403 LS2 FD - LS7 Build for 2020!

[Exidous]

I'm really curious to see what your tq curve looks like. Our engines are rather similar except I have the MSD intake.

440 11.8:1
Tsp ported to 265cc
234/248-116.5+3.5 .660"
Ported MSD
Will be dual Bosch 82mm TB soon 116mm equiv single.
Ronin headers modded for the DCT. Single 3.5" put back.

Dyno'd an impressive 518rwhp with stock intake, 90mm TB and slightly smaller cam on a Mustang dyno.

What all needed trimming on the hood? I've always liked that hood. If it was made without the center port I'd have bought one by now.

I'd measure fender to ground. I've always ran 25" front and rear.

[MPbdy]

I'm really curious to see what your tq curve looks like. Our engines are rather similar except I have the MSD intake.

440 11.8:1
Tsp ported to 265cc
234/248-116.5+3.5 .660"
Ported MSD
Will be dual Bosch 82mm TB soon 116mm equiv single.
Ronin headers modded for the DCT. Single 3.5" put back.

Dyno'd an impressive 518rwhp with stock intake, 90mm TB and slightly smaller cam on a Mustang dyno.

What all needed trimming on the hood? I've always liked that hood. If it was made without the center port I'd have bought one by now.

I'd measure fender to ground. I've always ran 25" front and rear.

Yea I’m super curious too. You’ve got more cubes, more compression, better heads, and the best pound for pound ls7 intake available.

The hood trim was just the small section of flat in the front vent. You can see it in the close up picture. I agree I’ve always wanted this hood with no front vent it would be the perfect swap hood.

[Exidous]

I've always liked the look of painted carbon where just the vents are bare. Would make covering it up pretty easy.

[MPbdy]

I got my car on a dyno on Sunday!  I know there's going to be some huge skepticism in the numbers, but the car is very fast...and pulls relentlessly.  I got a Dragy and I'm excited to give it a shot and see if I can put up anything that would actually back up this kind of horsepower.  It has got to be pushing a low 6 or even breaking into a high 5 60 to 130 time.  I did however on my first drive home in a few years get popped going allegedly very fast and am still waiting to get the love letter in the mail to see what all that is going to entail.  I ought to maybe not risk that happening again until I know what the outcome of this debacle is...

Beyond the numbers, I'm extremely excited about the power curve and just how freaking fast the car is in every gear at every rpm.  I don't care if the dyno says 530 or 630, I have finally achieved my goal.  I've put so much effort into figuring out how to build a high rpm powerband that is properly suited for a sportscar without needing a massive camshaft.  Typically with a normal long runner intake and a small cam you wind up with just a huge lump of torque in the midrange that runs out of breath early like my old combo that fell like a rock above 6000rpm.

The key to the whole combo is the Holley sniper low pro.  This thing performs like a super victor single plane intake, in a low profile front feed package.  Unfortunately it won't fit under the stock hood, and because it is undamped sheet metal it is really noisy at idle, but when you're actually out driving the car with the hood on it the noise is not so bad.  The high rpm performance is out of this world.

I also spec'ed the cam myself with high rpm in mind, and built the valvetrain planning to spin this thing to 8000 rpm if it wanted it.

It is super tractable and predictable to drive with how flat and broad the torque curve is, and you can really get on it at lower rpm and it doesn't just ignite the tires which is exactly what I was looking for.

More or less the TL;DR:
The SAE corrected dyno numbers
91 octane:
616whp @ ~7000 rpm, 552 ft lb @ ~5300 rpm
E85 (E65 blend):
614whp with 4 more degrees of timing, and .5 afr leaner

> 600whp from ~6200rpm to 7500rpm, and pulls to 7800
>500whp from ~3500 rpm to 6500 rpm

Now, because the numbers were so unbelievable, I wanted to know what the uncorrected numbers were to give them the sniff test.  I had the weather station data from the dyno, so I worked backwards with a calculator and saw the following

Uncorrected 91: 594whp
Uncorrected E85: 586whp

Being an inertia drum style dyno, uncorrected numbers are what they are...kind of hard to fudge those.

