Ryne @ CMS

iTrader: (10)

maybe i just had the first x-pipe and maybe they fixed it since then. but just had dual 3inch made with magnaflows

Scoggin Dickey

iTrader: (34)

It's on their "punch list"! They said they just need to finish their current project (Ford intake) and then the L76 is next!

Stang's Bane

iTrader: (22)

I spoke to the Fast rep at a Super Chevy show last year and he also said they were working on a LS7 intake, but not to expect huge gains out of it, as the factory piece is so good. He said they were looking at the L76 piece but had not made any decisions at that time. I guess times change huh??

Why can't they work on more than one at a time??

71CamaroLS1

I have to say, that X-pipe does look suspicious. Have you tried dropping out the exhaust and making a dyno run? A serious exhaust restriction would account for high RPM power drop off, as well as the fact that your peak torque numbers are not real high.

Is the cam card in your post the currently installed cam? If not, what are the installed specs?

If it's cam related, the two valve events which control high-rpm extension are, in priority order, Intake valve close and Exhaust valve open. Without access to pressure volume trace data (which you can't get without mega-dollar engine dyno testing), or engine simulation software, I can't say whether your EVO is early enough, but I'd make a wild guess that it is. That leaves moving your IVC later. If you want to leave your overlap the same (for idle and drivability quality), you would increase intake duration, spread the LSA, and retard the intake center line. For instance, 240/248/113+3 (110 ICL), or 244/248/114+2 (112 ICL). This would move IVC later by 4 degrees and 8 degrees, respectively, while leaving overlap constant.

But be aware, there's no free lunch - moving your IVC later will increase reversion and therefore reduce low speed torque a bit. Depending on how you drive and what your goals are, you might find you like your current setup better.

If it were me, I'd be tempted to first drop out that X-pipe, put on ear muffs, and make a dyno pull, to eliminate that as a possibility ...

Patrick G

iTrader: (14)

A 416 with L92 heads needs an intake valve closing point of around 52 degrees ABDC at .050" if you're wanting a power peak above 6100 rpm (while still maintaining good mid-range torque). The cross sectional area and tuned runner length of the L76 intake will force a fairly early power peak without the proper intake valve closing point. Too early of an EVO might also make torque a little soft. It's all a balancing act. 71CamaroLS1 has some outstanding info above.

Ryne @ CMS

iTrader: (10)

this is actually my exact exhaust system i had on my car, they took a picture of it before they put it on

cybernco

Your a real GHL Motorsports pioneer. Cool!!!
I can't wait to hear about your new engine.

Bink

71CamaroLS1 - which Dynomation version would you suggest?

Ryne @ CMS

iTrader: (10)

yep i am, waited 2 days in phoenix in january 06 , sounded great, but restrictive

71CamaroLS1

I've not used the ProTools version - but the base version of Dynomation is already a pretty advanced piece of software, so my guess is unless you're a full-time engine builder/designer you'd probably never get to the features in ProTools.

Be aware - Dynomation requires a lot more input data than tools like DynoSim - you have to have accurate data on things like intake runner/port length, port cross section, runner/port taper, for instance. And it's definitely a garbage in/garbage out kind of deal But for a geek like me, it's pretty addictive to play around with combos and watch the changes in things like pressure/volume traces and intake/exhaust velocities ...

Old SStroker

Here's an interesting comparison of torque/hp curves for a fairly similar combination. Something is very different at the low and high ends of the curves.

It's currently active thread.

https://ls1tech.com/forums/showpost....93&postcount=1

cybernco

Here's his final dyno.
https://ls1tech.com/forums/showpost....&postcount=108
WKMCD is very competant; his advice is always solid.

2c5s

iTrader: (11)

See if you can get your dyno graph in SAE and not STD. What type of dyno was used? How does the car feel? Is it lazy or fast, faster than before? What was the A/F, timing on the runs? Do you have access to any of the scans while on the dyno?

Example, I just had my old 408" on the dyno in another car, clogged cats cost over 40 rwhp and rwt. In addition, the PCM was pulling timing like crazy, max of 16' advance. Your scans will tell the story.

Bink

Hey Thanks for info!
Is there a place where I can access the neccessary data for the LS1/6/7 ??

71CamaroLS1

I've never tried to find any data on these motors ... but I'm about to try, since I'm planning a 427 short/LS7 head build with carb-style intake for a '69 Camaro project, and there is very little info available for camming that combo. Even with the plastic intake LS7, the aftermarket tuners seem to be all over the map as to what works best - or to put it more specifically, they seem to get fairly similar results with wildly different grinds, e.g. Katech torquer 220/244/110 and LG G7X3 228/240/118.

Bink

That's pretty much where I'm heading Katech 427 short and LS7 heads (if I ever get this office project under control ) - except with the LS7 intake.
Plus, I'd enjoy the learning experience .

Now to buy the Dynomation.

cybernco

The engine almost dies from idle, then comes to life with loads of torque. I'l PM you with the specifics.

71CamaroLS1

The more combos I read about using the L76/L92 combo, the more it appears that the L76 is limiting peak RPM, either through runner length or lack of runner volume or both (it does restrict airflow some as well, but that doesn't account for why so many different cam/cid combos all peak out by about 6100 - 6300).

Here is further evidence:

http://www.tpis.com/plog/index.php?o...Id=29&blogId=1

However, designing an intake to overcome the L76 limitations will be tricky. The L76 design clearly "crutches" the big L92 intake port by using finite amplitude wave tuning to augment torque. The alternative intakes I've seen so far - the sheetmetal intakes and the Livernois carb intake - all lose quite a bit of mid-range torque in order to gain on the top end. It will probably take Wilson and FAST collaborating again to design a minimal compromises intake ...

SS Blazer 07

TPI Specialties has a new intake for the L92 & LS7 with cnc ported runner & high flow fuel rails. A bit pricey with s list price of $2400.00 with injectors & fuel rails all aluminum. www.tpis.com custom fab type unit. They say it clears the hood & straight bolt-on. LOL
http://www.tpis.com/plog/index.php?o...Id=28&blogId=1

Fuknmovin

iTrader: (1)

As a exhaust fab guy, I would have to say that X is not the right way to do it. The X pipe config. is one of a balance tube or port NOT a transfer from side to side, by doing this they are actually reducing the size of the system in the middle of the X. Look at how some others do it like Borla, their X is done properly, the hole between the two sweeps in the X or the merge point should only be 50ish percent of the tube size to get it proper, any more or less does not seem to work well, I have seen this and also learned it from an EXPERT exhaust guy, John @ Hi-Tech exhaust, that man builds some MONSTEROUS power building systems and headers. I saw his headers in a back to back test on the same day same dyno make 80ftlbs. more than a 1 7/8" Hooker Super comp header on a 434" LSX engine! Just my $.02

-Bryan