LS7 on the Dyno

[eliot]

davefiddes said:

Basically unless you have the engine set up for high octane US race gas or in the UK on Optimax then it's a complete waste of money to use Optimax in a normally aspirated Chevy. IMHO.

Yep.
I guess the only exception, is if you were running a relatively high N/A compression ratio - I suppose anything over 11:1.

I'm running 7Lbs of boost on a 9.25:1 chevy, which gives an effective compression ratio of 13:1 - I can run that on std unleaded, but I pull my ignition back to around 25, which is very conservative - In fact, now ive got my inlet temps down I could probably put some timing back into it.

[builder]

chuntington101 said:

builder, that thing looks better and better every time i see it! what headers are you planning on running? can't weight for the LS9 (i think) to come out! Chris.

Thanks, Chris. I have not sourced headers yet... Thinking I might try something completely different. LG Motorsports makes some seriously good long-tubes. So does Kook's. Lots of options "off the shelf" for the Vette.

That LS9 is going to be amazing. Yes, that is what it will be called. I don't know if anyone saw the post the other day about the first LS9 test engines coming off the line, but I was misinformed. The new assembly line was making next year's LS7 for testing. The "9" will be out in 2008...supercharged 427!

[crafty]

Scott,

Off the shelf ones aint gonna fit.

Generally exhausts run low and near the gearbox. Not as low as the dyno headers in your pics, but that is the general idea.

If you're gonna run your exhausts under the axles, any off the shelf LT headers you buy will be way too low..

Bob (LS3 Ultima) and I are checking out some options for headers for our LS2's at present in OZ. I will keep you informed of our progress..

[builder]

crafty said:

Scott, Off the shelf ones aint gonna fit. Generally exhausts run low and near the gearbox. Not as low as the dyno headers in your pics, but that is the general idea. If you're gonna run your exhausts under the axles, any off the shelf LT headers you buy will be way too low.. Bob (LS3 Ultima) and I are checking out some options for headers for our LS2's at present in OZ. I will keep you informed of our progress..

Oh, yes. I know they aint gonna. Not sure exactly what yet. Would definitely appreciate hearing about options. Thanks! Likewise, I will post anything I learn as well...

[G Man]

builder said:

Oh, yes. I know they aint gonna. Not sure exactly what yet. Would definitely appreciate hearing about options. Thanks! Likewise, I will post anything I learn as well...

THe lS7 head was developed by Chapman Racing IIRC, which also supplied the head for my 377ci, just a remote chance the exhaust positioning is the same, Chapman's 18,14 and 12 degree head have the same layout for the exhaust and thus can use the Ultima factory 18degree exhaust - Just a chance

[builder]

Hey GMan,

The exhaust ports on an LSx are not the same distance, side-to-side, as the Chevy small block.

Here's the SBC:



Here's the LSx:

[Boosted Ls1]

And what's really neat is that all of the LSx's share the same bolt pattern for the exhausts so make a set for any one engine and the market's potentially huge

Boosted.

[steve_d]

Here we are on the 4th page of 'LS7 On the dyno' and still no video clip of it running, what's going on?

Steve

[mhussa]

Digressing a little bit I found this on my web travels, thought someone may find it interesting, "rumour" has it there will be two new LSx engines in 2008:

The N/A LS3 approx 450hp and the supercharged LS9 approx 600hp (combined intake/charger setup). Both will be 6.2L (377ci sound familiar? ).

take a look at this link:

www.corvetteconti.com/welcome/index.php?option=com_content&task=view&id=103&Itemid=47

Lets see what the LS7 can do , there ain't no replacement for displacement (apart from shedding weight and blah and blah blah blah).

[builder]

The final run made 564 FWHP! Video and dyno sheet soon. I will have the engine back next week and can start to build an Ultima GTR. Have done some organizing in the shop, but still a long way to go. Still no electricity. Here are a few more pics of the lump on the dyno...manifold spun, T/B up-side-down, T/B spacer to clear block.

[crafty]

Hi Scott,

Excellent work mate!!!!

Hey - does the LS7 come with a cable throttle body or did you fit that?

I had to run a 2002 Camaro (from memory) PCM as that had the cable throttle body.


GC

[builder]

crafty said:

...does the LS7 come with a cable throttle body or did you fit that?

The LS7 comes with a fly-by-wire T/B which I will likely be selling. I am going with the UMI mechanical T/B. The one in the pictures is a F.A.S.T. unit. The UMI makes about 3-4 more HP and deliveres slightly smooter response across the RPM range than the F.A.S.T.

-- Scott

[mhussa]

so it does walk the talk. I'm not going to deny it, I'm very jealous. Good luck with the install.

[davefiddes]

Why aren't you going to keep the fly by wire throttle? Especially in an Ultima with such a long and potentially sticky throttle cable.

[builder]

mhussa said:

so it does walk the talk. I'm not going to deny it, I'm very jealous. Good luck with the install.

Oh, yeah baby!!! Thanks!

davefiddes said:

Why aren't you going to keep the fly by wire throttle?

The ECU I am using won't work with it. Only the GM stock PCM will controll the LS7 electronic T/B (for now). The stock PCM won't operate the LS7 in a "stand-alone" installation wthout the other Corvette electronics. Also, electronics are required at the peddle (TAC Module) which would have to be adapted.

[davefiddes]

davefiddes said:

Only the GM stock PCM will controll the LS7 electronic T/B (for now).

Ah right. I was sure I'd seen the fly-by-wire throttle grafted into an old Camaro in a magazine engine swap article. I guess they took the whole lot including the ECU.

Having had a stuck throttle I can understand not wanting to risk any sort of aftermarket hacked option...

[builder]

davefiddes said:

Ah right. I was sure I'd seen the fly-by-wire throttle grafted into an old Camaro in a magazine engine swap article. I guess they took the whole lot including the ECU. Having had a stuck throttle I can understand not wanting to risk any sort of aftermarket hacked option...

Dave, I remember your post about that. Yes, there are a couple of those Camaro swaps running about. It was probably an LS2. Software is available for that PCM (called LS2Edit). There is one company making a software tunner for the Z06 (HPE), but none (except mine - BigStuff3) that allow for a stand-alone installation.

There is also an air-flow issue with the rotated intake and flipped TB. The mechanical TB returns the blade opening to the normal direction for the LS7 manifold. Otherwise, throttle response and air-flow are not as good...and it makes #6 too lean.

I hope my craftsmanship on the throttle cable and bracket turns out better than any sort of hacked option.

[builder]

Here are some updated photos of the LS7 with some of the changes made. This is a snip of what will evolve into the build site as time allows.

Hope to have the dyno sheet and a video soon...

-- Scott