Whats Next?

[LGAFF]

Siamesed Intake and Plenum;

441rwhp and Torque
373 ftlbs

Enlarged Plenum(+80ci) with Siamesed Runners:

426 RWHP
361 ftlbs


Any thoughts?

36MM all the way through

siamesed stock intake with Siamesed 1" at top and bottom of runners?

Buy a LS7?

[XfireZ51]

LSx block w Mercury Marine DOHC heads.

[Kevin]

that's....not at all what I expected. Time marches on, guess it's time to upgrade

[Tyler Townsley]

Siamesed Intake and Plenum;

441rwhp and Torque
373 ftlbs

Enlarged Plenum(+80ci) with Siamesed Runners:

426 RWHP
361 ftlbs


Any thoughts?

36MM all the way through

siamesed stock intake with Siamesed 1" at top and bottom of runners?

Buy a LS7?

385 ci crank. 520+ rwhp

[KILLSHOTS]

I hear a siamesed intake and plenum is good for 15HP!

Sorry...too soon?

[Kevin]

385 ci crank. 520+ rwhp

and the cost of the build would almost be as much as a z06

[LGAFF]

I just picked up 2 LA sleeves for $80 :handshak:

[LGAFF]

My wife told me what the next project is....finish the 91 368 in the garage and get it the hell out of here :)

[mike100]

more cubic inches or a different cam profile? Perhaps a different header design... Is there a specific rpm range where the torque becomes less on the before and after tests?

[FU]

Whats Next?

Use the LT5 for a boat anchor.
Install a LS engine and enjoy.

[Tony Davila]

Whats Next?

Use the LT5 for a boat anchor.
Install a LS engine and enjoy.
I'm with him. I love the old LT5 but if you want more power an LS3/LS7 with a bolt on supercharger is the way to go. IF you can handle removing that gorgeous engine from the bay. Or you just except what you have and chrome the crap out of it.:-D

I'm going about the chrome route for now.

[batchman]

Any thoughts?

How about ITBs (plenum = Earth)?

I dunno,
- Jeff

[RussMcB]

How about ITBs (plenum = Earth)?

I dunno,
- JeffOooh. That would be pretty.

[Billy Mild]

Why not FI?

[USAFPILOT]

I hear a siamesed intake and plenum is good for 15HP!

Sorry...too soon?

yeah, put it back how it was.

[Bearly Flying]

Great experiment Lee.

Altho peak power was down, were there any gains down lower in the curve?

[XfireZ51]

Guys,

I want to see what the LSx/LTx community can do if they were forced to use
the stock cylinder heads, albeit ported, for all manner of mods and regardless of displacement.

[KILLSHOTS]

Guys,

I want to see what the LSx/LTx community can do if they were forced to use
the stock cylinder heads, albeit ported, for all manner of mods and regardless of displacement.
The Z06 produces 650 SAE net BHP, and I'm pretty sure it has stock heads.

[Paul Workman]

The Z06 produces 650 SAE net BHP, and I'm pretty sure it has stock heads.

...AND a supercharger too (if nothing else...)

I share some of Dom's sentiment: An LSx with MM DOHC heads... Would like to see some numbers!

[XfireZ51]

The Z06 produces 650 SAE net BHP, and I'm pretty sure it has stock heads.


Let's see if it does that sans SC and using a 5.7L displacement while idling at 850rpm. That's really my point.

[KILLSHOTS]

Let's see if it does that sans SC and using a 5.7L displacement while idling at 850rpm. That's really my point.
I feel like we're really hijacking Lee's thread here, but...

An LT1, without forced induction and with the stock cam but with head porting, aftermarket intake manifold and TB, catless headers and x-pipe, as well as computer and fueling mods, can definitely achieve similar numbers. In fact, with a meager investment of about $1000 in a Borla X-pipe, a flex-fuel kit and a tune and a tank of E85, an LT1 can easily exceed 500 crank HP. I was just reading last night about a similarly-modded Stingray on drag slicks dropping into the 10s.

[Billy Mild]

FI is the only way to go for big power.

[LGAFF]

I am interested in the ITB setup....doing some research. I called Kinsler awhile back and they said $3-10K for an intake.

[GOLDCYLON]

Well for me its a 2009 and up ZR1. Thats whats next or a CTSV for me Lee

[USAFPILOT]

It would be something to see an LS9 blower on an LT5.

[LGAFF]

Great experiment Lee.

Altho peak power was down, were there any gains down lower in the curve?


The dyno started at 3400....but power was down across the board

[Paul Workman]

I feel like we're really hijacking Lee's thread here, but...

