GM LS1 Upgrade

[robmcg]

Wasn't sure if this belongs in 'Performance Muscle' but here goes.

I have a 2001 LS1-engine GM Australian Commodore VX factory-fitted LS6 intakes with freer exhaust otherwise stock. A4 3.07:1

Current cam is lovely flat torque, max 195rwkw@5,700-5,900 and it's strong but not strong enough!

I need better grunt in the 2,000-5,000rpm ... the engine needs a minor bearing idler thing now (it wouldn't happen on a Toyota) at 115K kms and I thought a bigger cam, e-tune and 3.45:1 would be good.

Current cam from memory is 194/200 .490 112? which works well and has really only 2nd gear on the road to do anything legal.

So here is a plan:
Rapid Motosport Dominator cam package about US$1,100 plus post these seem to come at
218/224 .578 114 or around 210/216 .525 depending on where you go on their website ...

Stock air intake since it's usually quite cool air in Canterbury NZ here unlike Australia. I already have the stock VX International exhaust without cats (legal here) and it has a good resonator behind two freeflows, sounds almost like stock, no resonance/drone.. and much of my driving involves listening to music.. or talk, or just being quiet generally

ECU re-write to suit RON 95 (USA 91 ?) with shorter gearing to 3.5 or 3.7 with the 4L60E it should if the timing and fuel is written right be tighter faster and better./ then maybe lower the car 1" approx and

the issue is, how far do I go with the cam for midrange? LS2s seem to take the longer cams well with skilled ECU writers... but the LS1 cam change I welcome advice.

[robmcg]

Nobody makes mandrel bent pipes for the very complex angles from the stock manifolds... which are fine, and we are not looking for great effort no real effective improvement in midrange.

I spent a lot of time making Lucas electrics and distributors work well ...

ideally I would prefer to plug in a notebook and 'read' the car ecu.
If by some method I could re-write things, much as you could replace Lucas bits, without the obession with max power and dynos, and change the GM timing a fraction.... THAT would be like openware computing like GM will never give up!

[Jim Rose]

>>I spent a lot of time making Lucas electrics and distributors work well ... <<

You'd have been better off had you spent the time getting Lucas referigerators to work well--- then at least you would have had a decent cold beer!

[robmcg]

>>I spent a lot of time making Lucas electrics and distributors work well ... <<

You'd have been better off had you spent the time getting Lucas referigerators to work well--- then at least you would have had a decent cold beer!

I got Lucas fine.
To set up a BMC Mini I had to have maybe a dozen distributors. None of the springs or vacuums were the same... so I tuned my own piano.
Same with springs in the distributor.

How the hell do I find a GM tech guru who will give me numbers on a computer? Half of them are paid big money for racing ... and the rest don't care.

So. I have to trick my way into getting a clear line to the numbers and settings, and guess what? the computers which allow access are currently owned by GM and they charge multo dollars like tens of thousands for the numbers so only the rich and stupid go there are guesses on dynos...

This is like saying, "sorry you cannot buy new springs for the distributor.. it violates law".

It makes Bill Gates look, well, the same, except GM doesn't have the market.
We cannot tune our cars except by dyno / test which is like saying, "GM has a fixed setting and alternative settings are illegal"..

Kids have nothing to do with American cars here, they see the GM/Ford sedans as silly. You cannot tune them.
And you wonder why.... I feel like some neanderthal driving a GM sedan.

Sure you can put the bits in but the electronics? Forget it. You are looking at huge resistance to change in factory settimgs, which makes Stalin look benign. And you wonder why you don't sell cars....

[Eric]

Morning!

Your planned project sounds fun!

I have little direct, hands-on experience with these LS-series V-8s, but my understanding is their chief virtue is superb airflow - allowing relatively mild cams to produce immense power (450-plus is easily obtainable, or so I have beent old).

I personally have never used a hotter stick than 280 degrees' duration in a street-driven car, but these were all old "old" V-8s that have nowhere near the VE of what you are working with - at least, not without aftermarket heads and serious porting.

Have you considered just adding a supercharger? It might be less expensive - and will certainly provide you with massive low and mid-range torque without affecting top-end power or driveability in the least.

[damen]

Well rob, if you dont mind being a bit limited you can get one of the diablosport predator handheld tuners. I have one for my Corvette and have been quite pleased it. You need to know what you're doing, but it will allow you adjust quite a bit - not as much as a real system, but it isnt too bad.

If you want to tune via laptop, I think what you need is LS1Edit (if I'm remembering correctly).

Eric is right, supercharging is definitely a great way to go with these engines, but I've always been a fan of Naturally Aspirated power myself, so I dont think you can go wrong.

[robmcg]

Thanks Eric and Damen,

Eric the supercharger idea is good except for a fatal flaw; it LOOKS bad unless the full-house thing on the middle of the engine and can lead to all kinds of tuning fueling issues, and then it isn't really an everyday car. I think 230rwkw is acheivable without having to upgrade the fuel and more importantly a stronger mid range 3,000-5,000rpm shouldn't hurt the drivetrain.

Serious guys down here go LS2 L76 with 90mm throttle cam etc and get 300rwkw which is, um, 430hp at the rear? Which they put often through a T56 6-speed and a 3.9 rear and get 10s with cars the same size as the GTO.

Damen I'd love to know about any editing tools I can plug into my LS1 PCM., even if they are limited in what they can do. The car is out of GM warranty. The tools to set mixture and timing...

