"The Mongoose" - 1 3/4" Headers To 1 7/8" Headers (447 rwhp and 431 rwtq)
11-02-2016, 12:15 PM
#203
Update: I've pretty much left the car be because I wanted to enjoy it while the weather has been nice. Now that winter is coming, I've decided to replace the cam. I reached out to Advanced Induction, and they suggested a 234/240 113 LSA cam. I also reached out to Cam Motion and they suggested a 232/238 111.5 LSA cam. I'm going with Cam Motion because I get half off because they used a bunch of the names I suggested for "shelf cams". I also reached out to Martin through PM and a FB message, but I never got anything back. Below is what Cam Motion had to say about the current cam and the reason the cam fell off so hard at 5,800 RPM's: I'm looking forward to seeing how much better the new cam performs. I will also be adding a FAST intake/TB, but I want to start with the cam change to see how much more I get out of it with a cam that's properly spec'd to the heads/setup.
In looking at your current camshaft, it is pretty obvious why the power does not carry well in the upper RPM. Your current camshaft closes the intake valve at 38.5 degrees after bottom dead center. This is really early for a performance camshaft in an LS1 like yours and is about the same as a stock cam LS1 camshaft.
If you would like similar driving characteristics and better RPM capability, I would recommend a 232/238 111.5+3.5 with .621"/.595" lift. This camshaft will also work good on a cylinder head with a strong exhaust port. This camshaft will have slightly better intake piston to valve and slightly less exhaust valve clearance than what you have now. Plenty safe.
In looking at your current camshaft, it is pretty obvious why the power does not carry well in the upper RPM. Your current camshaft closes the intake valve at 38.5 degrees after bottom dead center. This is really early for a performance camshaft in an LS1 like yours and is about the same as a stock cam LS1 camshaft.
If you would like similar driving characteristics and better RPM capability, I would recommend a 232/238 111.5+3.5 with .621"/.595" lift. This camshaft will also work good on a cylinder head with a strong exhaust port. This camshaft will have slightly better intake piston to valve and slightly less exhaust valve clearance than what you have now. Plenty safe.
11-02-2016, 12:46 PM
#207
Yes, new numbers will be posted. Pulls will be made on the same dyno too, so it will be a real comparison.
11-05-2016, 10:32 AM
#210
In looking at your current camshaft, it is pretty obvious why the power does not carry well in the upper RPM. Your current camshaft closes the intake valve at 38.5 degrees after bottom dead center. This is really early for a performance camshaft in an LS1 like yours and is about the same as a stock cam LS1 camshaft.
11-05-2016, 06:17 PM
#211
I agree, I'm usually not one to say "I told you so", but that's what I was saying since page 1. If the intake valve is closing too soon, you will not be able to take advatntage of the "inertia supercharging" effect at higher RPM/airspeeds. If you were to retard the cam a few degrees and it picks up power, that would confirm it.
11-06-2016, 12:54 AM
#214
Interesting. I haven't visited the dyno section in quite a while. Nice read.
That cam and heads combo was never great. Adding the 1-7/8" just made it worse. You need a later IVC... and I'll say this the I/E ratio doesn't really matter.
I went from a 234/242 111+3 to a 227/244 115+5. My IVC dropped and my exhaust events are even later. And I have pretty much the same exhaust as you.
I didn't lose a damn thing. I picked up everywhere. Even up top. I don't have back-to-back dynos to prove it. Just a VE table that required 20% more fuel down low and 5-7% up top. And a car that gets sideways even easier.
Why? Who knows. Tooley said I'd be faster with this cam with the TEA heads. It's now good for the D1 I'm adding too...
That cam and heads combo was never great. Adding the 1-7/8" just made it worse. You need a later IVC... and I'll say this the I/E ratio doesn't really matter.
I went from a 234/242 111+3 to a 227/244 115+5. My IVC dropped and my exhaust events are even later. And I have pretty much the same exhaust as you.
I didn't lose a damn thing. I picked up everywhere. Even up top. I don't have back-to-back dynos to prove it. Just a VE table that required 20% more fuel down low and 5-7% up top. And a car that gets sideways even easier.
Why? Who knows. Tooley said I'd be faster with this cam with the TEA heads. It's now good for the D1 I'm adding too...
11-06-2016, 09:46 AM
#215
I'd be very happy with those gains. After the cam change, we'll get the car on the dyno and touch up the tune and get some new numbers. Over the winter I will also add a FAST intake. I'm hoping Vengeance Racing offers their Black Friday sale where they offer the porting of their FAST intakes for free. I know they've done this in years past.
11-17-2016, 07:52 AM
#220
The car was dyno'd last night with the current cam/setup. It put down 431 rwhp and 421 rwtq with the cooler weather. The old cam is coming out and the new one is going in. I'll have dyno numbers Friday evening with the new cam. I'll make sure to get the graph posted.