00Vette04GTO

Hey guys,
So I posted this over at another forum site which I believe is affiliated - but then realized this site is probably where I should have posted.

I have a 2000 C5 A4. After failure of my engine builder to properly spec the motor - I have taken on the job. I wanted to see what cam specs you guys might recommend with this setup:

LS1 - Bored .005 over / Standard stroke
FAST 92mm Intake
90mm TB
42# Injectors
Trickflow Fast as Cast 220 Heads
Flat top forges pistons with 3cc valve recesses.
11.04:1 Compression
Comp cams 1.72 roller rockers
7.40 Trick Flow push rods
3000 Stall T/C

What duration cam would you guys go with for max power - while retaining drive-ability. My dyno guy is recommending:
236-238 intake
234-235 exhaust
110-112 lsa
.600 lift

Seems a little small to me... I want to use these good flowing heads. What do you guys think?


Here are all the specs for the engine if you want:

Bore size: 3.903
Stroke: 3.633
Head gasket: .050
Head gasket bore: 3.998
Valve recesses in pistons (flat top): .155
Valve Recess (cc): -3cc
Squench: -.017

Head Specs:
trickflow generation X
FAST AS CAST 220 cylinder heads for LS2
205.5 intake valve
1.570 exhaust valve
65cc chamber volume (milled down to 61cc)


First we need to break some things down.

Cylinder volume = 0.7853982 x bore2 (squared) x stroke

so
Cylinder volume = 0.7853982 x 15.233409 x 3.633
Cylinder volume = 43.46627286674899


Clearance volume = 0.7853982 x bore2 x squench
Clearance volume = 0.7853982 x 15.233409 x .017
Clearance volume = -0.2033929641438846

Piston dome or dish (valve recess) in cubic inches = cc's x 0.0610237
Piston Volume = 3 x 0.0610237
Piston Volume = 0.1830711

Head-gasket volume = 0.7853982 x gasket bore2 (squared) x compressed thickness
Head-gasket volume = 0.7853982 x 15.984004 x .050
Head-gasket volume = 0.62769039851964

Chamber volume in inches = cc's x 0.0610237
Chamber volume in inches = 65 x 0.0610237
Chamber volume in inches = 3.9665405

Then we take this formula:
Compression Ratio =
Cylinder vol. + clearance vol. + piston Comp. vol. + gasket vol. + chamber vol. divided by Clearance vol. + piston vol. + gasket vol. + chamber vol.

So:
Chamber volume in inches = cc's x 0.0610237
Chamber volume in inches = 61 x 0.0610237
Chamber volume in inches = 3.7224457

Compression Ratio = (43.46627286674899 + (-0.2033929641438846) + 0.1830711 + 0.62769039851964 + 3.7224457) / ((-0.2033929641438846) + 0.1830711 + 0.62769039851964 + 3.7224457)

Compression Ratio = 47.7960871011248 / 4.32981423437576
Compression Ratio = 11.0388308860128

Compression Ratio = 11.04:1

squirlNUTZ

Brian Tooley is, in my opinion, the person you should contact for your camshaft and TFS head.
http://www.briantooleyracing.com/
He has the most experience with this head. Although I'm sure many will also give Martin at http://www.tickperformance.com/contact/
As a camshaft recommendation.

00Vette04GTO

Thanks for those references! I will travel down that road and see where it leads me.

dr_whigham

iTrader: (49)

Ed Curtis or Brian Tooley. Both of them would go CRAZY with the detail you've given.

My cam is HALF the size of the one's you have posted, and you think they're "small"?

00Vette04GTO

Just left a voicemail with Brian Tooley..

And as far as cam size... I guess it's all relative... But I just didn't want to go through all of this and not spec this right. A lot of money has gone down this hole so as everyone - just looking for maximum $$$ to HP ratio.

(I had a 226 229 .600 lift @ .050 112 lsa and did not cam nearly as much as I expected and definitely was missing some power I expected.)

The reason I ripped it all back apart and started over is because the builder didn't calculate the lift correctly and bottomed all of my valve stem seals on the valve guides. Figured while I'm here I'd up my compression to 11:1 and up my cam. Just looking for that magical number. (and I know its different for everyone)

squirlNUTZ

True that

00Vette04GTO

Who is Ed Curtis with? Any contact info for him?

94 White T/A

Flowtech Induction (FTI)

00Vette04GTO

Thanks!

JakeFusion

iTrader: (7)

Something like what I have would work... EPS 234/242 .605"/.605" 111+3 LSA...

