lstvr

Hi Guys,

I have asked two respected guys for a cam on my 416Ci, and the duration has been very similar 239/248 118+3, and the other 246/250 110+2, but the LSA is very different, can anyone tell me which one would do what?
The Itb's can idle alot better than single plane, and will run smoother on cruise settings, thanks to lack of cross contamination.

Patron

With the added duration of the 2nd cam the LSA is tighter to broaden the TQ or peak earlier while the other cam would peak where the 246 would peak. The 246 cam would have a higher peak with more LSA....AKA: More RPM. Basically the same cam, ones just Fooled to think it has less duration. Also the longer duration cam will have a choppier sound.

lstvr

So the 118 is better? I don’t think I’ve seen a 118 cam before!

NAVYBLUE210

Which Heads?

lstvr

At the moment Dart 225’s that have been flowed, with a 5 angle valve job, but looking to move up to trickflow 245.

KW Baraka

iTrader: (7)

Well, really.....nothing about these cams are similar at all.

The 239*/248* cam is gonna have about 7* of valve overlap. Means the engine will have some noticeable but not unmanageable lope. Peak torque will be between 4500 to 5000 RPMs and it's hold good torque right up to the 6000 RPM range. Peak HP will be very close to 6500 RPMs. This cam will make for a real good track runner while being VERY streetable.

The 246*/250* cam will have 28* of valve overlap. It's torque curve will be less broad and will have more peak than the 239* cam. It will have a very rough idle.....even with a good tune. It should make more peak HP and TQ than the 239* cam and it's power will tilt more towards the top end of the RPM curve. This cam will be much more race oriented. You will still be able to drive the car on the street, but you're gonna have to put in work to do so.

IMHO......of course.

BTW.....what's your compression ratio gonna be?

KW

lstvr

We have 99ron fuel in the UK, so I’m going to run a .40 gasket to get me to around 11.8:1, my current cam in my sig is on a 114+3, that was specced when I had a fast 90 by thunder racing. I have a best of 10.63/133, 6.8/103 1/8th

NAVYBLUE210

I Agree with KW those cams are FAR apart in driveability and performance
Characteristics. I like the 239* Intake Duration with either TFS 245 or
MMS 235 W/NFI (also available with TFS) + 6-8* Exhaust will be more than
Enough for 7000 RPM with those exhaust ports. So 239/245 on a 114*+3* LSA. Overlap something Between 10-12* very easy to tune will get much better mileage than 246/250 110+ 2, and perform better all the way around with your light Car than either cam. I would expect 560-580 RWHP, Maybe +15-20 more with the ITB Manifold.

pantera_efi

iTrader: (1)

Hi TVR, my guess is the ABOVE TECH is FROM NON-ITB users or GARBAGE for YOUR CASE.

NOW, I agree with your "tech" and your cam choice (246/250) with even a 108 C/L being better. (@Split Overlap)
This will IDLE at 400 RPM if "sync" is balanced well. (little chop)

My ITB Bore is 65mm with that HP of 650-700 (bench) with the same specs as your engine expected.
What is your ITB bore ?

I could provide a Crower Camshaft ?
Nice car, your TVR.
Send us a picture

Lance

lstvr

Hi Lance,

I have 55mm chokes, its a real effort to set up just of idle, the split second you rest a toenail on the throttle it has to sense movement, all those chokes all of a sudden let in alot of air, yours even more so, otherwise it goes weak.
But yes it can idle down to 500rpm and be smooth still.
Thanks for the comments!

Paul.

NAVYBLUE210

Non ITB user but Admirere here.
55 MM ITB is in OPs signature.
Currently making 530 RWHP and wanted more power and better
Efficiency. (Suspect dual purpose Street/Track) With a HR &
~7000 RPM & Super Efficient Heads mentioned wouldn't an
Overlap range of 12-20* be ideal VS 28-30*? I Know the
Tuning ability with ITBs can handle much greater Overlap
VS Single Plane or Plastic Style but aside from the cool
400 RPM Idle and chop it would produce is there any
Trade off. BTW 560-600 RWHP is pretty close to
650-700 Bench/(Flywheel?)through a Manual Trans.
BTW Where is the Garbage?

pantera_efi

iTrader: (1)

Hi Paul, it would be very helpful if you could describe your Exhaust Header.
The primary tube diameter(s) and length, if known by myself, could then be matched to the intake diameter/length (???) better by a camshaft specification.

