403 LS2 FD - LS7 Build for 2020!

[kinger]

What is a good working OEM rack worth these days? 

I am contemplating a Grannas rack with the epower steering kit OR a electrohydraulic pump from like a mazda 3 or dodge charger, just to be able to control the assist with the ecu.  There is a company that makes a module for them now and super easy.  You do need a good leak free rack to start with though. 

When I priced options I was like wow $2k plus for a electric/manual set up is too much for a "nice to have" but then I see my rack may be worth enough to offset it partially. 

I love the reviews and feedback.  The parked with wheels cocked thing seems awful annoying!

[Exidous]

Kinger, Grannas is 20:1 only. Super slow.

I do have the ECU controlling the assist but it requires an ECU with an analog 0-5v OUT. Not many ECUs have that.

At speed I essentially have the assist as low as it can go. There is weight to the wheel so it's not bad. The "delay" in weight change is minimal. Under 1s for sure.

[paul_3rdgen]

I’m currently running the e-power steering kit.  I have an atomic Rex manual rack and without the power assist it is exhausting driving the car on the race track, my shoulders and arms are sore by the end of the day and I’m in really good shape for a 49 year old. 
   I agree that it takes to long for the unit to adjust to your input but once you find the right amount of assist I found it to be a game changer, I felt so much more relaxed on track.  On the street it’s great for parking and slow movements like parking my car on my 4 post lift.   I also set it to almost no assist for highway pulls.   

I’ve been thinking about changing the control knob to one with multiple settings, like one with 3-5 settings that click and locks into place.  Kinda like selecting a pre determined setting.   Do you guys think that will work?  And is it possible?   


Sent from my iPhone using Tapatalk

[digitalsolo]

It’s just a pot;  if you got a multi position one with the right values (or a universal that you add resistors to) it should be doable.

[Cobranut]

That's a good idea.
A rotary switch with resistors would allow you to dial-in specific assist levels that would be repeatable.

[Exidous]

Paul,

Test the resistance of the current pot. Find one on Mouser or Digikey with detents of the same resistance.

[MPbdy]

I'm keeping my steering rack!!!!!  My old man tackled it while I was wiring.  He was able to drill and pull out the side seal without taking the rack apart. Just had to remove the inner tie rod on the one side.  Such a relief. 



I posted up on the Facebook group so I think everyone saw already, but I was able to go for a real drive!  Took it out for 10-15 minutes and everything was perfect.  I only got into it really lightly on the throttle.  Just cracking this big throttle body gives you a lot of air, so I didn't putt around, but I really only got into it maybe 20% throttle.  The clutch, trans and r&p all need to break in and have fluids swapped out.

The new catch can routing is working perfectly.  Not a wisp of smoke came out.  You no longer smell like burnt oil after a drive (I'm hoping that remains true, maybe a real test will be a longer drive).

The Tilton clutch has a slight shudder on take-off, but my tune is horrible just off idle.  Right when the car starts moving the engine almost dies unless you feed it a lot of revs so I'm thinking with tune improvements and some break-in miles it should smooth out.  It feels good and natural to drive I'm liking it a lot so far.  Great news is the sprung hub and strapped floaters fully resolved my 1800 rpm vibration.  There's still noise at that RPM you can tell it is a harmonic point in the drivetrain, but there's no vibration coming into the cabin.

I have just a touch too little clutch travel at the moment. I need to see if I can adjust the clutch rod enough, or if I need to modify the pedal.  I'm feeling like I can't quite get it into 1st gear sometimes at a dead stop.  If the car rolls a little it falls right in.  I also had it balk on me going into gear a little if I wasn't perfectly on the floor (happened in the video going into 5th lol).  I don't think this is a matter of break-in, I think I'll wind up hurting the syncros if I don't fix it.  I'm going to be no lift shifting this thing so I want to make sure the clutch is fully disengaging lol.

On the topic of vibration, I continue to be amazed - this is the smoothest the car has ever felt.  In a big way.  I can't wait to really open this thing up and get it up to some triple digit speeds.  I ran it up to ~80 mph just cracking the throttle and going through the gears.  I think it is just years of refinement paying off.  When I had my old single disk with a sprung hub, I still had the Samberg OEM diff mount and lots of driveshaft issues.  There've been many incremental improvements.  The engine seems smoother than my last one, the clutch is a world better, fixing the driveline lateral alignment, and road force balancing the wheels and tires all were major contributors. 

After YEARS and multiple sets of gears, swapping to Ford Racing 3.73's finally fixed my gear whine issues.  Different manufacturers, REM polishing - nothing prevented the gear howl with 3.90's.  I know I for sure had two sets of 3.90's...maybe 3. 