We noticed an issue where the morning runs made a lot more power, and then as we tried to make more it seemed to fall off even with a lower coolant temp.  Also, the e85 runs made less power, and it was at a lower coolant temp because the ethanol cools the engine so much.

Well, my fans don't come on until 195, and with the cooling fans off the intake was sucking hot air back in through the radiator at high rpm.  It would start at ambient, and by the end of the pull the air temp was 100 degrees.

So, I took the IAT and baro readings and re-did the SAE correction factor and got the following

91 octane: 610whp SAE
E85 SAE: 620whp SAE

This makes a lot more sense with the E85 results, and gives a second route to calculating out a 600whp result.

I will do my best to try and backup the numbers someday, but my primary goal was the driving experience over total power, and for that without a doubt I'm saying mission accomplished.

LS7 SBE 427, 11.4:1
Comp low shock lobes 234/247, .665/.658" lift (1.82 ratio), 116+2
Stock ls7 heads w/ Ti intakes, Ferrea exhausts
4.150 .040" cometic gaskets
Johnson 2116SLR slow leakdown .093" travel
PAC 1207x .700" lift springs
TSP roller tip 1.82 rockers
Melling 10296 high volume/high pressure
Improved Racing Fbody pan trap door
Meziere EWP
ATI damper no underdrive
Tilton 246 twin disk organic clutch w/ sprung hub and strapped floaters
1 7/8" headers into dual 2.5" xpipe
Holley HP EFI with Flex Fuel



PS: the RPM is approximate - like the dyno sheets that show mph at the bottom with no torque curve.  At 7500 rpm it displayed ~7300 rpm on the dyno sheet.  At 2000 rpm it was within ~10-20rpm.  Close enough haha.  The torque values are reporting ~15 ft lb high because they're back calculated from the rpm value with a small percentage of error in it.

[MPbdy]

https://www.youtube.com/shorts/KW79esR2imE

Here's the video screaming out to 7500

Feel free to troll on the rotary bros in the comments.  Amazing this is still happening lol.  I thought in 2025 we could be free from judgement and persecution LOL

My buddy Daniel Kuo, DK from Garage Life was nice enough to lend us his dyno.  He's a firefighter going into paramedic training and a proam drifter with a shop on the side. Damn overachievers lol.  If you're in socal and need dyno or tuning work I'd highly recommend.

[Exidous]

The corrected numbers for e85 make sense. Unless someone was running massive 14+ cr I've not seen e85 make more than 10-15 on an LS7. The chamber design is just too good.

Still rather surprised at the numbers. I was expecting around 570-580. I've not been on a hub dyno. Will be once I get this new intake sorted. Shainiac said I HAVE to do a side by side between the 90mm TB and my dual 82mm with crazy neck.

Minus the ticket, congrats on the achievement. Not many break 600 outside the trans axle Vette folks.

[MPbdy]

The corrected numbers for e85 make sense. Unless someone was running massive 14+ cr I've not seen e85 make more than 10-15 on an LS7. The chamber design is just too good.

Still rather surprised at the numbers. I was expecting around 570-580. I've not been on a hub dyno. Will be once I get this new intake sorted. Shainiac said I HAVE to do a side by side between the 90mm TB and my dual 82mm with crazy neck.

Minus the ticket, congrats on the achievement. Not many break 600 outside the trans axle Vette folks.

You're telling me!  I was super pessimistic going into the dyno compared to everyone else.  I would've been shocked at 570-580 even.  End of the day its a stock headed ls7 with some nice parts and a small cam lol.  Never would've guessed ever that the number would start with a 6.  Even in a vette, I've only seen 600whp out of small cammed engines with Mamo 265's and ported MSD, and I've only seen one or maybe two combos like that.

I could come up with a scenario where it should make 570whp, but didn't believe it possible with 2.5" exhaust and small cam.

