progress on the banshee...

[pmbrunelle]

It's probably a good idea to keep the fuel pressure regulator line separate in case of some BOV piston leakage.

When considering the BOV piston leakage as a vacuum leak for the engine in a general sense, I don't think it's an issue.

I have the exact same Turbosmart BOV on my car.

I think that a rubber lip seal would add friction and probably wear over time.

Trumpets use piston valves (Teflon-looking coating on the piston which slides in a metal bore), and they seal enough to work. A combination of lubricating oil and saliva from the musician fills the piston-to-bore gap. In a trumpet, the actuation force needs to be low enough to avoid tiring the musician's fingers. I played the trumpet for four years when I was in school from grade 7 thru 10!

[ericjon262]

You're supposed to have enough blow-by oil in your PCV air to fill that gap and keep the piston sealed

It's probably a good idea to keep the fuel pressure regulator line separate in case of some BOV piston leakage.

When considering the BOV piston leakage as a vacuum leak for the engine in a general sense, I don't think it's an issue.

I have the exact same Turbosmart BOV on my car.

I think that a rubber lip seal would add friction and probably wear over time.

Trumpets use piston valves (Teflon-looking coating on the piston which slides in a metal bore), and they seal enough to work. A combination of lubricating oil and saliva from the musician fills the piston-to-bore gap. In a trumpet, the actuation force needs to be low enough to avoid tiring the musician's fingers. I played the trumpet for four years when I was in school from grade 7 thru 10!

I'd rather replace it with a diaphragm operated valve, using a mighty vac, pumping as fast as I can, I can't keep up with the leakage past the piston.


Earlier I had dismissed the LA1 flexplate because the flywheel didn't fit flat on the flange, in a PM, Will mentioned this could be an advantage, a spacer can fit the flywheel, and be used as a centering device. I like this idea better than most that I had explored thus far.

I inverted the flywheel, and then set the LA1 flexplate on top, I then took plunge measurements through the bolt holes of the flexplate to the flywheel, the distance. I came up with about 5mm, I then subtracted the thickness of the flexplate, about 2.6mm, coming to a difference of 2.4mm. a 3mm spacer should bring me to right where I need to be. now I need to get measure the bolt pattern, and draw the spacer up.

[ericjon262]

I try to drive the car fairly frequently, and I'm trying to pay close attention to the quirks the car has, so I can narrow down their source. As of most recently, I've found a few things that need attention.

1. Fuel pressure, and it's response to manifold pressure. this is important to me, but from a functionality standpoint, the car operates ok with more or less static fuel pressure.
2. Fuel tank. I have a new one on the way from Rodney, I'm looking forward to getting it installed, my current tank has a leak on the top where the sending unit O ring is, while I could just replace the O ring, I like the idea of a new tank that's clean, and has good baffles still.
3. during the numerous attempts to fix the ongoing fuel pressure issue, the car developed a vacuum/boost leak, or the throttle body is trash. more on this below.
4. there's something in the rear suspension making the car handle poorly, alignment isn't dead nuts perfect, but it's pretty close, I'm suspecting the trailing link bushings are shot and need to be replaced. anyone have a recommendation?
5. upper control arms, the car needs more caster. I'm working on a solution for this, it won't be elegant, but it should work.

I'm beginning to question the fuel pressure sensor on the car, I've started to notice some trends that don't make sense. I have a replacement on the way.

during the troubleshooting process for the FPR, I pulled the plenum, and installed a new TB because the fitting on the TB I was using for the BOV cracked while tightening it. after replacing the TB, I had a very high idle state, and throttle position had to be lowered about 4% to maintain the same idle RPM, I suspected a vacuum leak, I checked a ton of stuff. and can't seem to find an actual leak anywhere. The new TB was a new, GM throttle body, not, a cheap aftermarket part, but I'm beginning to suspect it's the root of my issues. I lost all throttle control, the DBW fault light on the TS dash did not light, the throttle just stuck at about 8.4%. I put the car in neutral, pushed the gas, nothing, I put it in 3rd or 4th, let the clutch out, rpm goes down a bit, then the throttle jumps to 22.7%, with the accelerator pedal reading 7.82%, taking my foot off the pedal entirely brought TPS to ~21%, and then it stayed there. turning the car off, and restarting it regained control.



