Mngnt

I'm building an LR4.

I got an LS1 cam (early model with .496" lift) for free with my LS1 intake.
I want to upgrade springs, as I don't trust the stock LR4 springs.

Swapping into my RX7. Don't want to "cheap out", but the ~50hp gain for "free" from the LS1 cam is too good to pass up.

Can I run the LS6 springs with the LS1 cam? $60 for the springs seems to be a great deal. What's the downside? Are they "too stiff"?

Unless someone can suggest a very cheap cam/spring swap that'll be better value than the ~50hp bump I should see from the LS1 cam... I don't want to spend $800 on a proper cam/spring swap at this point.

Thanks!

thunderstruck507

iTrader: (18)

They will be fine for what you are doing.

redtan

iTrader: (5)

Where exactly are you getting this "50hp" bump you keep mentioning? Certainly cannot be from putting it a measly LS1 cam...

Your best bet for OEM cams would be the LS6 or LS9 with the blue springs. Even with the significant lift and duration increase on those I really doubt you'll be seeing anywhere near 50hp on an otherwise stock 4.8

Mngnt

Using this thread:
http://www.hotrod.com/how-to/engine/...st-comparison/

63hp on a 5.3L should translate to 50ish with a 4.8, but we'll see.

At this point, for the $60 cost of LS6 springs, I'm happy with any improvement. With the swap I'll be doing exhaust & intake as well.

thunderstruck507

iTrader: (18)

Misleading really seeing as that quoted gain is at a point well past peak for either cam. A ls1 cammed engine should probably never see much over 6000rpm, much less 6500rpm. It's the gains in the 5000-6000rpm range you should be more interested in.

If it's free and easy to do I would still swap it if the engine is currently out of the vehicle. Free is free and fresh springs are good insurance either way. Should be a super easy swap with the engine on a stand and get you at least a little more power (and wider power band due to increase RPM capability).

For reference here is a comparison of my stock 5.3 cam to a Cam Motion 205/210 .510/.510 115+4 cam. Nothing was changed but the cam/springs and tuned for the cam (truck was previously tuned for the stock cam). You can expect lower gains with the ls1 cam due to both lower lift and stock lobe profiles versus the lobes designed by CM:

redtan

iTrader: (5)

That's cool and all, but how usable is that gain at 6500rpm? How long are you there for really (if at all)?

But hey, it's a free cam and should provide you some pep over the LR4 cam. Don't expect a major improvement, especially under 4500rpm where it apparently loses power.

Mngnt

All understood, thanks for the replies.

This is going in a 2800lb FC. I originally was after a 5.3/6.0, but this donor truck came up too cheap. Engine will be out, easy to swap cam.

Here's another question then - what would you do? I know the 4.8L likes to rev so I kinda figured a higher RPM cam would work, was planning on pushing redline to 7k. Not going to remove heads - engine has 140k km on it, runs perfectly.

I originally considered going with a Crane 224/232 .590" cam and springs, but then the "chinese turbo" threads came up, and that's a tempting move as well.

This is street only, hopefully DD. I kinda figured if I'm gonna spend $800+ on a cam & springs, why not spend $1200 and go turbo with more power than I could want?

That said, this is my first "fast car", so I'm sure I'll be happy with the stockish engine for the first summer... *crosses fingers*

EDIT: Thanks for the graph thunderstruck. I was under the impression bigger cams = tradeoff for less power at low RPM... this proves otherwise. Interesting...

redtan

iTrader: (5)

At least do an LS6 cam, it will provide quite a bit of boost with more duration and significantly more lift (yet still enough for LS6 springs obviously). Look at the LS3 cam in that article, it pulls 90+hp at the same level and it's slightly smaller than the LS6.

Plus that cam will work very well with a future turbo, many people do turbo 5.3s with the LS6 cam as it's cheap yet still good for that size engine.

If you were gonna stick with sub 6000rpm pulls they it probably doesn't matter, but if you're trying to spin an OEM cam to 7000rpm might as well be one of the best OEM cams available.

thunderstruck507

iTrader: (18)

I will preface by saying I am severely biased and have no use for a "monster" so I would never DD a turbo street car personally. I have had nothing but bad experiences with turbo cars in terms of reliability and hassle free enjoyment. It just seems there is nearly always something minor going wrong with them (or those chinese turbos giving up and failing possibly ruining the engine).

I would let my budget determine but either try to find the ls6 cam or a deal on a ASA or hotcam. Otherwise run the ls1 cam for now. If more funds are available, I would def get something from EPS or Cam Motion and try to get a bunch of usable power while maintaining street manners and disregard the turbo option.

Mngnt

Thanks guys, much appreciated.

EDIT: I'll keep my eyes peeled on classifieds etc.

MuhThugga

The LS6 cam is nice, but I would try to find an LS2 cam if you want to ditch the LS1 cam. They are cheaper than the LS6 and perform just as well. If you have the LS1 cam for free, I'd just get the LS6/LS2 springs for $60 and be done with it.

I just put a LS2 cam in a 5.3 I'm building. Partly because of that article, and mostly because I had one laying around. I'm anxious to see how it performs even though it won't be started for at least a year.

redtan

iTrader: (5)

Article seems a little bit off now that I got a chance to read the whole thing. An otherwise stock 5.3 with the LS2 cam produced 402hp and 399tq. Those are numbers you get out of a 6L LS2.

And 63hp (the equivalent of 50rwhp) from an increase of 12/19 duration and .050 lift. Seems a bit excessive when most people see 50rwhp from pretty decent cams in the 230s (an increase of over 30/30 duration and over .100 lift).

But hey, it's just an article and who knows how they got those numbers.

2muchboostNY

iTrader: (8)

It's engine dyno #s which might explain the inflated #s

MuhThugga

The LS2 was also used with exhaust manifolds and I believe they used long tubes in the article.

I also don't think they had nearly as much strapped on to the engine as is mandated for manufacturer ratings, but I could be wrong.


I wasn't really looking at the gains so much as I was looking to see what kind of numbers they posted in the lower RPMs, and the LS2 seemed to be one of the only cams to gain up top without losing much down low. I also had it sitting on my shelf, so that played a significant part in my decision.
"Do I spend $400 on a camshaft or do I put this one in there for free.99?"

redtan

iTrader: (5)

That makes a lot more sense if they had LTs and less accessories on there. And yes, for a free cam it's definitely worth it.