Nidz

G'day there from Australia.. I don't get on here that often but I thought I would bounce some ideas around here.. Recently installed a Comp 224/224 114lsa cam and some PAC 1218 springs to match. Had the car tuned nicely. AFR reading almost flat on and everything else checks out. Timing setup correctly. Edited using EFILive. I have a OTR intake with a hi-flow filter and at the back I have some Stainless headers into 200CPI 2.5" cats and topped off with a twin 2.5" Catback. Cam install went to plan, Valve springs and cam went in without a hitch. Dot to Dot install with standard timing chain. Some WOT tuning was done (off dyno). Brought my car in to a dyno day expecting to see some better figures than my standard LS1 cam. To my amazement the figures made were around about the same as the stock figures (about 214RWKW ~ 286RWHP). No strange noises from my engine, in fact my lifters are quieter than some newer cammed cars I know. The car is a 2002 model and has 145,000KM ~ or around about 90,000miles on the clock. I have been told after my my last run that I could have valvetrain issues.. Can anybody make any suggestions to where my next step would be? I'm no pro at this and I have a tuner who does a good job as far as I'm concerned. The car feels and pulls harder than it did before which Is why I was so amazed to not see any higher figures on the dial.. I do understand the difference between a street tune and a dyno tune and I do know that Dyno figures don't always tell the whole story. I just feel that there may be something overlooked. PS the before and after dyno was the same one.

MUSTANGBRKR02

iTrader: (91)

What size pushrods? What is your timing at? Who tuned it?

Nidz

Standard LS1 pushrods, Timing is set advanced.. I'm not really sure.. I can't recall.. +13 sounds familiar? Tuner is a person who is not a shop but has knowledge in tuning V2 EFI live and have had confirmation from the shop who dyno'd it that the tune does appear to be pretty good. I can post a dyno sheet if needed but all it will show is pretty much + or - 2 on the AFR and steady power increase. Does have low down pickup which might not show when dyno'd in 3rd gear (BTW it's a 4 speed Auto). The shop that dyno'd the car did confirm that it's a hardware issue of some kind and not software. I was thinking about taking my cats off and make sure there's no blockage in there however I doubt it. The cats have metal substrate and are welded in...

BTW apart from the Exhaust and intake, the CAM and valve springs are the only other hardware from stock. Stock manifold and TB... It's got a Mafless tune on it as well.

Patrick G

iTrader: (14)

Two things: You say stock pushrods...do you mean stock pushrod length with heavy duty chrome moly construction or stock pushrods that flex and bend under higher pressure than stock?

Have you checked all your ignition outputs? Plugs, coils and wires? Often, you will have a spark problem with one cylinder and be down on power.

HSVGTS300

One thing you didnt do was degree the cam.

MUSTANGBRKR02

iTrader: (91)

All though this helps there are thousands of cammed cars without this. It isn't necessary.

I was wondering about your timing in your tune. Are you speed density tuned or MAF tuned?

Nidz

Thanks for the replies.. The LS1 internals are all stock from the factory. The springs and cam are the only 2 things that have been upgraded.

I'm not sure if the tuning tool will advise if there's a spark issue or whatever.. I would assume that this would be picked up on the tune. The tune I have is a mafless tune.



Cam Install photos

http://s734.photobucket.com/albums/w...grade/?start=0

Last dyno run that only got me 214KW.

http://www.youtube.com/watch?v=NqYGFJInphA


I will check those things that were suggested. I have logged my dyno runs so I can review those results with my tuner...

MUSTANGBRKR02

iTrader: (91)

What is the reasoning behind a SD tune on a cam only car?

Nidz

http://www.oztracktuning.com/index.p...id=2&Itemid=30

This might help.

Also another explination from another site..

LS1 Edit MAFLESS TUNE is normally favored by those with competition applications in mind, where the stock maf tube and airbox can be replaced with a full ram air intake system. It puts your otherwise stock Commodore in 'HSV GTS' mode, and allows fine throttle response tuning.

LS1 Edit MAFLESS TUNE requires your vehicle be remapped and volumetric and ignition curves to get the best power and driveability from your vehicle. MAFLESS TUNE also requires indepth transmission calibration on automatic transmission equipped vehicles. Specific areas of tuning will include -

VOLUMETRIC EFFICIENCY AND POWER ENRICHMENT
ALL RELEVENT IGNITION TABLES
CAT OVERTEMP PROTECTION RECALIBRATION
MAXIMUM TORQUE/ TORQUE MANAGEMENT RESEST
TRANSMISSION SHIFT CONTROL (auto cars only)
SPEED LIMITER (VU series or UAE vehicles)
FAN SPEED SWITCHING
MAF ERROR CODE REMOVAL

MUSTANGBRKR02

iTrader: (91)

I know why people use SD tuning but in a car that is well less than 500HP the MAF would be another tool to use while you are tuning.

Did you measure for your PR's?

1979rs/z28

iTrader: (21)

You need to get some real pushrods in that thing. Not sure if I missed it but I didn't see you mention anything better than stock.

Nidz

Ok thanks for the suggestions guys.. Appreicate it.. Will consider pushrod upgrade when I could be bothered stripping the springs out again.. Will they possibly bring me more power? Can anyone recommend me a brand of pushrod that is good for a upgrade?

PREDATOR-Z

Your pushrods seem to be the weaklink, They flex too much under the springs pressures applied and can be creating valve float.
I would replace those ASAP.

smoothzee

Hey NIDZ

Aftermarket cams generally have a smaller base circle than stock cams, and therefore will need a longer pushrod. You stated that there are no strange sounds coming from the engine, but with pushrods that are too short, there should be. Maybe the valves were adjusted to eliminate the unwanted sound (ticking), and therefore could be too tight. That would keep the valves openand cause a subsequent loss in power. Just speculation...........maybe someone else can elaborate on this.

Maxoverdrive2

mathia

iTrader: (2)

You should post up the dyno graph. You can get an idea if there's valve train instability by how the graph looks.

An ls1 powered wagon... I want one!

macca33

I'm thinking that it could be a cam-timing issue and if not dialled-in, that could be your reason, but you'd never know it. That cam should be making around 250-260rwkw in an auto on one of our dynos and to be so low is a clear indicator of a problem.

Pushrod issues may cause it to be down on the power, but I wouldn't think they'd be costing it 30-40+rwkw and I'd also suspect that any 'drop-off' due to pushrod issues would occur higher in the revrange. Is the dyno graph consistent, or does it peak and hold the same peak over a wide rev-range?

cheers

LS1 Coupe

Just recently saw on another sight that someone posted almost exactly what you explained, he mistakenly put the stock cam back in. Even with stock pushrods you should have better numbers, may not be peak but still better numbers.

wytry

iTrader: (6)

WOW bet that dude was pissed when he figured that out ^^^

NC98Z

iTrader: (1)

Make sure all your plugs are firing and your not running on 7 cylinders.
Make sure your TB is opening all the way open.

maxspeed96ct

iTrader: (3)

Nice ride!

Id love to bring one of those to the U.S.