An LT1, without forced induction and with the stock cam but with head porting, aftermarket intake manifold and TB, catless headers and x-pipe, as well as computer and fueling mods, can definitely achieve similar numbers. In fact, with a meager investment of about $1000 in a Borla X-pipe, a flex-fuel kit and a tune and a tank of E85, an LT1 can easily exceed 500 crank HP.

Yeah-but!! Ya forgot to mention purchasing the LT1 initially (might add a few $$), ADD to that the computer and wire harness, interfacing it (?) with the CCM, etc., swapping it with the LT5, AND then whatever mods to then get the LT1 to 500+ NA...stuff like that.:o

Review & Re-focusing:


The "state-of-the-art" for a street-driven, stock-bottom/cammed LT5 is (already) 510+ chp
Cammed but still streetable the 350 cid LT5 is about 557 chp (Pete's example)
The single runner, cammed Phase-II 350 cid LT5 made approx. 550 chp
540 chp is readily available w/ stock cammed LT5s sporting 368 cid (10 cid less than that LT1 example)


An improvement over these (above) established benchmarks would have to be approx 10%+ in order to clearly put the results above questions arising from test-related variances. In that regard, (as I see it) Lee's experiment started out in the hole, relative to currently established benchmarks (above).

ITB, split plenum, or some other established NA approach may yield that 10% NA improvement (from air induction only) are possibilities with results yet to be seen(?).

The elephant(s) in the room is forced induction - above displacement. Not dismissing displacement or the chance for eking out a few more ponies from NA, but what interests me is exploring a "cost efficient" blueprint to a SC for the LT5.

I was just reading last night about a similarly-modded Stingray on drag slicks dropping into the 10s.

And, (with all due respect) far as time-slip comparisons go; comparing different cars, different weights and weight distribution, different displacement, different gearing, etc, in attempt to make a comparison between the new LT1 and LT5 all combine to (as statisticians say) "increase the % of ambiguity to the point of irrelevance" (at least as far as this tread goes).

:cheers:

[KILLSHOTS]

Yeah-but!! Ya forgot to mention purchasing the LT1 initially (might add a few $$), ADD to that the computer and wire harness, interfacing it (?) with the CCM, etc., swapping it with the LT5, AND then whatever mods to then get the LT1 to 500+ NA...stuff like that.:o

Review & Re-focusing:


The "state-of-the-art" for a street-driven, stock-bottom/cammed LT5 is (already) 510+ chp
Cammed but still streetable the 350 cid LT5 is about 557 chp (Pete's example)
The single runner, cammed Phase-II 350 cid LT5 made approx. 550 chp
540 chp is readily available w/ stock cammed LT5s sporting 368 cid (10 cid less than that LT1 example)


An improvement over these (above) established benchmarks would have to be approx 10%+ in order to clearly put the results above questions arising from test-related variances. In that regard, (as I see it) Lee's experiment started out in the hole, relative to currently established benchmarks (above).

ITB, split plenum, or some other established NA approach may yield that 10% NA improvement (from air induction only) are possibilities with results yet to be seen(?).

The elephant(s) in the room is forced induction - above displacement. Not dismissing displacement or the chance for eking out a few more ponies from NA, but what interests me is exploring a "cost efficient" blueprint to a SC for the LT5.



And, (with all due respect) far as time-slip comparisons go; comparing different cars, different weights and weight distribution, different displacement, different gearing, etc, in attempt to make a comparison between the new LT1 and LT5 all combine to (as statisticians say) "increase the % of ambiguity to the point of irrelevance" (at least as far as this tread goes).

:cheers:
I wasn't attempting any comparisons whatsoever. Even though I've moved on from my Z, I have a soft spot for the LT5 and always will. Comparing a C4 ZR-1 to a new Stingray is the epitome of "apples and oranges".

If you truly want to refocus, then please try re-reading my statements vis-a-vis post #17...

Dom suggested that the LS/LT guys try making big power with stock heads. I pointed out that the Z06 has stock heads. Only THEN was the Z06’s supercharger brought up. So I responded with examples of easy big power without superchargers. I did not – and my intent was certainly not to – compare the LT5 to LT1/LT4 engines. Further, this thread is about Lee’s cool experiment with an open plenum, not about what current gen LT engines can do with 25-year newer tech and cheaper parts.

[Paul Workman]

I wasn't attempting any comparisons whatsoever. Even though I've moved on from my Z, I have a soft spot for the LT5 and always will. Comparing a C4 ZR-1 to a new Stingray is the epitome of "apples and oranges".