My ECU-882C has a fuel object that works well with ITB's, a enrichement based on SUDDEN RPM increase.
What is you ECM/Tuners Tool ?
Can you adjust the Injection Angle ?

Lance

Patron

So I'm not misinformed * with all the tech talk where would the 246 peak at VS the 239 we know the 239 should and would have a better ride quality @ 118 and more TQ. That's a free be.

DietCoke

iTrader: (18)

? I ran a 259/277 in a 430 on the street with a hi-ram. That thing will idle like a stock cam with ITBs.

Patron

I'm with you on that, my ? is for the cam Guru's as I thought and know that the LSA brings peak earlier for the 246 I just wanna where it would peak. Would it be around where the 239 peak at?

Patron

BTW Navy the Trash boy is here. With your 700 hp High dollar build and I'm trash my junk makes your build and heads look like .....No comment. You've been punked. The Factory for the win and Not the aftermarket. Destroke guy. Spend all that $ for 710 hp .
Go plug this into you CPU what does 260/272 with .730 do in a 408 @ around 11.8 comp. with Factory Ls3 heads do to you or your groupies. That's my junk yard build. Guru. I think you figure with the $ you've spent makes you a Guru or the next best thing since sliced cheese. If so then in the cheese world I must be smoked gouda. I'll be Your the garbage boy.

Asymmetrical roller cam do you even know or heard of this Cam guru's? I got you LANCE.

pantera_efi

iTrader: (1)

Hi Patron, I use Andrews Products for Lobe Design.
I have created Inverse Radius Roller Lobes, NO PROBLEM.
My guess is you think I am on Mushrooms, my cams, as they will SLAP a lifter with MUCH GREATER ACCELERATION then a roller.

NOW your question IS A SIMPLE Maths report 239/246 IN Lobe.

THE 239 WILL CLOSE the Inlet valve @ .050" with 54.5*
THE 249 WILL CLOSE the Inlet Valve @ .050" with 51*

THUS Patron, I agree with you, a better report followed by more engine specification required could be provided.

Lance

Patron

Lance I know you know and understand what was talked about. Me and a few others text about some of the BS that's just plain old BS. Some guy's on here think they know everything< I'm not saying I do but I research and ask more than most and have built or have made more crazier stuff than some of the BS spoken. They think every build is the same with the same basic BS combination= a 246 cam that has some ***** or stroke with ITB wouldn't be good. Let me get a build for Proof. I deal with facts not hearsay and the people who do this. Lance anytime I've asked you're on point case in point me Darth cam up with a cam combination for a 408 we said 850 you said that your computer said 845 at the RPM we said it. If you know a few combinations you can pretty much have or get what you what with anything. I give away 700 to 800 combos for free. Above that cost lunch.

402 ITB 700 hp 2009 Ls1tech I've read all the pages on this site. The good one's are Bookmarked.

https://ls1tech.com/forums/dynamomet...d-700-1hp.html

lstvr

Here is one of the manifolds, the other isnt off yet im working on it as we speak, will pull the motor this weekend.
Its 1.75" and i have to dent one of those to squeeze it past the chassis, the headers are 10 years old now, scruffy but they have no holes!

Patron

If you could get a stepped header the engine would like that maybe 1.75 stepped to 2 inches. It doesn't hurt for sure. They don't look too bad for 10 yrs and UK weather. LOL! Also seen you said you were thinking of moving up to TFS 245 heads. Consider having your heads ported and your in the same bed as TFS heads. The 245's are a little better with the valve angle. But Dart heads Should have enough meat to have some work done. I figure you could get 350-340ish cfm in the right hands(Maybe more). Which is more than enough to make some steam Cheap. G. Good still has me feeling sick over Factory Ls1 heads flowing 340ish. Sick!