Hi Trev, thanks for your report.

My report : Bench Dyno test of a STOCK LS-2 with my ITB's AND my ECU-882C.
This test showed MORE Torque over 2000 RPM when compared to the stock intake and 502 HP at 6200 RPM.

The TPS is a CTS stock GM style POT.

Common air chamber/balance Idle Air with 5/8" bore between runners. (3/8" port window)
Provision for Dry NOS bosses cast into runner bases.

The .080" thick Brass Butterflies (beveled) fit the machined bores perfectly as the floating shaft slot is wider than the butterfly.
The throttle shaft rides on 8mm Ball Bearings. (sealed bearings 2RS)
They both seal well to allow a 400 RPM Idle Speed with a BIG camshaft.

YES, the throttle shafts are perpendicular to the crankshaft (thanks for that observation) with that arrangement allowing for a very quick and easy "sync".
An air balance channel (5/8" bore) is cast into the intake for good MAP and IAC flow.

Lance

 

Did you ever compare different bore diameters?
Curious why you went to the extensive effort of developing your own itb's?
Do you examine and reject the Jenvey stuff? I wish they were available 11 years ago when I found my cross ram setup out of Australia.

 

Also..do you have any pics from the top with the filters off?
My cross ram with 4" tapered bolt on inlet trumpets give about an 14" runner length

 

Hi TFM, yes but ONLY in my EAP engine model application.
Then I asked Ron Shaver with his answer as "the larger the better".
My runners are tapered on both sides of the butterfly bore with a 4" inlet Bell Mouth.
The manifold length is 9", good for a 7K RPM torque peak with the correct exhaust pipe length.
The manifold is "offset" from the port center line, done to ENHANCE the designed in head swirl which is also good for fast combustion.

I work with the Redline Weber division of Worldpac, the largest provider of ITB's.
I use Solid Works and own a Rapid Prototype Printer.
I have a good pattern maker.
I have good foundries in the LA area.
I have made my own castings for thirty+ years.

As for the Jenvey ITB : At the time I cast my LS-Stack Injector (15 years ago) they did NOT even know a GM LS existed.

I have many pictures even single ITB's casting pictures.
I have a Oil Pan for LS-x, Valve Covers.

What would you like to see ?

Lance

 

This is what I run..well a modified version.
I Originally bought my setup from an outfit called hocking racing back in 05...who ran a car in the v8 super car series years ago. I understand they may have sold the molds/jigs design rights to DC&O.

I've cleaned up the internal passages, recut blades, fitted a progressive cam pivot linkage, added direct port N20 nozzles....port matched to my tea ported tfs heads with hollow int. valves, BT dual springs, 3/8 mantons, yella terra roller rockers..custom eps cam...(big duration, .6xx lift) hand notched pistons...

It is definitely not the best manifold design...but it clears the hood on my e36 conversion👌

This is backed with a close ratio T56 (ZR1 ratios) with internal pump and external cooler, CF dshaft, built 210mm LSD with road racing clutch pack setup, custom ramp angles, diff cooler.

In the process of designing and having made a very custom 1.75-1.875 stepped 4-2-1 headers with bank crossovers (180 degree headers) with dual 3" oval exhaust pipes, crossover, and a custom large single muffler with external dead end chambers and dual Center exit tips....should sound like a proper Judd V8 knockoff ..albeit at somewhat lower rpms...

Cheers from up north...

Trev
...

http://stackinjection.com.au/main-gr...cross-ram.html

 

Hi Tevor, I can use EAP (Engine Model PC Program) to predict the Torque/HP output of your engine.
There are objects that allow "step" headers. (3)

I would need your engine specifications.
There is no cost, a free offer ?

Lance

 

Well that is a very generous offer!...however with the new exhaust..the primary length will be determined by the 2 crossover pipes. Then we'll match up the others to suit. Are you suggesting that the software could predict the ideal first step length? I imagine I can make the first 1 3/4" section any length that is ideal. It is the second 1 7/8 length that will be quite long. (4-2-1).

What information/specs specifically would you need?
If you can you bullet point them...I'll respond with what I know...

Trev

Trev

 

Hi Trev, your data is clear with some guesses. (260/272 .631" 110 C/L and 12.5 CR.)

NOW my exhaust : 4-1 with THREE steps (6-8-30) 1 3/4, 1 7/8, 2.
CROSS #5 & #8 as they are BOTH 90*.
This is a report of 582 Torque@5500 (VOL=126) and 662 HP @ 7000 (VOL 111)

I have constructed 180's for Ford GT's, Pantera Group IV, Bizzarrini, and other race cars.
As for the muffler, I made my Lola 332 "single" out or Fiber Metal (inside tube) a "rem" from the B-2 muffler program.

Please correct my facts, cam & port flow numbers ?

You asked for casting pictures : Attached

Lance

 

Wow some neat looking design details...Definitely looks like they are designed to perform!

Anyways my 6.0L LS2 sits as follows:

• Cathedral port port matched cross ram 50MM ITB's - with ~15-16" valve to
airhorn lip distance - continuously tapered runner to a 3.5" radiused 4" tall trumpet/horn
• 43lb/hr injectors

So Patrick G. Spec'd out my cam based on my old 4-1 exhaust, stepped primaries at 11" - however that was 1 5/8 - then 22" of 1 3/4 to 3" collectors, 3" xpipe and dual 2.5" tailpipes.

