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Basic run down is 2003 C5 M6 with Mantic MR2 clutch/Tick master
11.25:1 compression 368 inch LS2
CNC Wagner Auto 799 heads w/LS6 valves/Lunati duals
226/232 .605"/.575" @ 114 LS plus 3 degrees advance hydraulic roller
factory lifters/7.4" X .080" push rods
factory LS6 intake with self modded Throttle Body and factory accordian style bellow/air box and K & N air filter
3800 style injectors with street tune
Three Mustang dyno pulls resulted in
408/416
412/409
412.6/412.2
Sure these numbers seem stupid low but the car is strong. I've owned, built, and raced 9,10, and 11 second cars for over thirty years and this thing has a nice flat torque band with crisp acceleration considering the 3.42 gears help it knock down 27-28 miles per gallon freeway
I will post the before and after dyno sheets to document how much if any improvement will come from having my intake manifold converted to a 90mm (4 bolt) LS2 style snout with a TPIS throttle body and some creative air-box mods
I simply do not want a FAST or MSD intake nor a cold air kit
Other than the aftermarket throttle body and headers I wish to have this engine appear otherwise unmolested from factory
STRANGE YES; but this is how I want it
I'm very curious to see if I only pickup 5,7 or 10 rear wheel horse/torque
or perhaps this current setup was holding everything else back big time
It's a true back to back on same dyno within weeks and the same tuner
Predictions, insults, and jokes are welcome as always....
This
And this
To hopefully enhance this
On this vehicle
Last edited by A.R. Shale Targa; 12-01-2016 at 05:45 PM.
I think the engine will gain about 8 rwhp from the LS6 intake getting the 90mm snout & 90 TB.
My 91 RS gained 2 rwhp with the LS6 90 snount & TB, over what the Fast LSXRT 102 & 102 TB made. I think my car's 229 cam in the 383 was just a slightly better parts match for the LS6 90.
I too like the factory look that comes with the LS6 intake over the fast lsxrt. Many people assume its just a stock ls1...you will have some real fun with that.
Last edited by 99 Black Bird T/A; 12-01-2016 at 09:48 PM.
I think the engine will gain about 8 rwhp from the LS6 intake getting the 90mm snout & 90 TB.
My 91 RS gained 2 rwhp with the LS6 90 snount & TB, over what the Fast LSXRT 102 & 102 TB made. I think my car's 229 cam in the 383 was just a slightly better parts match for the LS6 90.
I too like the factory look that comes with the LS6 intake over the fast lsxrt. Many people assume its just a stock ls1...you will have some real fun with that.
Am I reading this correct in that the LS6 intake with 90mm snout made 2 more RWHP than a FAST 102/102? That doesn't seem right to me, especially on a car with a decent sized cam and 383ci. That's where I'd think the 102mm intake would shine.
Am I reading this correct in that the LS6 intake with 90mm snout made 2 more RWHP than a FAST 102/102? That doesn't seem right to me, especially on a car with a decent sized cam and 383ci. That's where I'd think the 102mm intake would shine.
I don't want to get A.R. Shale Targa's thread off topic so I will limit this to one comment.
I mentioned the 2hp gain because the LS6 90 intake works very well in some applications. A.R. Shale Targa may not be leaving much hp on the table using the stock looking LS6 90. Only way to know for sure wuould be a controlled back to back test with the same conditions.
Yes, the LS6 90 beat the 102 LSXRT when tested on my 91 RS.
No one was more shocked than me. I expected a 15hp loss, not a 2hp gain. Stunned might be a better word. I was a true beliver in the 102 LSXRT intake based on theory and everything I had read about it. I'm aware of a case where it made with in 10 hp what a custom fabbed dedicated racing intake made on a very high hp engine.
However, reality of back to back testing proved the LS6 90 the winner over the LSXRT on my RS's combination of parts.
Conditions were same correction factor, air temp with in 3 degrees, same humidity & car's water temp within a few degrees. Both intakes were fine tuned for best result.
My LS6 90 was also ported. My 102 LSXRT isn't ported.
The result was consistent for my car.
I think with a bigger cam and more rpm the LSXRT would have made the most power. Say a 236/244. But with the 15 year old single patterned MMS 229/229 cam thats in my 383, the LS6 90 was better intake based on actual back to back testing on my car and its current configuration. I do think my results are an exception and with most of these newer, bigger, more aggressive cams, that rev higher the fast intakes will give better results in most cases. Maybe even almost all.
