing fuel pressure up top or slipping the clutch? Do you know for certain both of those things are not happening?

If you are certain the clutch is holding and FP is steady, then I think your shortblock is holding you back due to blowby. The rest of the previous combo was good enough for 530rwhp, but it's never sniffed 530 and the trap speed indicates it's probably not the dyno reading low. So unfortunately, the shortblock is the one thing you haven't changed.

speedtigger

iTrader: (16)

Twelve and a half degrees is certainly less. LOL

74u

iTrader: (9)

Fuel pressure was rock steady (58psi) at 570rwhp on the dyno while spraying...I don't have a gauge in car to watch it on the drag strip but I can't imagine it falling off on motor if it held another 100hp on the dyno.

Clutch is absolutely locked up...no slippage.

I have to agree the shortblock is about the only common denominator but seems like if I was blowing by 50rwhp it would be smoking like a chimney, lifting the dip stick, rolling smoke out the fill cap when I open it, consuming massive amounts of oil,... something. Right?

The leak percentages weren't great, but I would think still within acceptable range.

Kip/CamMotion did offer a interesting possibility... the pistons are dished -15cc which substantailly reduces the quench area. I know my quench clearance should be 0.045", but not a lot of the piston meets the head.

These are the pistons... http://www.briantooleyracing.com/wis...re-k445x7.html

More suited to a boost application. If I understand correctly boost combos don't care about quench as much as n/a.

1989GTA

I would say with those piston your motor is set up for boost. You might want to give that some consideration using an LSA blower. I have been looking into it and the cost is not all that bad.

Problem is on my LS3 based 427motor I went with -4cc pistons which is suppose to put my compression ratio at 11.4:1. To high for any boost so I have dropped the consideration.

Anyways that looks like where some of your power has gone.

KCS

iTrader: (20)

He has 58cc chambers so his compression ratio is over 11:1.

Tuskyz28

nothing really special....
2000 m6 z28
370ci LQ block
Kooks 1 7/8 headers
kooks true dual exhaust system
Nick Williams 92mm throttle body
42lb injectors
Spare tire and Jack ditched
229/244 cam
Ls3 heads stock with Tooley springs
ported ls3 intake

I'm located right outside of Memphis which is my closest quarter mile track. So it does get hot and humid here. Car have been 11.6 spinning.....

Still learning the combo. Sorry for the late response. Working 12 hour days at a ammunition plant I don't have much freedom.

Tony @ Mamo Motorsports

OP....good response....I like the "I got ripped part".....LOL (and certainly you earned it with the previous combo!).

Have we ever verified the quality of the heads, flow, valvejob etc.....did you get them new? And I apologize if this was beat to death also but its kinda also obvious the heads were/are in question as well. Most of us would agree a "good" set of TFS 225 would have/should have made more power but perhaps it had something to do with the heads (me not knowing any of their history). Just a thought....

Anyway....I think yuor attitude is very good all things considered....it was a great learning experience for you, and one way of another when the smoke cleared your driving a car thats faster and more fun to drive....win win without a doubt (realizing that came with alot of blood sweat and tears obviously).

Would love to help you down the road if your ever in the market again.....mention this situation and I will see what I can do to help!



Cheers,
Tony

1989GTA

Yep, I forgot about the "milled to 58cc" combustion chamber.

62nalide

iTrader: (2)

I'm in DFW if you have any question bro.
My L99 (376ci) made 527rwhp 478rwtq on ported 823s and a Rick Crawford modded intake. My Car is a 5th gen and hit 6.80s in the 1/8 trapping 100-102mph and over 127mph in the 1/4.

gbtwo

iTrader: (4)

I'm glad you like the new combo but like everyone has stated there is still a missing piece yet. I also agree it's in the shortblock itself, because regardless or TFS 225 or LS3 heads, that 416 should be putting down 500hp @ the wheels easily. Thanks for posting the new numbers, very interesting.

The Dragon

iTrader: (6)

Tony what is a good hp/cube for a 402 or 416?

ctd

iTrader: (1)

I lived this first hand, the step I took was verifying the cylinders head were not up to the task. Your experiment worked out for you financially, it still leaves unanswered questions none the less........I did not win on the expense side.

Reading your comments about the pistons I had to go back & review what I have, mine are -10cc. Not much help with your -15cc for comparison.

Leak down, I do agree with your comments regarding crankcase pressure etc. I cannot find my leak down measurements, I know it was not perfect either. Discussion with Martin suggested a single puff compression test, have you tried that? I had a discussion with a drag racer friend that had a motor going away, they were doing a leak down as the weekend went on. It was getting worse, the interesting part was the car was going faster :-)

I'm on my third camshaft, the first was 17* overlap, the most horrible POS I've ever owned. The second cam was 10.5* overlap, much more tuner driver friendly & no loss or gain in power. This was the stage were I suspected the cylinder heads, it was verified they would never meet my goals.

On went new heavily modified heads with a very nice gain in power with the same 10.5* cam, no other changes.

My quest with this car is a perfect no compromise driver, no tune tricks to make a big cam drive @ the expense of cruise performance. So I have re cam'd it again, 5* of overlap. Much closer detail to valve train with springs, lifters, pushrods & rockers arms with Martins help. Driveabilty is perfect & average power is improved espically in the midrange. I'm just finishing up on the dyno with it now.

Do you have a next step plan?

slow trap

iTrader: (22)

have you thought about checking the cylinder that had 2x% leakdown and see what it is now ? i am thinking that cylinder was the reason for low power. could be rings but i am thinking the head on that hole had a bad valve or something out of whack causing all the leak down. if heads were checked and came out fine then that much leakdown seems alittle excessive but who knows.
glad it is picking up power now.