Zoomed in to show APP movement with no throttle movement:



zoomed in on the runaway throttle:



about 10 minutes later, same thing, except this time I didn't try anything with the clutch.



I put way more miles on the old TB, and never saw anything like that, so I attempted to repair the old TB, and am going to repair and reinstall it to see where I end up. I'm also going to replace the oring in the TB adapter.

here, you can see the new fitting fixed to the TB, and the new fitting installed in the boss on the plenum that is now solely for the FPR. I'm going to make a clip to hole the hose, and wiring harness off of the valve cover a little bit.



tomorrow I'll try swapping the TB.

[ericjon262]

I swapped the TB, didn't drive it until today though, interestingly enough, the new TB required about 3.5-4% throttle to idle, the old TB about 7-8%, I assumed this was a vacuum leak, but when I swapped the old TB back, I came to a stop and the car straight up died... I had to keep a foot on the gas until I could make an adjustment in the tune, bumped it back to 7% for full shut, and ta-da! it's back to the way it was. when I was swapping the throttles, I held both up to the sun and looked at them closed, it did appear the new throttle let more light passed the blade. that said, the test was hardly scientific.

The new TB was supposed to be a new GM unit, I'm beginning to suspect that it was counterfeit. I've seen more than one report of counterfeit parts coming from rock auto, but that's only a hunch, I have no way to validate that other than spotty operation and apparent loose tolerance compared to a stock take off part.

since I was able to repair my old TB, I'm going to continue to run it, and see if the control issue I posted about earlier rears it's head again.

[ericjon262]

I've been working on dialing in the car a bit at a time every time I drive it, and I'm pleased to say great progress has been made.

I had been running open loop idle control for a while, and was getting pretty good idle quality, with no IAC scheme of any kind. I enabled closed loop idle control, and was having a ton of trouble, the car wasn't wanting to "drop"(for lack of a better term) into idle, it would hang up and hunt badly. with the DBW throttle, a PWM signals the throttle to open or close for idle control, this PWM signal is a 0-100% signal, and is scaled to the "Max idle addition" set in the DBW controller. The MS3 has two means of returning the engine to idle, it can either use the last PWM value as the starting point, or use a table based on coolant temp and desired idle speed. I had it set to use the last value, but when I changed it to use the initial value table, and populated the table, it seemed to return to idle quickly and maintain idle much better. My last datalog shows idle being maintained in a 25 RPM band, considering the engine has a smedium cam, and an aluminum flywheel, I'd say that's pretty good, and I would imagine will continue to improve as I tune further.

I found this tutorial on idle tuning, it's a little bit out of date, but I'm going to play with some of concepts and see if I can make it any better, ideally I'll improve idle quality during cooling fan on/off transitions.

https://www.youtube.com/watch?v=5odey_8 ... xEFITuning

Speaking of the cooling fan, I really need to fix the mounting of my cooling fan, when it runs it hits the shroud, maybe I'll work on it this weekend.

I had been mostly using MLV's VE analyze feature to tune the car up until this point, here lately I've been doing more hand tuning, and trying to run the engine steady state at multiple RPM ranges as long as possible to try and get good data for dialing in the VE table.

[ericjon262]

Finally made it to the track

First run was about 8 PSI and a lean on the big end, 2nd run was 10 PSI, and closer to a safe AFR. there's still a ton left in it, even at this boost level.



https://youtu.be/N9kgq1Ecdcg

https://youtu.be/NnyFvMRTnKo

[ericjon262]

Earlier this week I enabled boost control and was and have been slowly trying to dial it in. I took it to the track in an attempt to safely explore the operations of the boost control solenoid.




it was a disaster... I was only able to make 2 passes, the first, bogged hard on the line, and went very lean, the second, hooked ok, but also went lean, but in the same spots/loads/manners as the first pass... thankfully, I was running fairly low boost, only about 4 PSI.

now, the important question, why did it go lean? the VE table got significantly fatter in the regions it was going lean yet still went lean, and then, on the way home, got worse... at this point, I'm guessing the fuel pump, or the fuel pump relay is going bad. I have one of rodney's fuel tanks, I guess I'll need to start putting together the fuel system sooner than I thought. I'm going to keep driving it and keep an eye on AFR's and see what happens, then once I have the Gran Damn back together, I'll see about pulling it into the shop.