Now lets return to the topic of A.R. Shale Targa posted about.
Last edited by 99 Black Bird T/A; 12-02-2016 at 10:40 PM.
The 9 mm snout helps but naturally needs a 90+ mm tb and 85+ mm maf.
The fast and MSD are still superior especially as you add cubic inches
My combo is getting the TPIS 90mm TB and Jackson is prolly gonna bead blast and tumble the black oxide off of it to make it look GM stock Flowing 69% more than the stock 78 will help and I intend to modify my stock airbox for more Flow while appearing GM assembly line normal
I'm not looking to set the world on fire here and I'm positive a FAST 92 or 102 would make more peak power but I'm after a flat as Kansas type torque band and if I can add another 20 pounds of twisting grunt to this combo while appearing unmolested; I will be happy
Obviously there is room for improvement here folks
Intake went under the knife this morning
Last edited by A.R. Shale Targa; 12-03-2016 at 05:31 PM.
So just a quick update on my sneaky project. Or for you Star Wars buffs; "these are not the droids you're looking for"
My esteemed colleague "Jackson" over in Myron Cottrell's TPIS shop decided to one up my "stock appearance" desire by milling off the nameplate and then bead blasting the pretty black anodized throttle body. WOW.
I'm impressed for sure. Here's some pics just prior to shipping
Guess I just figured to "one stop shop". Plus this one has a thinner shaft, blade, and button head screws so it prolly flows even a bit more CFM than a GM90mm
So I opened up the front airbox cover to larger than the 02 Z box opening that I previously pictured. I won't show the pic of custom hackery. Let's just hope function over form on that "free-mod".....
I absolutely understand free mods, but why didn't you just get an '02 airbox cover? Probably because anything and everything for a Corvette costs twice what it would otherwise.
And am I totally missing something here? What is the deal with that 85mm MAF being so popular when everyone specifically favors throttle bodies larger the 85mm? It is not much of a difference on your 90mm TB, but I still see the 85mm MAF used with 102mm throttle bodies and just wonder why more people do not use blade/card style MAF's with these larger throttle bodies. Just curious... definitely not trying to start any ****.
I absolutely understand free mods, but why didn't you just get an '02 airbox cover? Probably because anything and everything for a Corvette costs twice what it would otherwise.
And am I totally missing something here? What is the deal with that 85mm MAF being so popular when everyone specifically favors throttle bodies larger the 85mm? It is not much of a difference on your 90mm TB, but I still see the 85mm MAF used with 102mm throttle bodies and just wonder why more people do not use blade/card style MAF's with these larger throttle bodies. Just curious... definitely not trying to start any ****.
PS. Is all this through a stock C5 exhaust?
I believe GM claimed the larger 02 airbox opening was worth five of the additional 20 ponies that the ZO6 gained. The cam change was five and eliminating the pup cats was five per side or ten total.
I made my opening larger than that as I'm trying to feed 500 flywheel horse instead of 405
As for exhaust. I'm running XS Power 1-7/8" headers with merge/spike collectors. Three inch hi Flow cats and 3" X pipe. It connects to 2-1/2" Corsa extreme from the axle back
Before taking the car into be dynoed/tuned again I would seriously look into a blade style MAF with a larger housing, I know you are after a certain look but I had a friend make over 40 hp after switching from the C5 style air intake with a Blackwing to a Halltech CAI with the blade style MAF - that was on a LS3 crate motor.
I think after your current round of mods the MAF is now your bottleneck.
Any reason you're only reving the car to 6200? Seems like it's still making power and hasn't fallen off yet.
I'm sure you're correct about the MAF being the new bottle neck. There's always gonna be a new "hafta-do" mod but for me, this car is done.
The dyno sheet was printed and I'm not sure why it stops at 6200. The computer screen showed peek horsepower at 6300 and carried without a hiccup to 6800. They didn't have anything hooked to the engine but said the dyno was set up based on mph. I don't get too wrapped up in the numbers since this is far from the fastest car I've owned but IMO it's just a nice driver and does everything really well. I'm happy and it's my recipe. Nothing special
12-01-2016, 05:35 PM
Induction system enhancement 
