Can the LQ4 be tuned for 91/ 93 and make the same power as an LQ9?

 

All things being Stock, NO.

The LQ9 has .5 point more compression as well as a slightly larger cam shaft.

 

Disagree.

A tuned stock LQ4 will outpower a stock GM cal LQ9. Factory rating was only 10 hp different.

 

Disagree all you want. The difference was around 20 HP according to the factory rating.

Depending on the year the rating is from 300-325 for the LQ4

The LQ9 was rated at 345 HP.

So if you have an early one with Iron heads that's rated at 300HP Its going to make as much or more power than an LQ9 on Just a tune and 91 Octane???

 

The 300 hp version was detuned for noise requirements or something along those lines

Also, the LQ4 was rated up to 335 hp in 1500 apps and the LQ9 345.

years ago Allen Nelson took a crate LQ4, tuned it and put on engine dyno and made around 400 hp.

Note, as you seem to be a tad confused on what I'm saying; I am discussing a tuned LQ4 vs stock GM cal LQ9 (which is what I inferred the OP to be asking).

 

I am Straight, not confused the way you are...

An Iron Headed motor won't take the timing like an aluminum headed motor.

And yes you inferred the question he asked correctly.

Allen allegedly gained approximately 56 HP/ 50ft lbs on "His tune" with 31 degrees of timing on an 04 LQ4 with a DBC and an 02 PCM. Since he did not specify we can only assume it was on 93 octane Texas?

CA only has 91 Octane and most of it contains 10 ethanol. And if you only buy from lower end gas suppliers I can only imagine the tuning night mare it would create on any engine.

That being said, I run my Bone Stock LQ9 truck on 87 Octane with no issues.

Even with a tune I can physically till the difference between my Bone stock LQ9 and a tuned LQ4.

Were all entitled to our opinions right or wrong.

 

The only difference between the later LQ4's and LQ9s was the piston and half a point of compression because of the flat top versus dished. Any decent running LQ4 will make very close to the same power as a 9 mod for mod. Even the half ton LQ4 tune had the worst timing curve ever in an engine and still made within 20 hp of the LQ9 with the later ones making only 10 hp less and 5 lb ft. .. The HD LQ4 was only rated at 4400 rpm instead of 5200 like everything else... plus have power enrichment delay neutering them even further. I own both and wouldn't honestly pay more to buy an LQ9 when looking for an engine...

 

Lol yeah...my LQ4 is all stock, but I definitely removed the power enrichment delay... Also able to remove the AFR spark adder as a result, which allows for less jackassery in the timing table.

 

Ok. So it has been stated that the LQ4 has a shitty timing curve. Well what does a good one look like? Can you just plot in the curve from another car/truck? Do you just add X degrees to fix that?