I realize that the ls3 is a slightly larger displacement motor,but what are the real differances in them? What is it that they have that makes 30 more hp stock? heads and intake? Longer stroke? Just curious...they seems to make real good power when modded.

 

Heads, intake manifold, a larger bore of 103mm compared to 101mm. The stroke remained the same at 92mm. The PCM calibration is also different.

 

I have read that the majority of the difference comes from head design. Just look at most LS@ guys who mod - many go with LS3 heads and pick up descent Hp.

 

You pick up 20HP on the LS2 if you install LS3 heads. The rest is displacement.

The tune isnt better on the LS3, its optimized to use 8 more degrees timing between 3 and 4k RPMs where the LS3 heads are inefficient. You wouldnt make more power using an LS3 tune on an LS2.

Trick Flow 225s on the LS2 make 520-530rwhp where the LS3 cam only makes about 500rwhp with the same cam. Trick Flow 235s on the LS3 would be the same 15rwhp higher at 535-540rwhp. Its just a better head but people keep trying to port the LS3 head instead of taking the cue from the LS2 cars that make more power. Tuners makes more money porting the LS3 castings for you where Trick Flow gets it if you go with the better head.

 

Spin, safe to assume you're talking about the CNC ported version of the Trickflows? I think heads will be my next major mod and it would be killer to grab 530+ at the tire.

 

Is this a direct bolt on (intake and heads) or is it more involved?

 

You don't think the intake helps a lot as well?

The LS2 picks up LOADS of power going to the FAST 102 while the LS3 picks up very little.

 

Everything I have seen ON THIS FORUM, no real-world aftermarket parts/tuning experience.
The LS3 is superior to the LS2 in stock form. Once you mod, the LS2 catches up and they are about even. I think this is due to intake/exhaust restriction on the LS2. (heads are a big part of this.) The above answered the technical questions.

 

What makes the 235 trickflows better than the 225s?

 

Heads are easy to swap, if you're decent with the wrench and take your time doing it (approx 8hrs for a first timer going slow). Intake Manifold can be done in about 1hr for a first timer. Tuning afterwards are for the pros that know what they're doing. And those are hard to find.

 

what do ls2 heads flow? what do LS3 heads flow? power is made in the heads.. how about the cam? what are the specs on both.. and the intake.. an engine is an air pump so move more air and you make more power

 

Max effort LS2 vs max effort LS3, they make with in 5. Ill post a graph for all to see.

 

It seems like 20hp on an LS2 is common. Thats alot of hp for just an intake swap.

 

So if what others are saying about the fast is fact, then that would seem the way to go. 20hp just by swapping intake vs swapping heads and intake.

 

Probably far more detailed info than most people are willing to read or absorb, but here it is anyway.

http://corvetteactioncenter.com/spec...ls3_page1.html

 

Most cammed LS2s at 430-435 with a ported FAST make in that 455-460 range. With a LS3 head (unported) + the LS3 FAST is about 475-480rw. Trick Flow 225s are 520rw with a FAST.

.....Until someone tries a Trick Flow 235 on the LS3. I have many PMs from owners of the AFR 230 who werent happy with the results while we have seen near 530rwhp with the TF 225. Until H/C LS3s use some other heads we dont have a lot of data on how the competition stacks up against AFR or ported LS3 heads. So far we see the 1/4 mile challenge owned by trick flow on the LS2. Why no one thinks the LS3 w/TFs would be just as good a performer is beyond me.

I just tuned ADV Induction's ported heads on a 416 and it didnt even match box stock LS3 head numbers. Porting LS3 heads isnt the way to go. I will be retuning that same car with stock LS3 heads in a few weeks so we will see the exact same car with only the head swap for data.

Thanks for making data available.

While everything you say is true, flow numbers without a velocity spec is not an indicator of power made. There are countless ported LS2 heads that flowed 340cfm (Old-MTI stage 3 garbage) and none made any power on those hogged out intake runners. Aintqik and I had seen MTI's heads make 460rw on his 403 stroker and only a head swap to ETP 215s (flow less) picked up 40rwhp. The AFR 205 flowed 305cfm from a tiny 205cc runner and hit 500rwhp on an LS2 with a 236 cam. The LS3 heads flow 330cfm out of the box but its from a 260cc runner and its a low velocity but I've never seen 500rwhp on an LS2 with them.

Porting it does nothiing but slow it down more. A Trick Flow 235 stomps that from a much smaller runner. So if two heads flow the same, the smaller runner size makes more power.

The 4" bore limits the size head from Trick flow that you can use. The Trick Flow 225 is for a 4" bore and a 235 needs to be on a 4.03" bore or bigger.

There has never been an LS3 with a Trick Flow 235 used so to say modded they are even isnt true. I dont buy for a second that ported LS3 castings are anywhere near a CNC Trick Flow. The LS2 with trick flows own the 1/4 mile challenge so its too soon to make a statement that they are even when modded.

The Stock FASTs are 12-15 for the LS2 version and 7 for the LS3 version.

Direct Bolt on.

Yes, the Trick Flow 225 sits on the fastest LS2s. If you have the LS3, the TF235 is your head.

I've put it out there before: I will install for FREE Trick Flow 235s on a H/C LS3 and dyno it on 2 local dynojets. The cam must be the G6X3.

 

Damn Spin--I don't have the LG cam but I feel like the TF 235s will be my next major mod.
If you don't mind, what is the reason for requiring the G6 cam? For comparison's sake to an already existing chart/graph you have?

 

AFR 230's are WAY to big for a stock displacement LS2 or LS3. Done back to back before on 402 engines with the G6X3 and I have made more with the smaller heads on it, not only HP but TQ as well.

 

I don't know about that. 12rwhp for a FAST intake? I don't think I've ever seen an LS2 show so little with one.

 

I might have seen 12-18 PEAK hp on my stock LS2, they generally carry more HP than that though under the curve...I haven't seen anything as high as 7 hp on a LS3 version though...