(new exhaust will be some form of stepped 4-2-1 with 180 degree crossovers, crossed over dual 3" exh. I would say 1.75 - 1.875 to whatever collector diameter my fabricator can fit (long length taper cones). The first length can be any distance out, while the second length will be determined by however long the shortest crossover path can be...)

My current cam was spec'd as:

"eps custom cam" (eps) EHI/LXL lobes 110 LSA + 1 advance 239/242, .638"/.615")
can't find my original cam card at this moment for more...

• trick flow 225 cathedral port heads. tea cnc ported with hand finished bowls
• flat milled .015
• 62.5cc chambers after mill (65cc original)
• pistons .007" out of the holes
• FYI..static compression would have been 11.6:1 with an .045 gasket...I used .045" + the hand cut valve notches...approx .11" deep reliefs???
• 2.055 hollow stem intake valves
• 1.57 exh
• dual springs by brian tooley, good for .660 lift
• ti retainers
• Trickflow mls .045 headgaskets
• ARP Head bolts
• Hand notched stock LS2 piston reliefs
Flow #'s for TEA modified heads
Flow Figures (I/E): (from TEA website -* Tests conducted at 28" of water, 4.030" bore, 1.875" exh. pipe)
.100: 70.8 / 61.3
.200: 144.3 / 120.4
.300: 222.2 / 187
.400: 279.3 / 232.6
.500: 315.8 / 260.1
.550: 328.6 / 267.7
.600: 335.6 / 274

• Lunati reduced travel linkbar lifters
• 3/8" BT Racing Pushrods
• YT 1.7 Roller rockers
• Katech rod bolts
• Katech Timing Chain, Cloyes adjustable Gears
• Hi flow oil pump
• Improved racing pan baffle
• Alloy Flywheel
• 10% underdriven Superdamper
• ZR gear ratio Tranzilla T56 Magnum
• CF 3" dshaft
• 3.64 rear gear
• 24.7" rear tire

 

Hi Trev, your data/my exhaust : 5000 RPM 574 Torque @ 117 VOL / 6500 RPM 690 HP @ 122 VOL.

My Exhaust : 6-8-20 with same pipe diameters as I stated above. (OA is 34")

Lance

 

So I am wondering what to make of this information...

I am planning a 4-2-1 exhaust...So are you implying that I might try putting my 2 primary steps at 6-8" out..or at 20" out from the heads?

I'll be starting with 1.75" and then stepping to 1 7/8" before the 2-1 collectors when each will then likely exit into 2 or 2.25" before the final collector where they will exit into a 3" exhaust.

My guess is that after the relatively short 1 3/4" section, I will likely have a pretty long 1 7/8" section (not yet defined...but potentially up to 26") as I need to do a 180 degree crossover. The next 2-1 section might end up fairly short...but could also be as long as needed.

Any changes you might also suggest to the engine combo? Does my camshaft need to be optimized again? My goals are still great peak HP with as wide a powerband as possible for road race style use. I wasn't chasing ultimate peak hp.

To keep in mind..I also have a programmable N20 set-up that will be jetted for 100.. but can be jetted for up to 300whp..so I need to keep that in mind with the camshaft.
The N20 system has its own separate standalone fuel system (race fuel) and computer with all safeties (fuel pressure, N20 pressure, wideband, TPS, RPM inputs).

I was going to run the 200 or 300 N20 set-up at a top speed event in top gear only. My close ratio ZR1 gearbox ratios to max out 6th at ~205ish mph.

 

Hi Jake, I did an EAP Model, a Back/Back LS-7(100mm)/my ITB 65mm DD using the specification provided in your build statement (Pontiacolypse).
The results were 806 HP @ 6500/757 HP @ 6000 for the LS-7 intake.

YOUR VOL is 120 @ 5500

There are two items I guessed about, the exhaust runner length of 32" AND Port Flow numbers though I used my best record of that flow. (LS-7 head)

A 30" primary increased power to 811, same RPM

Lance

 

Where is Jake's post?

 

Wrong thread I think but fantastic information. That's better than I expected. I am assuming in this case we are talking bhp.

The 32" primaries is correct. Thoughts on how a tri-y would do vs standard 4:1?

 

Hi All, this is another one of my ITB installs.

Lance

 

Lance, kind of off topic, but I thought you'd like to see this. After scaling the tune, I am seeing 601 g/sec airflow, which I'm calculating out to 802 BHP. The injectors are 98.4% duty cycle and 51-lb injectors (at 58psi), which calculates out to 801 HP. Even more impressive, at 5600 rpm, I'm at 120.2 VE. Your model is pretty spot on.

 

I know this is mostly focused on ITB's, but since it's been bumped up I am interested as to how the MAP reading in KPA compares to power. I am doing some low tech testing of air lids on my car to see if there is really much of a difference. Using an eBay OBDII bluetooth adaptor and the torque android app I can data log my MAP readings vs throttle position, RPM, speed, etc. My baseline MAP reading is around 98KPA (~670' elevation). My initial testing shows air lid 1 produced 98 and 99 KPA for a short time, and lid 2 showed 97 KPA. I still need to do some better testing such as a standing start 1st-4th gear pull to see if the "ram air" is helping, and I would like to validate the results on a Dyno and at the drag strip.

So that was a long way of asking is there a way to compare HP lost/gained with a difference 1-2 KPA in the intake manifold? Is there more to it than just the KPA reading at WOT (would the larger outlet/volume lid perform better at part throttle for example)? My car is H/C/I with a fast 102 and NW 102 TB for reference.