Andrews V6 Cams?

[oneuptom]

80" stock stroke Evo XL

My intent would be to set the initial CR at 11.5-1 and then back it down if needed, but wouldn't want to go below 11:1

Not interested in any cams with more than .500 lift, but more duration would be ok if needed

I also want to get the cams right the first time, so anyone with experience running these V6 cams at a similar CR what's your opinion?

[JBinNC]

I have built two 1200s with that 6 grind. At 10:1 or 10.5:1 (don't remember exactly) each made 90+ HP. You will need a decent cylinder head to get there, but this is a relatively easy combo to do, with good results. With the extra cubes you are planning, moar cam will probably be to your advantage, but that would mean you would have to add lift.

Jim

[oneuptom]

I have built two 1200s with that 6 grind. At 10:1 or 10.5:1 (don't remember exactly) each made 90+ HP. You will need a decent cylinder head to get there, but this is a relatively easy combo to do, with good results. With the extra cubes you are planning, moar cam will probably be to your advantage, but that would mean you would have to add lift.

Jim

I think you're right. I'll do a virtual build later to get a general idea of cylinder pressures, but the problem is that it doesn't account for exactly how good your heads are and how good the squish is.

I want to run the least pressure single spring possible and have it stone reliable at high rpm for long periods. I'd like to see 105/105 TQ/HP. Lots to consider. Thanks Jim

[oneuptom]

I modeled it with the V6 cams and 1.9 intake, 1.615 exhaust valves, mid RPM torque. All the cylinder pressures look good. I think this would make a nice street motor in a lightweight chassis !

[oneuptom]

I have built two 1200s with that 6 grind. At 10:1 or 10.5:1 (don't remember exactly) each made 90+ HP. You will need a decent cylinder head to get there, but this is a relatively easy combo to do, with good results. With the extra cubes you are planning, moar cam will probably be to your advantage, but that would mean you would have to add lift.

Jim

I played with the cam timing a bit more

The V6 cam is maxed out in this motor so moving the timing events around doesn't change anything much except for at 3 degrees retarded the dynamic CR is lowest so I think that's how it should be timed. The motor is a 89 so the timing is easily moved just by slotting the pinion gear to another position

[oneuptom]

It was interesting comparing the bigger looking V9 .555 lift, 266 duration cam with the smaller V6. They make exactly the same power because the V6 has just as much area under the curve and will be gentler on the valve train. Explains why Andrews is putting the V6/N6 up as their best Evo XL street cam now.

[JBinNC]

Most of that has to do with where the ports stall. If the port won't flow any more above, say, .500 lift, there is no need to lift the valve further. With roller cam profiles, you can max out the area under the curve without adding lift. If you did your analysis with a different head, the 9 grind might look much better.

Jim

[oneuptom]

Most of that has to do with where the ports stall. If the port won't flow any more above, say, .500 lift, there is no need to lift the valve further. With roller cam profiles, you can max out the area under the curve without adding lift. If you did your analysis with a different head, the 9 grind might look much better.

Jim

There's something to that, but shouldn't the stock ports be big enough already? This model has bigger 1.9 intake valves and the throats have been opened up to 1.627". I think anything bigger would maybe start to hurt velocity? I don't see the 9 grind still being offered anyway, was only curious. I'll try some bigger cams from Hammer without changing anything else

[oneuptom]

The big .660 lift Hammer cam will start making lots more power above 6800 rpm, but not until.

Checking all the way to 7,500 rpm (don't plan to run this motor past 7000) the V6 & V9 are making exactly the same power.

The .660 Hammer cam is indicating this model isn't flow limited

[oneuptom]

Dan from NRHS

"I have N6 cams in my personal 2007 Sporty with stg 2 light 1200 heads and one of our 1250 kits with 10.5:1 cr. They are nasty cams!! More redical than SE 536 cams. Pull all the way to 7,000 rpms but be warned they are not happy at anything under 3,000 rpms.", "VERY lopey!!!"

[oneuptom]

Dan from NRHS

"I have N6 cams in my personal 2007 Sporty with stg 2 light 1200 heads and one of our 1250 kits with 10.5:1 cr. They are nasty cams!! More redical than SE 536 cams. Pull all the way to 7,000 rpms but be warned they are not happy at anything under 3,000 rpms.", "VERY lopey!!!"

Thanks to Mr. Dan I stopped looking at the V6 cams. I also couldn't find a way to optimize them for pump gas.

So after trying countless other CAM/CR combos (for several hrs I must add) I found the ultimate pump gas combo for this bore/stroke/heads.

Andrews V8 cams installed 2 degrees retarded ,they come ground 4 degrees advanced (to preserve some bottom end on stock motors I would assume)? and a 9.5:1 CR is the absolute best!!! HP 106 @6,800 RPM - TQ 90 @3600 RPM. The cams sign off abruptly at 6,800 RPM but that's fine. Nothing else I looked at made as much TQ-HP under 6,800 RPM. This thing should be a beast from right off idle. Only downside is no cool rumpity rump idle like was wanting.

[JBinNC]

I just ordered a set of #4 grind for a 1200 motor I am rebuilding. I have 10:1 pistons for it, but may dish them a little to make the motor more street-friendly. I think the #8 uses the same, or very similar, intake specs? In any event, I think we are on the same page. I would like to hear more about your combo when you get it together. (By the way, I find the #6 to be very streetable, plus good to 7500 rpm.)

Jim

[oneuptom]

I'm curious to compare our different models to see what the dynamic CR is for yours, and to know which one will be more pump gas tolerant.

The #4 is ground 3 degrees advanced on a 101 LCA and has a bit shorter exhaust, otherwise they look the same.

[oneuptom]

Jim

At 9.5:1 your Dynamic CR is 8.508:1 HP 94, TQ 80 ft lbs

At 10:1 your Dynamic CR is 8.950:1 too high for how I see it!! and with no power increase because the program has probably pulled timing

Installing those cams straight up with a static 9.5:1 gets you Dynamic CR down to 8.375

I'm showing a Dynamic CR of 8.328:1 for my build