The intake and cam working together to peak at 7000 rpm, which is also around where the stock heads at 259cc/~2.8 MCSA tune for best power I think is the key.  These intake runners also have a huge taper which should increase velocity at high rpm and help continue to feed air even with the smaller cam duration and the unported heads.  I'm surprised even with a 105mm tb I'm seeing some KPA drop through the dyno pull.  It is really pulling in some air.

It is unimportant, but because its such an outlier result I would like to get it on a different dyno someday just for fun. 

On an old C5Z I had converted to flexfuel using a Tahoe computer, I actually lost 5whp at peak, but gained ~12 ft lb down low even on a knock limited engine like the LS6.  If the engine doesn't need more octane, I believe that Ethanol makes less power than gasoline.  However, the cooling effects and having an excess of octane where you know it'll never spark knock is super nice.  Throttle response is really good too.  I had hoped for 10whp with this combo just because on pump gas the LS7 typically maxes out in the low 20's for timing, and I had a tiny compression bump up to 11.4:1.  At 12:1 I think e85 would've shined a bit more, but I'm happy its not on the ragged edge with 91.

My buddy's dyno was an inertia drum, but he did not have the brake add-on like I hoped so my part throttle tuning didn't get any love.  The more I drive it with learn turned on the worse it is getting at low speed lol I'm going to actually have to put some effort into street tuning it, or have someone remote tune it if I'm too lazy (or can't figure it out). I still have a bit of work to do from a dead stop, and below 2000 rpm.

I'd be stoked to see another dyno from your car, especially wiht the dual inlet.  Super cool design!  I'm hoping it is in the tune, but it is really tough to take off from a stop smoothly in my car right now.  You lean your foot on the throttle and the RPM jumps up over 2000rpm.  If you ease up on the gas while trying to creep off the line the rpm gets drug way down and then it starts bucking.  Having a more progressive throttle at tip in would be super helpful.

When you dyno yours, and if you're on a dyno you can control steady state speeds, you should mess around with your throttle opening position and your fancy ECU to find best torque output at different RPM's.  You may find that it'll make better midrange with a closed down throttle.  I bet you could program a throttle position vs pedal TPS vs rpm table.

[shainiac]

Impressive numbers! I bet that thing is a riot on the street. How big was the ticket? lol

I'd bet money that your accel enrichment is off and that's throwing off your lower RPM fuel auto-tuning. If AE is whack, it'll make the engine run rich or lean, and the ECU can start pulling fuel from that portion of the map. The annoying thing about tuning AE is that your VE table needs to be pretty close to start lol. Bad AE tuning is also responsible for a lot of "dead spots" when making changes in throttle, and can become a closed loop if herky jerky driveability causes your foot to come off the pedal. All that is made worse by a giant throttle body, since you probably get all the air flow the engine needs for 2500rpm at maybe 30-40% TPS. One big perk of DBW is being able to add more resolution to the pedal and give you more finesse for low-throttle driveability.

[MPbdy]

Well, the top of 3rd is 118 mph and I didn't start slowing down very much before he shot me lol.  I was already getting on the brakes, and one he poked his wheel out from the driveway he was hiding in I stopped basically where he was parked.

You're exactly right I believe on the tip in issues.  I took about 50% of the AE out of it already but was waiting for after the dyno tune to dial it in.  I need to clear my learn table and lock it out in the tip in range and pull some more fuel out of it.  Its funny, I assumed it was a lean hole while driving but it is just completely flooding it based on the O2 sensor.

[Exidous]

I've not decided for certain if I'm going to run the TB in parallel or staged. I'll do parallel initially for simplicity. Maybe I'll be able to get the tip in curve mild enough so it's not too jerky.

I had some parts 3d printed in aluminum and they were just shipped. Should look like a complete engine bay again by the end of the month.

What's your exact valvetrain setup again? On the stock intake mine was nosing over quite hard and I'm not certain if it was instability or restriction. I'm using ti intake, .080 3/8 rods, 430 open prongs and trunioned stock rockers with Johnson linkbar lifters(hydraulic).

