LS2 swap under way

[riggs 74]

Sorry, I've been busy for a while and hadn't had a chance to send and update.
I did take the car to the dyno and the dyno numbers are no where near where they should be. The car runs fantastic, but the numbers are about 70 up off from where I thought they should be. I am going to do some research on why they were so low and see if maybe it's in the tune still, I trust the shop I was dealing with but can't understand why I'm missing my target number.
I'm hoping to get a street recording from the car and send it off to frost tuning, the guy I was working with for the street tuning, and see if he sees any lost power.

The motor with the 550hp LS2 trick flow combo and the 402 bottom end, I feel the motor at the crank should be around 570 to 580 Hp. The rear wheel HP Only ended up being 415HP 402tq.
I feel I should have been at least 470 rwhp OR better.

Kind of reminds me of the disappointment that KAOS (Rob) had to deal with on his LSX 427, I wonder what he finally ended up with.

Right now the car runs great, I will find more power in the future, maybe with a larger cam.


Sorry for the disappointing story?

I hope to get a little video of the car real soon since I now have GOPRO2 working.

Riggs

[7TRoadster]

Engines can be weird that way. When I pitted on the race car (modified production drags) We would build 2 engines, with exactly the same parts, tolerances, procedures and tune. One would sometimes produce 50hp more than the other. Never did figure out why.

415HP is nothing to turn your back on, that is very respectable power at the rear wheel.

How are you figuring what the combo of parts should make? I've used software to do that and discovered that the software is usually more generous with HP than reality.

You might also inquire with Trick Flow on how they came up with their HP numbers. You might discover they were using higher compression, race gas, manual trans or something else different.

I'm interested to see what your tuner says. Do you have graphs of the computer stats during the run? Might be interesting to see how it was doing mixture wise, timing, etc.

As always I know you will figure it out.

[riggs 74]

Talking with my machinist that built the bottom end for me, He ball parked the HP to be around 570 to 580 with the heads and cam from trick flow.

Before I ordered the Trick Flow package I asked them how they tested the HP rating, They told me they used a stock 6.0 short block and intake with long tube headers to achieve the 550 FWHP, so with the Trick Flow Package and the 11:1 stroker kit I should be at around 570 to 580 FWHP, If that is the case then I am losing about 30% to 40% through the drive line, Thats about 155 HP lose.

Hopefully I'll find the lost HP


Riggs

[7TRoadster]

That does seem like allot of loss if the HP is close to the estimate. If you want to send the cam specs, compression ratio, bore and stroke, head flows, valve sizes and other engine information. I can drop it into the Desktop Dyno to see what it says.......... Up to you.

[riggs 74]

Sure, that would be great. Let me get the info together and I'll send it to you in the next day or so.

Thanks,

Riggs.

[riggs 74]

70T, here are the Specs to the LS let me know if you need any other info and don't make this priority over anything else you have going on.

Some of this info was cut from Trick Flows web site.

6.0 LS2 block 402 Stroker bottom end,

4" forged Callies crank
6.125 forged callies rods
Wiseco 4.005 -8cc dish ,

Stock LS 2 corvette intake with 42# injectors

Trick Flow upper end,
Camshaft, Hydraulic Roller Tappet, Duration @ .050 in. 238/ 242, Lift .595/ .595, Chevy, 4.8, 5.3, 5.7, 6.0L
Cylinder Heads, GenX® 225, CNC-ported, Aluminum, Assembled, 65cc CNC Chamber, Cadillac, Chevy, 6.0L LS2, Pair

Material: Aluminum

Combustion Chamber Volume (cc): 65
CNC-Machined Combustion Chamber: Yes
Intake Runner Volume (cc): 225cc
Exhaust Runner Volume (cc): 80cc
CNC-Machined Intake Runner: Yes
CNC-Machined Exhaust Runner: Yes
Intake Port Shape: Cathedral
Intake Port Location: Standard
Exhaust Port Shape: Oval
Exhaust Port Location: Standard

Intake Valve Diameter (in): 2.055 in.

Exhaust Valve Diameter (in): 1.575 in.
Valve Springs Included: Yes
Maximum Valve Lift (in): 0.600 in.
Outside Diameter of Outer Spring (in): 1.300 in.
:
Number of Springs Per Valve: Dual
Retainers Included: Yes
Retainer Material: Titanium
Locks Included: Yes
Lock Style: 7 degree

Intake Valve Angle: 13.50
Exhaust Valve Angle: 13.50
Valve Seat Machine Style:




Thanks 70T,

Riggs

[brent319]

Just how damn fast do you want to spin your tires? :-)
Just kidding I understand wanting to find the lost hp after all the time and money you put into it.
What kind of a dyno were you using?
The car kicks ass as it is, but I hope you can figure it out.

[7TRoadster]

Riggs, See if you can find flow volumes at different valve lift points. I have created a graph based on what is in your note. 225 at .595 lift. What I saw as max and max. I used data points at .200, .300, .400, .500, .550 and .600.

While I think this will run the simulation it would be good to have hard data if available.

Working on it now.....I'm sure there will be more questions.

[7TRoadster]

OK, so here is what the Desktop Dyno shows, granted this is with estimated flow numbers on the heads.......this could greatly improve output. The cam profile was as close as I could get, not exact but I didn't purchase the extra software parts to be able to draw in the exact cam profile.

So here you go..............

[riggs 74]

Couldn't get it to copy and paste with my phone so here is the web page, http://static.trickflow.com/global/i...genx%20225.pdf

Thanks, 70T
Riggs

[7TRoadster]

Well that did make a huge difference, brought the numbers up to about what you were expecting. Round two below.

Did you calculate the compression ratio? I only had bore, stroke, piston dish and head volume to work from. Got it as close as I could but seems a little high for a pump gas engine.

[riggs 74]

70T, that is much lower than what trick flow said it would do on just a stock ls2 short block. I take it that is fwhp that your program is showing?

I've kicked around the thought of a new 102 fast intake and throttle body, but at the wheels I would probably only see a 10 Hp gain from that 1500 expense, not really worth it.

I still need to record the tune and send it off to Frost tuning and see if he thinks there is room for improvement with the current tune. Hope I can do that this week.

70T thanks for taking the time to get me those results from the desk top dyno.

Riggs

[riggs 74]

70T I forgot to mention the compression ratio, its at 11:1 probably won't make that big of a difference.

Riggs

[7TRoadster]

Riggs,

Glad to add more data to the lost horsepower mystery. Yes the ratings are FWHP, there are no provisions in the software for drivetrain.

What level of fuel pressure are you running? Are you able to see O2 sensor stats for your runs? Thinking out loud but wondering if fuel flow is keeping up with demand.

[7TRoadster]

Hey Riggs,


How is the search for the lost HP coming along. Any news?