Hello, I have a 2005 base LS2. I’m about to place an order for Kooks 1 7/8 w/ 3” Catless X Pipe to go with my corsa axle back. Also a Vararam intake.
I’m curious on the dyno with the tune what I can expect in gains to the wheels. Thank you

 

If your in Cali I’d second think that.
but maybe 390-400.

 

I’m in canada. So 390-400 to wheels? What kind of gain to wheels is that?

 

Manual or Auto??

Stock numbers are around 340rwhp for manual and 320 for auto.

I would think you would be around 370-390 ish rwhp with those mods (Auto-Manual)

Just a guess mind you

 

IMHO, a good "hands on" tune (not a mail order tune)by a reputable Corvette specialist should gain 10-15 rwhp over stock. Adding the headers, x-pipe & intake should get another 10-15, so conservatively 20-30 rwhp all told, depending up[on how aggressive the tuner wants to be.

 

There is dynojet tune, and then there is street tune,

completely different ideology.
Dynojet roller tune can show peak potential output when the engine is pushed near edge of fuel/timing in a specific gear ratio with specific ambient conditions and exact (roller mass) load which does not accurately resemble real world loading and especially higher or lower gears.

A street tune is a general setting with reduced power which can make the engine reliable and consistent behavior as conditions such as load and temperature wander and fuel quality varies naturally pump to pump.

Many tuners do not understand the difference. Furthermore there are other types of dynos than dynojet which further impact the load and rate of change variable from which ideal timing is derived in particular gear ratio.

My advice
1. Find a tuner who specifically prefers to use a dynojet and has tuned hundreds of vehicles on dynojet, they will be familiar with dynojet load
2. Have a discussion about minimum best timing, find a tuner who understands they will reduce the timing to a minimum value for reduced cylinder pressure in street config

Understand that:
The tune which yields highest output on a particular dyno will generally not be safe to use consistently in the vehicle for all street conditions and varying fuel quality. This type of tune will typically score rod bearings over time due to occasional spike of peak pressure near TDC. You won't find out until the engine develops a rod knock maybe 30k to 50k miles down the road.
Your question 'what possible gains' is a kind of misnomer, you can't "see" the true gains from a dyno, the dyno is merely a tuning TOOL. It can show you gains for before/after but these do not or should not translate to real world conditions where too many variables throw the 'perfect dyno tune' into dangerous territory.
No you cannot depend on knock sensors, don't even go there. Knock sensors are not reliable and they should never be used to tune an engine, ever.

To see true gains, especially for street tune in a vehicle, it must race at the track, to find true gains generally in the form of MPH for example.

I recommend:
I've tuned hundreds of vehicles and this is my general advice.
1. You must have a wideband in a performance vehicle
2. Install your basic external engine mods and then use the wideband to determine if the a/f ratio is adequate.
It should be
3. If A/F is adequate avoid re-tuning the engine unless you can find someone who meets the criterion I suggested, "minimum best timing" and "dynojet only".

More information
There are three primary ways to change significant power when re-tuning a basic engine config. These are: Fuel, Spark, Injection angle.
Depending on your engine's intake design it may be possible to see +30rwhp just from injection angle alone. Some have seen +100hp on a forced inducted application before.
Fuel: If the a/f is proper then there is nothing to do there.
Spark: The factory timing may be adequate, or it may be too far advanced. It is rarely under-timed. This is why I suggest not re-tuning the engine at all: Your's will likely have at least too much timing already, and many tuners assume they need to add timing to the baseline for power increases to customer satisfaction. Few tuners will actually remove timing from the baseline. This is a dangerous assumption and unfortunately quite common.
Therefore, if you see good wideband a/f ratio (naturally aspirated 93 octane a/f ratio shall be say 11.8 to 12.2:1 at wide open throttle for compression 9:1 to 10.5:1 engines made after 02+ for Chevrolet). I would leave it alone.

 

Those stock number seem low my c5 98 with no mods was 317 hp at the wheels

 

Auto or manual? I think the numbers provided by the other posters are real close for an Auto. I had an LS3 auto tuned on a dynojet with the same mods you are proposing and it went 404hp/399tq at the wheels in the Texas heat.

 

He has an LS2 though.....

My 2000 Z28 with long tubes and tune went 350ish RWHP....... I would figure the numbers I posted would be close and conservative.

 

 

Don’t expect anything, you have to do it more air in, more air out =tune, no expectation no hurt feelings, but pick your tuner wisely, LS2 you want 1 3/4 headers, no your buddies not right.

 

no it didn’t

 

Typical gains on an LS2 with header, intake then dyno tune are 20 to 25 wheel hp/tq.

As an example, I used to have a 2006 Pontiac GTO with the LS2 (4-speed auto). I had installed a small Cam Motion cam and an intake but was still on the stock manifolds. Car made 380 wheel HP on a DynoJet. I installed 1 7/8 Kooks headers with cats and an X-pipe and went back to the exact same tuner two weeks later. Time of day and temp were nearly identical also. Made exactly 400 wheel HP which was my goal.

Ignore everything from Kintal0n, also.

 

With a tune/headers/X pipe, would gain you maybe 25hp depending on the dyno

 

my 05 LS2 with a vararam CAI and Zo6 mufflers + a dyno tune made 377rwhp. With headers and x pipe I'd expect around ~400rwhp

 

When my 2011 GS (LS3-A6) was bone stock, it made 371 RWHP on the dyno ... Adding a set of 1 3/4" headers and a dyno tune, it made 405 RWHP ... a gain of 34 RWHP.

Again, that was on an LS3 ... I would expect an LS2 to be at least 20 RWHP below that with just headers and a tune.

 

Lots of opinions here, so far seems to me I’d expect from 20-25 wheel gains… for $5,000+ (CDN) i think that is outrageous and a waste of money. I am starting to think to put that $5000 into the bank and save another 10 sell my LS2 and get a grand sport.. the LS2 has such a bad name, and I wish I would have done research before hand.

 

Says who? The LS2 is pretty much bulletproof, the LS3 is more desirable but nothing wrong with the LS2 at all

 

says a lot of people, not necessarily saying they are right but I hear it a lot more than I hear keep your ls2.. everything from my steering wheel to the rear diff problems to the t56 to the 6.0L , prove me wrong pls I would love to keep my car lol

 

My buddy Marc has cai, headers intake tb and tune-converter and he went 10.7 in 1/4 mile with his LS2 C6 so say what you want about the LS2 but the power is there with the right parts and tune.

OP-you could save another 5k and go FI. That's what I did with my LS2. Stock tb, stock intake, shorty headers, stock cats and corsa out back. 582 at the wheels with my A6-that's the base kit, no meth nothing.