Who is a cam expert here?

[68Formula]

I made the mistake of telling you the total duration based on the moment the dial indicator started to move. I went back through my spreadsheet and calculated the duration and valve events at .006 lift. (keep in mind I recorded readings every 10* of crank rotation, so I did a linear interpolation to find anything in between, so there could be some minor error here, but hopefully not too bad).

So, due to my mistake we were thinking this cam was bigger (more duration) than it really is. It's still a very high duration cam, but the IVC happens much sooner (77.5*) than we thought initially with brings my DCR into the 8.1 range. here are my updated cam specs, I threw in the BG1 cam for comparison

Attachment 214189

The IVC and resulting DCR is not so bad. but the lobe separation is tighter by a good margin. This makes the valve overlap a bit more than the summit cam, and I assume this increased overlap would benefit from long tube headers and a more open exhaust.



Sorry to mislead you earlier, but what are your thoughts on this cam now....if any different from before. I'm thinking exhaust reversion is still going to be a big issue for me.

Cheers.

Corrrect: DCR much closer to where you want it; but still too late EVC and too much OL leading to reversion with the current setup.

[Zachalanche]

@68Formula
Gonna give this cam a go. thanks for your support.

[68Formula]

Welcome. Be sure to post the results!

Oh, and tell your tuner, "welcome" from me.

[Zachalanche]

Welcome. Be sure to post the results!

Oh, and tell your tuner, "welcome" from me.

lol. still need to get a clutch and some new mufflers and put it all back in the car. I also have an expired fuel cell I need to replace. and I now live 300 miles from my tuner, so it may be a bit before I have some results to post. but I'm eager to see what this car can do now.

[Zachalanche]

Well, a good bit of time has passed and the issues along the way have been plentiful, but I finally have this car back on the road, broken in, and tuned. Now, this is probably going to be the least scientific report out anyone has ever read, but here it is anyway.

I contacted the guy who initially tuned this car when it had the "custom" cam in it to see if he could update my tune for the new cam. He said sure but there was one problem he sold his shop and moved a few hundred miles away. lucky for me he happed to move to a place about 5 miles away from my house. So he came over and street tuned it. The downside here is that now I have no Dyno results to compare to the original, but I'm happy to report that the car absolutely rips now. It also pulls very hard until it hits the 6800 rpm limit, so I may raise that, but i think i'll do the trunnion upgrade to my rocker arms first.

Lastly for what its worth, My tuner said judging by the MAF readings he thinks the car is putting north of 525 hp to the tire. So who really knows, but the seat of my pants would believe that it has 65 more ponies than before.

Ill update this thread at some point once I have some 1/4 mile numbers, or dyno numbers to report.

[68Formula]

Well, a good bit of time has passed and the issues along the way have been plentiful, but I finally have this car back on the road, broken in, and tuned. Now, this is probably going to be the least scientific report out anyone has ever read, but here it is anyway.

I contacted the guy who initially tuned this car when it had the "custom" cam in it to see if he could update my tune for the new cam. He said sure but there was one problem he sold his shop and moved a few hundred miles away. lucky for me he happed to move to a place about 5 miles away from my house. So he came over and street tuned it. The downside here is that now I have no Dyno results to compare to the original, but I'm happy to report that the car absolutely rips now. It also pulls very hard until it hits the 6800 rpm limit, so I may raise that, but i think i'll do the trunnion upgrade to my rocker arms first.

Lastly for what its worth, My tuner said judging by the MAF readings he thinks the car is putting north of 525 hp to the tire. So who really knows, but the seat of my pants would believe that it has 65 more ponies than before.

Ill update this thread at some point once I have some 1/4 mile numbers, or dyno numbers to report.

Great to hear! That's the type of seat of the pants I was thinking. I bet he spent less time dialing it in too.

Please keep us updated when you get some numbers.

P.S. Should probably leave a rating for the cam on their if you haven't yet. Might help others.