[shainiac]

I'm not familiar with Holley, but Maxx has settings to basically lock out the closed-loop fueling for a selectable amount of time after an AE or fuel/spark cut event. This prevents closed-loop from trying to fix AFR issues that aren't directly caused from the VE table. Might be something to look into. AE is a pain. I find it easiest to adjust in high gear, since you're not getting big rises in RPM when you make big throttle changes. AE is usually scaled by %TPS/s rate of change. So the faster you make changes in throttle position, the higher up the Y-axis you'll be on the AE table. You can try doing it with logs, but it's definitely easier with a friend in the passenger seat who is at least familiar with the software. You want to make the throttle change and then hold for at least a couple seconds so that the negative %TPS/s of lifting doesn't also affect your fueling. IMO, tuning AE is one of the more annoying parts of getting good driveability, but also one of the most important.

[MPbdy]

What's your exact valvetrain setup again? On the stock intake mine was nosing over quite hard and I'm not certain if it was instability or restriction. I'm using ti intake, .080 3/8 rods, 430 open prongs and trunioned stock rockers with Johnson linkbar lifters(hydraulic).

Here's the valvetrain specs.  BTW - we have two engines now with melling pumps where the oil pressure is dropping at high rpm.  This ls7, and our ls3 stroker for our drag car.  It is unsettling for sure, but it is repeatable every time and I've had no other issues with it.  Oil pressure peaks at 6000 rpm around 66psi, and falls off linearly ~6psi by 7400.  I just can't figure out why Melling pumps would exhibit this behavior.  The stock pump never did it.  I believe it is the 10296 pump in both engines.

Ti intakes, stainless exhausts
Johnson 2116SLR slow leakdown .093" travel
PAC 1207x .700" lift springs
TSP roller tip 1.82 rockers
Manton 3/8" x .095 wall pushrods

I'm not familiar with Holley, but Maxx has settings to basically lock out the closed-loop fueling for a selectable amount of time after an AE or fuel/spark cut event. This prevents closed-loop from trying to fix AFR issues that aren't directly caused from the VE table. Might be something to look into. AE is a pain. I find it easiest to adjust in high gear, since you're not getting big rises in RPM when you make big throttle changes. AE is usually scaled by %TPS/s rate of change. So the faster you make changes in throttle position, the higher up the Y-axis you'll be on the AE table. You can try doing it with logs, but it's definitely easier with a friend in the passenger seat who is at least familiar with the software. You want to make the throttle change and then hold for at least a couple seconds so that the negative %TPS/s of lifting doesn't also affect your fueling. IMO, tuning AE is one of the more annoying parts of getting good driveability, but also one of the most important.

The Holley is exactly the same.  I've seen where you just start in neutral and kick the throttle slowly a few times and make tweaks until the responsiveness is how you like.  Then do some faster and larger throttle movements.  It seems like a crappy thing to try and do lol its not a very repeatable process.

[shainiac]

Doing AE in neutral is no good IMO. You sweep through the RPMs way, way too fast. High gear allows you to stay in roughly the same RPM column of the AE map so you can dial in each column at each %TPS/s. I've never had much luck tuning it in neutral. a hub dyno with RPM/speed hold is ideal, but the lower driveability RPMs of the AE map can be hit in 5/6th on the highway.

[MPbdy]

Doing AE in neutral is no good IMO. You sweep through the RPMs way, way too fast. High gear allows you to stay in roughly the same RPM column of the AE map so you can dial in each column at each %TPS/s. I've never had much luck tuning it in neutral. a hub dyno with RPM/speed hold is ideal, but the lower driveability RPMs of the AE map can be hit in 5/6th on the highway.

That's good advice.  Driving on the freeway the car FEELS great.  If the car took off from a stop properly I'd call the tune "done" but I'm sure I can improve.

For AE, what's the ideal - do you want AFR to stay as close to target AFR as possible, or do you want to actually dip to the rich side on transients?

[shainiac]

I try to keep it on-target. That way closed loop fueling isn't trying to chase it's tail. Changes in TPS usually mean changes in MAP, which also probably means you're lambda target has changed too. So keep that in mind.