Need Some Input (N/A Cam related)

[702GT]

I know this is not 3v 4.6 Tech related, but my crew here in Vegas really need some help on this one. So mods, even though it's not 3v tech, please let this one slide for a minute?

My buddy is very disappointed with his 2v build. I'll give all the tech info at the bottom. We think the cams are the problem, but I don't understand cam specs enough to know what's good, what's bad, and what does what. I know there's some smart people on here, I've seen them rant and rave when it comes to cam specs before, I'm really hoping they step up to the plate and explain what's going on inside my friends motor. He's $6k+ into his 2v, and the power he made is no better than stock with an off the shelf stage 2 cam. So here we go:

Block:
-Teksid .20 over
-Cobra Crank
-Manley Rods
-JE Pistons (Flat Top)
Heads:
-Stock PI Heads (Port & Polished - Bench Flowed 238 (I) 183 (E) @.600" lift
-Oversized Valves
-Manley Springs
-Compression: 12:1
Intake:
-Custom JLT CAI
-Accufab 80mm TB
-Edelbrock 90mm Plenum
-Edelbrock Victor Jr. Manifold (Port matched to heads & Polished)
Drivetrain:
-T56
-4.10 Gears
Exhaust:
-CAM Long Tube Headers 2 5/8" Primary
-Magnaflow True X O/R
-SpinTech 2 1/2" Roush Side Exhaust
Cams:
-Comp Adjustable Cam Gears
-Bullet Cams: Specs are as follows;

Intake/Exhaust
Duration @ .050: 238/235
Lobe Lift: .3056/.2910
LSA: 108
Open-Close/Open-Close
Timing Events @ .050: 13-45/47.5-7.5
Duration @.006: 278/273
Gross Valve Lift: .550/.525
Valve Lash (Hot): .000/.000
Degree Intake Lobe To: 106
​

This is directly off his cam spec card. We did degree the cams ourselves using a degree wheel and proper gauge, it's right on at 106, even confirmed the intake valve by bore-scope.
​

Here's his dynograph:

I'm not an engine building expert by any means. But I would think 2v ported heads would make more power than that. It kills me that I can't understand cam specs to save my life, but one thing I do understand is LSA. The more overlap you have in cams, the more air gets thrown from the intake valve back out the exhaust valve, and if I understand it correctly, it would improve the reach of your powerband, but decrease peak power made. Which is why I'm calling on the cam experts to step in and set this straight, to confirm the cams are or aren't hurting his engine from making more power.

His powerband looks great, the car feels good, but the sad fact is he's not making any more power than a stock PI motor with a set of Comp Stage 2 XFI's. The tuner fed it as much spark timing as it would take 'til it stopped making power at 310. So he's maxed out in timing with 91 octane.

If this was your 2v build, and you wanted to make the best N/A power you could with what is given, what kind of cam profile would you look for or want, and what brand/type of cam?

I'm going all out on this one, I want to get to the bottom of this. I'll be calling everyone I can to try and get this figured out, Livernois, BBR, Brenspeed, Modular Head Shop, I don't care who, I just want it explained!

Thanks for looking at this you guys!

 

[blue streak]

Wow...

 

[QWKSNKE]

Has anyone played with the tune to make sure that car is getting the right fuel it wants. Some engines like to run a little fat and some like to run a little lean.

Also, remember that a dyno is a tool. How does the car perform? My last engine combo I had in my 93 cobra did not make the numbers from a dyno perspective but from a track/street acceleration was a second faster in the 1/4 then the same engine with milder cam higher hp combo.

Dyno graphs are for bench racing. I would rather have a 310rwhp car run 11's than a 375rwhp that runs 12's. Get what I am saying??

 

[05stroker]

I know shit on 2v cams , but subscribing .

 

[702GT]

We did play with the tune. We gave it more fuel, less fuel, more timing, less timing, and it responded as a normal N/A motor would. Right now it's got as much timing as it will make power for. Fuel is 12.8AFR and with the high compression we don't want to lean it out more than that.

The benchmark was a similar 2v, except he's stock boltom and heads, running the same intake setup and comp XFI stage 2's, he makes 297whp, and that stout build up above makes 310. Their powerbands are exactly the same too.

 

[Mr. Q]

maybe it's not the engine/head/tune combo, where he's losing power? is the transmission tip top?

the 4.10 gears would show a hp loss...

 

[05stroker]

We did play with the tune. We gave it more fuel, less fuel, more timing, less timing, and it responded as a normal N/A motor would. Right now it's got as much timing as it will make power for. Fuel is 12.8AFR and with the high compression we don't want to lean it out more than that.

The benchmark was a similar 2v, except he's stock boltom and heads, running the same intake setup and comp XFI stage 2's, he makes 297whp, and that stout build up above makes 310. Their powerbands are exactly the same too.

Nevermind just saw the 550 lift . I would also hope for more .

 

[Sofakingfast]

loaded dynojet?

 

[GrnBullitt08]

If the car runs great and feels strong then I wouldn't touch it. I would expect the numbers to be higher near the 340-350 range but every combination behaves differently depending on who built it, spec design, and tuning.