[ericjon262]

I need your thoughts.

The car runs and drives, so I intend on leaving it alone for the most part until I have a new engine ready to go in. it does need work, the valvetrain sounds like death, and the cam bearings are shedding little bits of themselves into the oil...

I see 3 ways this could go:

-build the LX9 I have in the garage, go for broke, pistons, rods, solid roller lifters ect.

-a more stockish LZ9 with a my turbo.

-a "built" LZ9 with my turbo.

I eventually want to put a 3900 in the car, with functional VVT. However, there are no camshafts available for the VVT engines, that retain VVT, which means I have to figure that out myself, either via a reground stock cam, or other terrible ideas.

building a LX9 will be about as much work as building a LZ9, and be short .4L of displacement with not quite as awesome of a cylinder head. if I wanted to get really crazy, I could have the LZ9 crank ground and build on the 3.9L to maybe over 4.0L, but I don't think that's in the cards. And if I want to put an LZ9 in the car, why go through the extra trouble of putting another 3.5 in?

I need to meet one of two conditions to trigger a new engine swap.

-Failure of the engine or transmission that requires removal from the car.

-a new engine and transmission(wanting to put a quaife in) is built and otherwise waiting for install.

I'm not even sure I want to pull the engine until it lets the smoke out, and I'm fine with taking it to the track and torture testing it until it does.(will need to invest in a engine diaper before that...)

it just doesn't seem to make sense to me, to take the intermediate step of running another LX9, and I welcome the thoughts/opinions of the rest of the RFT gang on the matter.

[The Dark Side of Will]

The major factor in keeping VVT with a bigger cam is piston to valve clearance. If you're doing a mild build to experiment with bigger cams and VVT, then you can take the opportunity to install pistons with deeper valve reliefs.

[Shaun41178(2)]

What's your HP goal with either built engine or stock?

[ericjon262]

The major factor in keeping VVT with a bigger cam is piston to valve clearance. If you're doing a mild build to experiment with bigger cams and VVT, then you can take the opportunity to install pistons with deeper valve reliefs.

for sure, it would very much be an important consideration

What's your HP goal with either built engine or stock?

I think my current engine could meet my goals, I'd like to be capable of mid to low 11's in the quarter. which a turbo 3900 in any form should be more than capable of. built or not, there WILL be a cam going into whatever engine goes in the car.

[Shaun41178(2)]

Yes, a stock lx9 can meet your ET goals mine made 530 whp on stock bottom end. You will prob need 450 whp to run mid to low 11s I would guess. That's prob 15ish lbs

I wouldn't build a forged lx9 for 11s

[ericjon262]

Yes, a stock lx9 can meet your ET goals mine made 530 whp on stock bottom end. You will prob need 450 whp to run mid to low 11s I would guess. That's prob 15ish lbs

I wouldn't build a forged lx9 for 11s

11's is the current goal, but I'm open to wildly exceeding that goal, as long as the track officials don't look...

the only real reason to build it, is that I already have a set of H beam rods, and matching forged pistons, so I could throw it together much cheaper than buying all new parts. I won't put another stock LX9 together for this car for that reason.

[ericjon262]

I think for now, I'll go ahead and assemble the LX9 parts I have on hand right now, and work towards having an assembled short block ready to go into the car at a moments notice, that way if my current engine lets the smoke out, I have something I can rapidly throw at it and keep it going, it will literally cost me nothing but an afternoon to assemble, and a few gaskets.

once it's together, I'll grab an LZ9 that I can work on as time permits and I feel like messing with it. The big holdup, will be finding/building a camshaft, to call it a custom grind will be a bit of an understatement. the fastest option will be to send it to a regrinder, and have the base circle trimmed down a bit to gain a small amount of lift, and overall duration. the long answer is to get a piece of round bar, rough cut it for the positions of each lobe and journal, and then try and find someone to perform the finish grinding of the cam.

