Fuel prices are climbing rapidly over here in Australia and I'd like to keep my LS1 on the road for many years, I want some suggestions for designing a max efficiency cam for cruising.

​​​​​​I have a rebuilt 99 Commodore LS1 6SPD LS1 3:46 bolts on 10:5:1 comp want to run on E10 fuel (94 Ron) same rating as your 91 octane (think 2002 Pontiac GTO in USA).

Desirable peak HP would be at 5500 rpm max or even a little lower.

I realize some would suggest a stock cam but stock cam tends to lower torque low in the rpms because of its wide LSA

What cam specs would be ideal?
​​​​

 

There is one cam that comes very close to what you describe; the Brian Tooley Truck Torque cam.
Specs are- 202/202, .511/.511, 111+1 LSA. In testing it gained 20# of torque throughout the measurable RPM range.
Where it differs from many low duration and OEM cams is its low LSA. Most Cam Motion truck cams, for example, AND OEM cams, have LSA's around 116 degrees, which kills low speed torque compared to the 111 of the Tooley cam. Yet the Tooley cam still has -20 degrees overlap so idle quality does not suffer. That is how low duration AND low LSA get on so well in this cam.
​​​​​​Does this come close to your idea of what a high efficiency cam is?

 

Thankyou 😊
It sounds good, where would peak rpm occur approx?

 

It peaks in a 5.3L engine at 5400 RPM

 

Thanks, I just checked the price of that one, it ends up being fairly expensive to get here to Australia, as a compromise I was thinking of the Summit Racing stage one truck cam, it has 209/217 at 36 IVC LSA 112 .550 lift and the same overlap as the BTR torque cam on -10. Although I'd prefer the BTR cam you mentioned .

 

The GT2-3 cam has been used by a few of us LS1 GTO owners back in the day.
great little cam with headers, UDP, OTRCAI.
I made 392 whp / 361 wtq with it.
Get HP tuners and enable lean cruise.
27-30 mpg.
Reports of quarter mile times is 12.1 to 12.5

 

Not bad considering the weight of the GTO. At first I thought you were talking about a Vette.
But it has a very wide LSA which cuts low end power, which OP would like to preserve as much as possible.

 

When my GTO had the GT2-3 cam and stock LS6 intake, stock 241 heads, drivability was excellent. I swear it felt like it was drive by wire. In heavy traffic, I could release the clutch without touching the throttle and would never stall. The benefit of this cam is the increase in lift vs stock. Plenty of exhaust duration. Power was smooth on the low rpms, then began stringers at 3500 rpm and up.

After reading all the theory of wide vs narrow, I still believe wide is better for a street car.
If the OP is concerned with gas mileage, narrow LSA has increased overlap, increased time when both valves are open. Wide spreads the power across the rpm range, narrow concentrates the power peak. So in theory if one wants some more power mid rpm at the sacrifice of low rpm then narrow makes sense.
But of course there is a lot more to cam design. Events, duration, ramp rates are part of the design magic that experienced designers impart in their cams.

 

The beauty of the Tooley cam I described, is that because of the low 202/202 duration, even a low 111 LSA will idle smooth due to the -20 degree overlap. It's the only low duration cam I've seen with that low an LSA. Cam tech keeps moving.
At the time it came out, the Lingenfelter GT 2-3 was ahead of its time with the wide duration split and high LSA that kept it smooth. The high lift sure didn't hurt things either.

 

Here is an interesting link there seems to be disagreement if high vacuum at low rpm is important for fuel efficiency.

Richards video (bottom link) on LSA seems like a lot of torque loss between the 112 and 120 LSA at 27 ft pnds but ends up being about 5 percent in reality. I wonder if that could be easily recovered in efficiency with less overlap better vacuum or some similar combination.


https://www.speed-talk.com/forum/viewtopic.php?t=14522

https://youtu.be/JUHwVCDjonU

 

Keep in mind that dyno tests are done at full throttle only.
And a cam that gains torque at a certain RPM will be more efficient than a "lesser" cam at the same RPM.
And throttle opening determines fuel flow. An engine that makes more max torque will require less throttle opening to make a certain torque number than an engine making less max torque.

 

One of things I noticed about many dyno tests posted on the net, you're not getting readings at idle to 2500 ( or 3000) rpm. ( Including my two combination / dyno runs)

So if the OP really wants gas mileage vs needing torque for a towing application, not sure either small cam will be significantly better than the other. (with good tuning.)

Unported stock 241 heads , compression ratio, hard to beat the result many of us achieved with the GT2-3.
Comparing my old combo to the new one, the GT2-3 had good torque starting literally at idle.
I ridden in a GTO with narrow LSA and the driver has to get the rpms up to avoid stalling, which means low torque.torque.

 

That cam reminds me a little of the LS9 cam although higher duration at 211/230 @50 122.5 LSA I'm a little reluctant as that one sometimes gets a bad rap as a poor man's cam that doesnt produce great results NA. Although I've heard of many good results from GT3-3 cam.

 

Actually the GT2-3 is a lot more conservative on split etc.

207/220 duration @ .050 lift -.571/.578 lift with 1.7 rocker 118.5 CL

 

The LS9 is a classic turd of a cam. It loses HUGE amounts of low end power due to the super wide 122.5 LSA.
Watch some of Richard Holdener's video cam tests. The LS9 and truck cam videos are eye-openers for opposite reasons.

 

I viewed the video it did best when advanced. I'm surprised anyone would use it NA.

USA appears to have better LS truck torque cams than here in Australia we don't have LS engines in trucks so most of the development centres on lighter vehicles.

 

OP,

The BTR Torque cam @G Atsma brought to the table is a good option for what you're looking for.

If you wanted something just as docile with maybe a bit more mid-range due to its 6* earlier EVO Cam Motion has a good option. That would be their CXM-03-01-0105. Specs on it are .527/.527, 200/204, 114+3 with -26* of overlap. It's designed to provide a performance bump for a 5.3 in a truck and maintain excellent driveability and fuel economy. That should fit well here for your needs. Powerband-wise, they should be similar with both having a 31* IVC. With some budget-friendly LS6 style springs either would be plenty happy.

Feel free to compare the two with our Cam Timing Calculator.

 

Summit- I would think any cam with -20 overlap @ .050 would idle like a stocker.

 

You don't have the issue of the lean cruise being enabled and intermittently going rich? mine does this and stays rich till i blip the throttle....

 

No disagreement there G. We fixed up that idle statement.