In fact, Brian Tooley and Martin Smallwood both have shelf cams that are very similar. 235/242 111 cams.

To me, that's the best balance of all out power while still being somewhat streetable. 16 degrees of overlap is still quite a bit tho. Just throw a **** ton of compression at it and get a good tune. And presto.

TT427

iTrader: (1)

Some things I see, that bother me a little, not enough stall for cams being suggested, and those rocker arms will likely be a handicap on agressive cam lobes. Also would like to know what gears you have...

garygnu

I agree, the stall is small .a smaller EPS cam could make 460 +rwhp .after you buy a cam measure for the correct length push rod.

00Vette04GTO

Yea... The stall was originally speced for another Cam. Would love to not have to change it, but will do what I need to. All depends on the max I can run with this stall and the tradeoff.

I have not heard that these rockers will hurt me on aggressive lobes. Why is that?

I believe I have a 3.42 rear end. (looking in HPtuners at final gear ratio.) Please lead me down the right road if this is not correct. I purchased this not too long ago so still learning LS engines, Corvettes, and HPtuners. Former ford guy here. (I dont discriminate)

Thanks for all the help you guys are providing! Ready to purchase but waiting to get some opinions.

JakeFusion

iTrader: (7)

3000 is pretty small. I didn't see that.

4000+ for anything in the 234/242 range...

And stock rockers are what I would recommend with the Comp/Lunati/Summit trunion kit.

RonSSNova

iTrader: (3)

You need to just look at the tag on the differential to see what gear ratio you have, C5 A4 came with 2.73 or 3.15, unless someone changed it.
If you put the cams mentioned in, anything over 230 on the intake and you aren't going to like the 3000 stall, you will want more like 3600-4000.

Ron (from that "other" site)

00Vette04GTO

Hey Ron (from that "other" site)!

Just looked and the rear end is tagged 3.15... Not sure if it was changed before I purchased. 3.45 in HP tuners on Final Gear Ratio.

Sigh... These torque converters are not cheap!

TT427

iTrader: (1)

They are heavier than stock, harder to control with on modern high intensity lobes.
I would look at something like the hellraiser or ssht from FTI, or something speced from someone similar but being and smallish stall would keep it under 230, but the experts would have more insight for this app and the handicapps you may be facing combination wise.

00Vette04GTO

Doing some research now that you have said that - I do see people have problems with them floating the valves... Wonder why that is?? I was under the impression they were lighter than stock from the description on Comp's site:

COMP Cams® has been a major proponent of steel rockers arms for many years, however with recent developments in the design and manufacturing of aluminum rocker arms, it is now possible for us to offer a premium aluminum rocker alternative. COMP Cams® proudly introduces the new “Gold Standard” in stud-mount, aluminum roller rocker arms – the Ultra-Gold™.

• The most advanced aluminum rocker arm ever; incorporates modern design features
• Lifetime warranty - buy them once, use them for a lifetime
• CNC-machined, lightweight design yields unrivaled quality & ratio accuracy
• Additional clearance versus competitors – clears most popular performance valve springs
• Proven to withstand extremely aggressive spring pressure and valve lift


Guess it wouldn't make sense for them to say they are crap on their site tho, eh?

AnotherWs6

iTrader: (17)

This thread is getting a bit long, but still a good read.

https://ls1tech.com/forums/generatio...rformance.html

People seem to be pretty happy with these guys.

JakeFusion

iTrader: (7)

The stock rockers are very light over the valve. Roller rockers are not.

PAC did some spintron testing on a roller rocker vs stock. They didn't disclose the rocker, but the stock rocker went out of control 2000 RPM later than the roller rocker with similar spring pressures. You have to have a lot more spring pressure to control them as well as stock. The problem is, they are aluminum and don't like those pressures for a long time. That also wears everything else.

Now, the stock rockers have some issues like side loading the valve which is bad with bronze valve guides (which I think is overplayed based on first hand testimony) and they scrub the valve tip pretty good over .630" lift (which is a real issue).

I'd look for endurance lobes with healthy lift (.590-.620 range) so you don't loft the lifter and destroy the lifter/rocker/cam from the thrashing and run stock rockers w/trunion upgrade (to alleviate the one known issue - spilled needle bearings), lightweight valves for easier valvetrain control, good lifters that can take a beating, and stiff pushrods (stiffer than the 5/16" spaghetti noodle **** everyone tries to sell - again spintron testing shows it's not nearly stiff enough).