on either engine, I think I want to either limit the travel of the stock hydraulic lifters, or go with a solid lifter. if the valvetrain is going to be noisy, it's going to be a noise worth being proud of. if I have the cam ground for solid lifters, it will be a very mild solid roller grind, not quite as radical as most engines get in that kind of cam, this is for two reasons, one, my head flow peaks at about .550 lift, going much bigger than that sacrifices durability and overstresses valvetrain parts without any real benefit. two, the idea behind a solid lifter, is to remove the variable of the lifter hydraulics, and something a bit more bulletproof. every one of these engines I've messed with has/had noisy lifters, which usually means they are bottoming out and not working as desired. if the valvetrain is going to be noisy, it's going to be joyful noises, not bad ones.

Engine Masters did a dyno test of solid rollers on a hydraulic roller cam, and the solid rollers showed a performance gain on the hydraulic cam, with what were allegedly very good hydraulic lifters to start, so going from a poor performing hydraulic to a solid may show better gains, assuming their "very good hydraulic lifters" were actually very good. From a maintenance standpoint, the biggest concern is adjusting valve lash. in my head, the best way to handle this will be to do it how NASCAR does. NASCAR, or at least GM R07 cylinder heads, adjust valvetrain geometry in two ways.

1: the rockers are shaft mounted, and sit on a pedestal bolted to the head. the positioning of the pedestal via shims aligns the rocker to the valve such that at 50% total lift, the rocker tip is just outboard of the center of the valve, the centerline of the tip and fulcrum of the rocker is 90 degrees to the valve stem.

2: The rockers have no provisions for lash adjustment. the only way to "adjust" lash, would be to either run an adjustable length pushrod, or carefully measure pushrod length, and set lash after setting tip geometry. Adjustable length pushrods are a thing, but mostly only common on Harley Davidsons, I'm also not too fond of the idea, because they would just plain be a PITA to actually adjust, as almost none of the pushrod is accessible on a 60V6.

making a rocker pedestal capable of being shimmed would be a cake walk, worst case scenario, I machine a little off of the base of an existing pedestal. although I have a very basic plan for machining a run of pedestals the would be accurate, and simple enough.

limiting the travel of the stock lifters is also an option, but it's something I haven't given as much thought too. I'll have to investigate it significantly further, although the basic principle is pretty simple, put a block in the bottom of a lifter, now it can't go as far before acting like a solid lifter.

[pmbrunelle]

You can also get lash caps in differing thicknesses. Here is an example:
https://store.vacmotorsports.com/vac-mo ... p1677.aspx

Can the LZ9 valve covers be removed quickly while the engine is in the car? Would you want to verify valve lash while the engine is still hot?

[Shaun41178(2)]

Trunk side valve cover is easy to remove with the intake on. Firewall side is doable but you're blind doing it

[Shaun41178(2)]

Ls7 engines redline from the factory at 7k rpm. They have hydraulic lifters.

Fyi.

[ericjon262]

You can also get lash caps in differing thicknesses. Here is an example:
https://store.vacmotorsports.com/vac-mo ... p1677.aspx

Can the LZ9 valve covers be removed quickly while the engine is in the car? Would you want to verify valve lash while the engine is still hot?

it's kinda hard to say, my car is a little different than most, it doesn't have the hinge boxes anymore, which makes that kind of maintenance much easier.

The lash caps are a great idea that I somehow hadn't considered. thanks!

Ls7 engines redline from the factory at 7k rpm. They have hydraulic lifters.

Fyi.

truth. they also don't fit a 60v6 though, they're way too tall.

I'm mostly bothered by the fact that every set of these lifters I've had, have been very noisy, if I'm going to have a valvetrain that is that noisy, I'd prefer it be consistently noisy, and if it's going to be noisy, I want performance out of it. each set has had proper lifter preload as well.

[Jalisurr]

Ls7 engines redline from the factory at 7k rpm. They have hydraulic lifters.

Fyi.

They also have titanium rods to keep the rotating assembly light which wear out after 50k miles and spin bearings

...ask me how I know.

[Shaun41178(2)]

Ls7 lifters don't fit, but my point is they are hydraulic and work just fine at 7k rpm from the factory.

No need to go mechanical. My opinion.