If you truly want to refocus, then please try re-reading my statements vis-a-vis post #17...

Dom suggested that the LS/LT guys try making big power with stock heads. I pointed out that the Z06 has stock heads. Only THEN was the Z06’s supercharger brought up. So I responded with examples of easy big power without superchargers. I did not – and my intent was certainly not to – compare the LT5 to LT1/LT4 engines. Further, this thread is about Lee’s cool experiment with an open plenum, not about what current gen LT engines can do with 25-year newer tech and cheaper parts.

No offense intended; really not taking issue at all. As it happens, whenever the LT5 modifications/performance topic comes up, virtues of the current GM motors comes up as predictably as sunrise w/o acknowledging the "apples to oranges" aspect of the comparisons.

By "refocus", I meant to examine the scenario at hand; that is, the 5.7L LT5 platform modifications/results, specifically to the exclusion of other platforms to limit contaminating the discussion.

As far as Dominic's post goes, I don't know for sure, but "reading between the lines" I suspect Dom may have been endeavoring to expand the LSx performance characteristics comparisons to include the near idle or low speed drivability comparisons accompanying the performance spectrum ; i.e., smooth or near smooth idle (would be my guess). For example:

Likely as not, when id comes to performance mods, driveability (especially at idle or stop and go traffic) gets the short shrift; some even go so far as to say, "who cares if it idles rough as long as (speed/power) is achieved?"

Well, perhaps that's all that matters to some. But, to others, myself included, a rough-idling, over-heating in traffic, often stalling beast with high stall rpm converters, or no off-idle torque...is no fun to drive: been there, done that!

So, another way of evaluating performance is to include drivability (stock or at least nearly stock smooth idle and manners in traffic with the AC turned on and meeting emissions criteria ; "Having your cake and eating it too!" in other words). When you do that, a lot of motors (big cammed especially) go out the window. But, this is where the DOHC shines! (I think is at the core).

[Kevin]

having finally driven a c6z06 I have to say that the car is worlds better then the zr-1, as it should be for being so much newer, but the power delivery FELT almost identical.

[XfireZ51]

We should probably let Lee have his thread back. Maybe start a new one. Paul is correctly characterizing my discussion. It really goes back to breathing more lift/duration or more valves. I feel that a OHV motor is optimized for a particular region of the rpm band whereas an OHC 4 valve has great breathing ability without as much of a sacrifice to reasonable part throttle and idling characteristics. When it comes to all out performance, it's clear GM has decided on the in block cam config and for a lot of very good reasons like packaging, weight, center of gravity, simplicity, hood line, etc, etc. and w the engine management capability of today's processors, the LS/LT motors can really be made to perform and behave all at the same time.
Commenting on the cylinder head, my point was really about how capable the LT-5 heads are given they were designed for a 5.7ish L motor and yet can be found supporting motors of nearly 26% more displacement. In addition, it's all we've got, there ain't no more. no AFR, no TrickFlow, no Brodix, no nuthin'.
Not to mention crank and cams. It's all on us here. Nobody out there helping us out. Just like Lee here doing it pretty much on his own, his own time, his own money. That's why I admire the LT-5.

[Bearly Flying]

"Well, perhaps that's all that matters to some. But, to others, myself included, a rough-idling, over-heating in traffic, often stalling beast with high stall rpm converters, or no off-idle torque...is no fun to drive: been there, done that! "


So have I, trip to B.C. last year, car was stumbling, flooding. Stop and Go traffic was a killer. Turned out to be O2 sensors, but that trip was a nightmare.


Lee's experiment was good, altho the results weren't what was expected, it may provide some insight to the next step.

[LGAFF]

Going back to the dyno soon:cheers:

[batchman]

But, to others, myself included, a rough-idling, over-heating in traffic, often stalling beast with high stall rpm converters, or no off-idle torque...is no fun to drive

I LOL'ed on that one, since I've taken the ZR-1 apart for revision 3 suspension I've been autocrossing friends' "C Prepared" cars. Change "traffic" to "grid" and you've got these cars nailed. Except that for the minute you're driving them - when they are an absolute laugh riot.

And just so you know I'm not poking you Paul, on the street I could not imagine anything of the sort...

Honestly the car reminded me very much of the ZR-1 on a 1st gear parking lot course. I now see why the SCCA rules guys were focused on making sure you could not put an automatic behind a ZR-1 within the rules when I asked them to combine all C4's (so I could use the quick rack).

Later,
- Jeff

[-=Jeff=-]

Whats Next?

Finish the 91 or the Callaway