You can try alternative cams to see if you pick up power, other than that I would leave it alone, power numbers dont mean sqaut if the car performs well.

 

[702GT]

I would normally agree, but considering the port work
done on the heads, we want to see at least 330. Hopefully modular head shop calls back tomorrow.

 

[QWKSNKE]

If the car runs great and feels strong then I wouldn't touch it. I would expect the numbers to be higher near the 340-350 range but every combination behaves differently depending on who built it, spec design, and tuning.

You can try alternative cams to see if you pick up power, other than that I would leave it alone, power numbers dont mean sqaut if the car performs well.

Exactly..

Also, I have to ask, was the dyno test performed in 4th gear? For some reason I have seen on this site where people dyno in gears other than 4th for some reason (or the appropriate 1:1 tranny ratio)

 

[JEWC_Motorsports]

I might be thinking in terms of old school but 12:1 comp on 91 oct does not sound right to me.

 

[GrnBullitt08]

I might be thinking in terms of old school but 12:1 comp on 91 oct does not sound right to me.

Not usually...once you cross over into that CR you usually up to race fuel or now a days e15 or e85 could be an alternative.

 

[702GT]

12:1 Is the compression the shortblock is spec'd for based on stock heads. Since the bowl is worked a bit, it's really more like 11.5:1. We're getting the head specs from the head shop as well just in case the heads are called into question. But 11:1-12:1 is still pump gas compression as long as you keep your timing under control. Even the Coyote runs 11:1. E-85 and race gas isn't really an option. We're still in a recession out west lol. Besides, E-85 is far and few between, not to mention you have to constantly check the quality of it, and even if you could buy it in bulk you can only store it for 30 day before you start having issues with hydrocarbon breakdown. We've had a few E-85 turbo cars here pop due to bad E-85. Stations don't sell alot of it, so it sits in their storage tanks for who knows how long. Any motor tuned for E-85 is going to take advantage of the 105 octane rating, which can be disaster if that octane isn't there. For a race car, I'd do it. For a car I'm putting on the street, it's just not worth going that far out of our way for gas.

For putting a shoe on the other foot, as example for those of you who say "Leave well enough alone," I say to you; If you put ported 3v heads and supporting cams on your car, and made 330whp, are YOU going to leave it at that? Or are you going to ask "why?" Give the 2v a little credit, 310whp on a dynojet is childs play for a stock 2v with aftermarket cams/bolt ons. We want to know why, even if we have to tear the motor down to find out.

I guess maybe this wasn't the best place to look for tech advice on the matter, this is after all the s197 forum lol, but I thought for sure some of you guys were ex-2v guys before you went 3v. It was worth a shot though. I'll update this thread when we find answers.

 

[S197gt07]

I don't know crap about 2v's either, but a P&Ped 2v head only flows 238 (I) 183 (E) @.600" lift?

I mean BBR's lowest form of Porting on a 3v head is 283 (I) 177 (E) @ only .500 lift.

Just my initial ponderings

 

[702GT]

I don't know crap about 2v's either, but a P&Ped 2v head only flows 238 (I) 183 (E) @.600" lift?

I mean BBR's lowest form of Porting on a 3v head is 283 (I) 177 (E) @ only .500 lift.

Just my initial ponderings

Shhhh you could start a flame war saying stuff like that.

Yes, my dear watson, 3v's outflow 2v's, just like 4v's outflow 3v's. It is the nature of the beast. 238 is a good port job on a stock PI head. Even Patriot stage 3 heads only flow 225cfm at .600 lift. Also, don't get lifts confused between 2v and 3v. .500" is stock for them, where .500" for us is doing serious work.

If you want to get serious in a 2v, Trickflow's twisted wedge heads have been seen to flow 299CFM (I) at .600" and 240CFM (E) at .600" but you're talking about a dedicated 2v enthusiast who would pay the outrageous cost for such heads. The trickflow's are more than capable of outflowing a non ported 4v head, but it carries a serious price tag.

 

[S197gt07]

*looks around for 2v guy on S197 dedicated site*

I think I'll live, but I didn't know for sure thats why I asked.

Good to know though. Always knew 4v heads were sick, didnt know there was that big of a difference.

 

[JEWC_Motorsports]

What size are the valves and what do the heads flow at 550?

 

[3vs197]

that doesn't seem totally out of whack for a PI headed 2 valve. Maybe a tad low but guys with the trick flow heads are only making 340-350whp and those heads are far better than any stock 2v head. Plus those cams seem awfully big for that motor. I wouldn't worry about it too much.

 

[702GT]

Both the intake and exhaust valves are 1mm oversized. The heads flow 238/183 @.600" we don't have the exact head data from the bench flow yet, we're getting those specs today.

Modular Head Shop seems to be too busy to talk to their customers, so I'm going to just have to keep calling 'til they get tired of me calling. I can't figure out why some vendors/shops can't take 10 minutes to work with a customer. I know many shops are very busy, but I need 10 friggin minutes, I'm not asking for a congressional hearing.