I'm waiting for ideas from

http://www.ls1.com.au/forum/forumdisplay.php?f=9

otherwise I'm gonna buy a cam kit from America at about $1K + post with a 212/220 max .525 and try to bolt it together well.
As always it's tempting to go for the bigger cams, but I only went that ay with my BMC Mini A-series engines when I REALLY knew what I was doing... I even got a 288/288 A-series (that's full duration not 0.050") to idle and pull a 2,200 stall converter and with the Mini weighing about 900Kg that 4-speed auto was FUN.

[robmcg]

Here are the number for a local cam, Crowcams no.871265


Cam number 871265
IN.21/65 EX.72/20
Duration:266 273
at .050 214 221
I/C 114 deg
valve lift in..518" ex ..525"

springs required K871 pushrods PR957-16 stock retainers and rockers.

From memory the stock cam at 0.050" is 194 200 .495 lift which is mild but still runs very well, even if the stock springs and rods aren't too flash at the high end...

The crowcam set would cost about US$900 delivered excluding fitting and PCM or ECU rewrite..

They have a slightly tamer cam;
no. 871259
IN.20/60 EX.66/18
duration 258 265
duration 0.050" 207 213
valve lift .510" .518"

So I guess I'll talk to some of the local guys here who know a bit more about it.


There's a CompCams 265 cam which is comparable but last I looked a kit was $US1,000+

[Eric]

I'm not sure what's available down under (or the relative cost) but here in the US, the supercharger kit(s) for the GM LS V-8 are very well-engineered, fairly inexpensive - and deliver huge power gains without affecting either emissions legality or driveability at all.

Tearing into the engine to do a cam change may involve a lot more money (if you are paying a shop to do the work) and very well could involve hassles with the ECM/programming (if it's not done right) and screw your driveability and emissions....

I'd talk w/some people about your options before committing....

[damen]

with the LS1, pretty much any but the most mild of cams will require a dyno tune

[robmcg]

Thanks for the opinions and advice.

Eric I'm no big fan of forced induction unless the car is designed for it in what would be very expensive mods to the GM/Opel -derived Australian VX Commodore.. there are systems sold he for $A4,000-$5,000 here but they don't have the beauty of factory dedicated systems, or add-ons with A LOT of money and time. I enjoyed a 300ZXTT Nissan for awhile in 1998...

Damen what do you think of mail order 'flash' tunes for a cam as described in my post which in the Crowcams 214/221 114 setup can be done for around US$1,200 including ECU re-write? +my labour fitting + incidentals like seals /timing chain /oilpump cleanup/fluids ?

This is a fairly mild cam with lowish lift at .518/.525" but with a tune for 95 or 98RON fuel (US91 or 93) and ought to flow a ton more air than stock at modest revs and with the right timing... so long as the writer knows that he is doing!

I'm not all that happy with what must be a 'best guess' when the whole engine is only known approximately, but hiring a dyno and someone with the tools and knowhow to rewrite things ain't cheap!
Oh for the Lucas dizzies and SU needles of the past.

[damen]

I've never been a huge fan of the mail-in flash tunes, to be honest... but if you can find a GOOD tuner, then it will be fine.
The cam specs you've listed... arent bad. that really is an extremely mild cam - just a little bit more than the stock corvette z06 cam. I expect you'll be quite happy with that.

The price is high by the standards here in the states, but I dont know how it is there, but either way you're not being ripped off at that price either.

[robmcg]

I've never been a huge fan of the mail-in flash tunes, to be honest... but if you can find a GOOD tuner, then it will be fine.
The cam specs you've listed... arent bad. that really is an extremely mild cam - just a little bit more than the stock corvette z06 cam. I expect you'll be quite happy with that.

The price is high by the standards here in the states, but I dont know how it is there, but either way you're not being ripped off at that price either.

Thanks Damen,

Like you I am better suited to going fast on a sports bike than Eric. Iyengar Yoga... used to do weightlifting and med dist racing.. both running and wheelchair

The 'chips' or 'flashes' added to factory tunes are mostly around advanced timing richer mixes at low revs without changing what the facory tune includes.

Like comparing Win 3.1 with WinXp... so after talking around and my main love is music.. I have spent weeks trying to work out the value of relatively simple mods to cars like ECU or what some call PCM (Electronic control unit. Vehicle-control module. whatever)... and have learned a few things from the guy who tunes GM and Ford V8 racecars here from a short time with his ear... he is off to races this weekend... the phone-girls protected him from my enquiry... but then by luck his employer answered the phone at lunchtime and got
well,
he thought I was Bert Munro

when I mentioned the britbikes.

I have a few thoughts about modifying things,

he was very pleasant as he talked with me about closed loop changes

I still don't know if a 'chip' or a 'flash' has any value. Seems you need a full dyno tune ... even if you want just to improve things on part throttle you are dancing in the dark when you go there. factory knows best.

I might install the cam anyway LS1 215/221 to give a good airflow with .520-.530 ift 114 and see what happens.

US sellers concentrate on longer timing higher lifts, but my feeling is that stock LS1 + chip if that fails change the ratio on the throttle.. but all is based on full throttle stuff. What I want is better timing and mixture on part throttle safe and better top end...

Probably in the wrong thread..

Rob

[robmcg]

I have bought Crowcams

8712651a
IN.21/65EX.72/20 266 273
214 221 .
518" in .525" ex. valve-lift

with springs and bits the key be is that at 0.050" 214 this is very mild to make the car breathe better with springs and stronger pushrods, which is much like I made BMC /minis with approrpriate fuel and timing, but is fun.

Fun! Without many dollars.

http://www.ls1howto.com/index.php?article=23

Best,

Robbie

If the above link works, you don't get better.