[68Formula]

It also pulls very hard until it hits the 6800 rpm limit, so I may raise that, but i think i'll do the trunnion upgrade to my rocker arms first.

Both good ideas! Definitely do the rocker upgrade, and think about a 7000-7200rpm limit.

[68Formula]

Zach, ever get her back to a dyno for some numbers?

[Zachalanche]

Zach, ever get her back to a dyno for some numbers?

Negative.

I ran 2 tenths faster in the quarter mile (12.3 @118 - car weighs 3480 with me in it) this year at LS Fest in Las Vegas. but since I was in the Grand Champion class, they don't give us much test & tune time - 2 total runs. I was expecting more improvement, but I think I'm losing so much in the 60 ft trying to launch a road course tuned chassis on 200tw tires, its hard to infer real hp numbers from my drag times.

Last year they had a dyno there, so I figured I would get it dyno'd this year just for the data pt. but they didn't do the dyno challenge this year.

On the trackX course I definitely could feel more meat in the middle, and it revealed that my springs are now too soft as I was pulling my inside front tire way off the ground coming out of some of the faster turns. this wasn't something I was able to do last year. could be the engine, could be that my driving is getting better. could be both. hard to say.

[68Formula]

Cool. Too bad about them not having a dyno this time. What was your previous mph? That's a good indicator of a hp increase. And I'm sure the added meat in the middle is a nice added benefit on the course (once you get the chassis re-dialed in).

[Zachalanche]

116

2025 - 12.324 @ 118.36
2024 - 12.536 @ 115.99

what's that? 25ish more HP? seems less than expected. but still an improvement.

[Zachalanche]

I really wish I had done some data logging. Everything is pretty heat soaked by the time I get to the start line, I wonder if any timing is being pulled, and I might be missing some power that's there when the car is moving and things are staying cooler. but the same would probably apply to last years results so that part of it is apples to apples. I was also on 100 TW tires last year, but that didn't make a bit of difference in my 60 ft time.

[andrewb70]

I made the mistake of telling you the total duration based on the moment the dial indicator started to move. I went back through my spreadsheet and calculated the duration and valve events at .006 lift. (keep in mind I recorded readings every 10* of crank rotation, so I did a linear interpolation to find anything in between, so there could be some minor error here, but hopefully not too bad).

So, due to my mistake we were thinking this cam was bigger (more duration) than it really is. It's still a very high duration cam, but the IVC happens much sooner (77.5*) than we thought initially with brings my DCR into the 8.1 range. here are my updated cam specs, I threw in the BG1 cam for comparison

Attachment 214189

The IVC and resulting DCR is not so bad. but the lobe separation is tighter by a good margin. This makes the valve overlap a bit more than the summit cam, and I assume this increased overlap would benefit from long tube headers and a more open exhaust.

Sorry to mislead you earlier, but what are your thoughts on this cam now....if any different from before. I'm thinking exhaust reversion is still going to be a big issue for me.

Cheers.

I don't mean to downplay the discussion, but moving cam specs a little one way or the other is matter of 5-10HP on this engine. Fiddling around the edges of the cam specs is not going to be a 40-50HP jump.

What I have experienced over the last 5 years of tuning is that most people over cam their engines. The best bang for the buck are the three things that will impact power the most are:

1. displacement
2. heads
3. cam

Big engines with great heads and a modest cam result in the best overall combination for a street car.

Andrew

[streetk14]

I don't mean to downplay the discussion, but moving cam specs a little one way or the other is matter of 5-10HP on this engine. Fiddling around the edges of the cam specs is not going to be a 40-50HP jump.

What I have experienced over the last 5 years of tuning is that most people over cam their engines. The best bang for the buck are the three things that will impact power the most are:

1. displacement
2. heads
3. cam

Big engines with great heads and a modest cam result in the best overall combination for a street car.

Andrew

Thats more or less what I was going for. 427 cubic inches, Tony Mamo LS7 heads, and a 231/245 116+3. I’d like to get it back on the dyno, but this thing really needs a 3” exhaust.