The car sounds really really good - it is surprisingly a lot quieter than the 402, which is odd.  This LS7 is more cubes and has more overlap, but is way less rowdy sounding.  Makes me think the cam might need to be a little bigger    The goal was to make it a better street car so I can't sabotage myself unless it really doesn't run how I want haha.  I always have the big motor to throw in later.

Left to do is just really simple stuff:
I/O module wiring
Tuck the wiring inside and finish install the ECU
Reinstall all the interior and mount the Holley screen
Clutch adjustment
Fit the hood
Alignment appointment
Tune, break-in, fluid flush and dyno appointment
Professional paint correction and cermic coat if the paint looks good enough to justify it

Less critical:
I have a new map pocket to install
Need a new stereo and speakers
Oil cooler desperately needed
I'm really considering swapping to a BTR Trinity to get rid of the awful noise from this sheet metal unit, but will dyno first to make sure I like the powerband
Finish the 3d printed intake duct project
I want a skidplate. My oil pan gets scrapes, and its been punctured once hitting a giant rock
Finish my Porsche BBK project I started ages ago

[MPbdy]

I'm getting curious again about how much power this thing ought to put down, and what the curve looks like.

If I just do benchrace napkin math, my 402 made just over 510 at the axle.  As a 427 it would be ~545whp just for the increased cubic inch.

The 402 had stock ls3 heads, stock intake, smaller bore shrouding the intake valve, less compression, and a much smaller cam (226/242 on 117 with 600 lift vs 234/247 on 116 with 650 lift)..and would only horsepower peak at ~6000 rpm.

I have no concerns about reving this thing to 8000 if it'll keep putting out steam.  I'd be thrilled to see horsepower peak at 7000 or higher with this smaller cam.  The short runner intake manifold has the biggest impact on peak power RPM, and I also spec'ed the cam to close the intake valve around where a stage 3/4 cam does.  It is just a question now if 234 degrees of intake duration can keep getting air in the cylinder at that RPM.

So...if I took my 402 and put better heads, a bigger cam, more compression and a better intake manifold I would really expect serious jump in power, maybe up to 540 or 550whp.

That would put the 427 at 575-585 whp with the same hp/cube.

Does not seem possible in the slightest?

I'm really not sure why I'm so pessimistic, but I expect this thing to under deliver on power compared to the napkin math.  In the end, if it'll rev a lot and make 530whp I don't think I'm going to lose any sleep, but the napkin math isn't really much of a stretch.  I think my main holdup is I've scoped out soooooo many C6Z builds of all different levels, and I've never really seen a small essentially "cam-only" build make 550whp+, and vettes have very little drivetrain loss.

I have never cared less about power output though lol I don't race it anymore, and I don't have a dragstrip to take it down, so until I get a draggy I won't have to deal with the reality of how "slow" it is in compared to all these roll race fucks that didn't exist back in my day lmao.  It will definitely be enough to get rowdy.

[Exidous]

My 232/240 118 cam with stock ported intake was 520whp on a mustang dyno and 129-131mph. Now I have a ported MSD, electric everything and a nearly identical cam to yours. 234/248-116.5+3.5. Depending on compression, I don't think you'll have issues reaching those numbers. Plus you could always hop on a dyno jet. Haha

VIDEO NEEDS MOAR BEANS

[MPbdy]

Definitely need more beans!!  That's a great datapoint from your car thank you.  Yea, my old dyno was on a dynapak hub dyno that closely compares close to a dynojet.  I'll be on one or the other again for sure.  I'll also have flex fuel on this setup and I did not have flex fuel for my 511whp dyno with the 402.

Normally I'm pretty spot on with my predictions, but I don't trust it this time for some reason haha.  What might be getting me with C6Z comparisons is that no one typically is squeezing every horsepower out of a BTR Stage 1 cam swap lol.

It'll be a fun experiment with this intake - I've been chasing more of a "sports car" powerband for this car since I built it, and that is 100% the thing I'm most excited about vs a number.  One thing for sure, it did NOT feel sluggish when I drove it lol.

I mentioned the Trinity intake last post, but there's also the Holley Ultralow that might work too.  Looking at these dimensioned drawings I'm pretty sure I'm on crack though lol.  After I fit the hood I'll know how much real-estate I actually have.  My intake is 7" from the block valley to the highest point just behind the TB. 

Trinity has an LS7 port, but puts the throttle body really high and forward.



I really wish Holley had made an LS7 version of this intake.  This would need intake flange adapters that are .5" thick.

[Exidous]

From the comparisons I've seen the MSD reigns supreme for area under the curve unless you're building an 8500RPM monster. With my old cam and LS7 intake, the cable nosed over pretty hard at 6200. Peak power was around there. Was also a 90mm TB. I'm going to a dual bosch 82mm setup that's the equivalent of an 116mm single with the resolution of an 82 since they'll be staged. Shainiac has helped me out a bit on the modelling since I'm still a noob.

Joel was kind enough to send me his radiator without the top plate so I can make my own for the dual 3.25" filter setup I'll be running. I'd LOVE to see 600whp but no way that'll happen  without a cam in the 250s.

[kinger]

From the comparisons I've seen the MSD reigns supreme for area under the curve unless you're building an 8500RPM monster. With my old cam and LS7 intake, the cable nosed over pretty hard at 6200. Peak power was around there. Was also a 90mm TB. I'm going to a dual bosch 82mm setup that's the equivalent of an 116mm single with the resolution of an 82 since they'll be staged. Shainiac has helped me out a bit on the modelling since I'm still a noob.

Joel was kind enough to send me his radiator without the top plate so I can make my own for the dual 3.25" filter setup I'll be running. I'd LOVE to see 600whp but no way that'll happen  without a cam in the 250s.

Really excited to see your intake when done.  Are you using 8 different GPOs for the 2 e throttles?  I think it takes 4 per on MAxx. 

Ported MSD is what you want @MPbdy

[MPbdy]

Tony worked a C6Z package with a 237/249 on 114 cam that put out 635whp.  We're kind of pushing new boundaries with these LS7 builds in the FD chassis.  Not much info out there for NA combinations much over 550whp.  That is also part of my lack of faith haha.  I guess I'll start getting my hopes up a little more.  It would definitely be nice if we could more easily fit a larger exhaust and headers.

https://www.corvetteforum.com/forums/c6-corvette-zr1-and-z06/4312830-evolution-of-the-ultimate-small-cam-ls7-combo-eggcrate-v3-build-650-hp-580-tq.html

From the comparisons I've seen the MSD reigns supreme for area under the curve unless you're building an 8500RPM monster. With my old cam and LS7 intake, the cable nosed over pretty hard at 6200. Peak power was around there. Was also a 90mm TB. I'm going to a dual bosch 82mm setup that's the equivalent of an 116mm single with the resolution of an 82 since they'll be staged. Shainiac has helped me out a bit on the modelling since I'm still a noob.

Joel was kind enough to send me his radiator without the top plate so I can make my own for the dual 3.25" filter setup I'll be running. I'd LOVE to see 600whp but no way that'll happen  without a cam in the 250s.

Ported MSD is what you want @MPbdy

You're both not wrong - the MSD is by far the best all around option available, and somehow works for simple cam only builds all the way up to more extreme 650+whp combinations. 

Sacrificing 30-40 ft lb is actually a feature not a bug for me with this short runner intake.  I really want a tabletop flat broad torque curve like a single plane carb intake instead of the typical stair step lump of torque at ~4000 rpm that fades quite rapidly typical of the LS.  These low profile intakes from what I have seen appear to peak where a typical single plane intake will, but will carry very flat after HP peak.  I did originally choose this intake to pair with the solid roller engine with the huge cam, ported heads, more compression etc.

I also don't really want to buy a $2000 plastic intake that would cause me a lot of grief on throttle body fitment, cable routing, fuel rails and lines, and firewall fitment.

Even if performance is good with the low pro intake, but I can't find a resolution for the obnoxious sound it may force my hand into a change.

[Exidous]

Kinger,

It's just the two analog per throttle and two outputs for the motor. I'll probably have os SLS printed first in glass filled nylon like PA12 or 6.

The performance design carbon has the same low and midrange of the msd but carries well past 7500. Just have to contend with the extra 8in tall. Honestly, using an I take like yours makes sense for the chassis with an LS7. I have no shortage of low to midrange.

[MPbdy]

In a timely post, someone just posted up a gorgeous FD with a trinity intake under my same hood.

btr makes the runners for the ls7 port as well. But I'm not sure if you can still get this plenum with the turn down for the TB mount which is a must or the TB hits.

I haven't been able to find exactly what he's talking about with the throttle body turndown - I do see BTR references version 2 runners, but does not talk about a different plenum design.

I did also reach out to Ironmaskairflow to get his optionion on ultralow vs the trinity - says he doesn't love either bc of the torque loss but understands if its a fitment thing.  He said Trinity would be his preference.  Funny I was just so happy about my strut brace fitting, and immediately I'm looking at an intake that would interfere lol.

One step at a time first - I'll get some performance data from the short runner intake before making a move.

This car makes me feel like I don't know wtf I'm doing.