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Got the car on a dyno finally (dynojet). 269whp with 250ft/lb on 93 octane with overkill 80mm throttle body, jacfab ported intake manifold and spacer, and an overkill tune. Waiting on my E85 tune from overkill for a few months now, so one day it will be here. In the mean time I'm working with Griff to get it dialed in a little more and inch closer to 300whp on 93 octane.
THB, seems a bit low on power. Before I installed my ported TB and Jacfab ported intake i was at 306whp on 91 and 310whp on ethanol so i should be a little higher now. Hardly anything to be gained (power-wise), at least in my experience and tune going from 91 to E85. There is some cooling benefit to the ethanol, and thats really the only benefit i can think of as mine is a dedicated track car.
I know all dynos are different and you can't compare one to another, but that's a pretty huge difference. I forget,do you have an underdrive pulley? Power steering? Did you walnut blast the backsides of the valves?
THB, seems a bit low on power. Before I installed my ported TB and Jacfab ported intake i was at 306whp on 91 and 310whp on ethanol so i should be a little higher now. Hardly anything to be gained (power-wise), at least in my experience and tune going from 91 to E85. There is some cooling benefit to the ethanol, and thats really the only benefit i can think of as mine is a dedicated track car.
I know all dynos are different and you can't compare one to another, but that's a pretty huge difference. I forget,do you have an underdrive pulley? Power steering? Did you walnut blast the backsides of the valves?
-Ryan
Didn't walnut blast the vlaves, but did use a shotgun bore cleaner on a drill and they came out pretty nice. Engine only has 12k miles on it too. Interesting on the E85. I think ThePass put down something like 326whp on E85 with basically a stock motor. Yeah, I had the same thinking this was low, but not totally sure why. No power steering or AC, No underdrive pulley either. You confirmed my thoughts that it should be around 300whp on 93. Hmmm...
My motor had around 30k and the valves were pretty nasty, even with relatively low miles.
Not sure if his number was that high, but somewhere in there. I used the same tuner as Ryan (Sean Church), same exact dyno, and Sean and I hypothesized that the lower output of mine was due to my heavy OEM flywheel and clutch, whereas Ryan at the time had the Spec lightweight one as well as Ryan's side exit/short nice flowing exhausts where mine at the time were full length 2" (should be bigger) then through a large muffler at the back of the car. So more exhaust back pressure, and more flywheel weight to throw around.
I'm using the oem flywheel and clutch as well, but my exhaust is dual 2.5" from the engine all the way out the sides and a race muffler. No cats or really much any restriction.
It's hard/foolish to compare across different dynos, but that seems in range for stock. For example, mine dyno'd at 275 on 93 stock other than tune. One explanation is that the 80mm throttle body and ported manifold don't make much/any measurable difference.
THB, seems a bit low on power. Before I installed my ported TB and Jacfab ported intake i was at 306whp on 91 and 310whp on ethanol so i should be a little higher now. Hardly anything to be gained (power-wise), at least in my experience and tune going from 91 to E85. There is some cooling benefit to the ethanol, and thats really the only benefit i can think of as mine is a dedicated track car.
I know all dynos are different and you can't compare one to another, but that's a pretty huge difference. I forget,do you have an underdrive pulley? Power steering? Did you walnut blast the backsides of the valves?
-Ryan
Did you run into any misfire reporting issues while tuning?
Turned on misfires in the HPT scanner per Griff's recommendation to see how the engine was doing on the new tune. **** ton of misfires on cylinder #2 and a small amount on #5. Pulled a coil while running the HPT scanner to confirm which cylinders where what. From the front on the passenger side #1 - #3 - #5 (rear). Driver side from the front #2 - #4 - #6 (rear).
Moved coils around for test drive number one and still a ton of misfires on cylinder #2. Replaced spark plugs for test drive two and no changes. ****, starting to get into the stuff that is a hassle to fix. Just did a compression test and 150 psi on all cylinders. Yay! So I think we are narrowed down to a fuel issue now and I am assuming it leads to the injector since it is cylinder specific.
At this point everyone I'm talking with and myself believe I have at least one clogged injector. Found a place in Houston that cleans and flow tests GDI injectors for $25 each. Sending in the full set and will report back when I get them in. I'm using the corvette fuel filter, so that should be good enough. I can't remember flushing the lines once everything was installed though, so that seems more than likely the issue right now. Very curious to see if this fixes it.
Just got the new injectors in. Not for the faint of heart, it's a bitch.
It's late and some quick notes that might help some others before I forget...
Removing the rails can be done without removing the heads.
The retaining clips, the ******* clips. Be careful getting them off, I broke an injector by using too much force.
Getting the clips back on is actually pretty simple.
Install the injectors into the rails and wipe some motor oil on the rubber seals first.
Then install the retainer rings (u-shaped). I used the same Knipex wrench listed below for this.
Flat side of the U goes towards the rail and look closely at the injectors and you'll see how it has to align. It can only go one way.
You don't need any special $300 GM tools.
Get a big adjustable wrench (I used a knipex 8603300 I already had).
The shorter side of the clip sits just under the injector electrical connector.
Start it by hand and get the big wrench so you can put some force on the fuel rail and clip to drive it in. I was only able to get it part way on the first squeeze, and then adjusted the wrench. Did it again and then usually had to give a small tap with a flathead to get the different pieces to line up in the clip.
When reinstalling the rails, install the driver side first and bolt it down. Then remove the bolts, they will get in the way of installing the passenger rail.
Passenger rail needs to come in from the rear, not the front.
And here are all the resources that helped me. Keep in mind many of them say to do things a different way, but above is what worked best for me.
Got the car out for a drive and log today... no more misfires! The engine even idles better now, so there was definitely something wrong with a couple of my injectors.
I'm going to go ahead and walnut blast my valves because they are still nasty looking even after using a shotgun bore brush.
Well... I was able to sort out and verify a few more things in HPTuners before I rip the garbage e39 and HPTuners out of the car once and for all in the coming days.
The cam phasing is indeed 180 deg backwards. If you retard the intake cam in HPT, it will advance the cam on the engine.
I also figured out how to kill DFCO completely finally
I also found the table that was preventing me from retarding the timing on a shift...because who doesn't like shooting flames on a redline shift!
If you want the lowdown just shoot me a text brother. If others are interested, I'd be happy to do a quick write up for ya.
You rock and thank you as always! Without your help this car would be almost undriveable.
Originally Posted by griff
Well... I was able to sort out and verify a few more things in HPTuners before I rip the garbage e39 and HPTuners out of the car once and for all in the coming days.
The cam phasing is indeed 180 deg backwards. If you retard the intake cam in HPT, it will advance the cam on the engine.
I also figured out how to kill DFCO completely finally
I also found the table that was preventing me from retarding the timing on a shift...because who doesn't like shooting flames on a redline shift!
If you want the lowdown just shoot me a text brother. If others are interested, I'd be happy to do a quick write up for ya.
Few updates... took a bunch of pics for a couple people requesting to see more of how I cut the oem alternator bracket to fit on the driver side. Also, walnut blasted all the valves and they look brand new now. Amazing they were still pretty gunky after cleaning them prior, but just used carb cleaner and a shotgun bore brush. Lastly, I think I may have found the root to my misfire issues (hopefully). At the upper front of the intake manifold is a twist on connector for a vacuum line. If you don't press it down hard enough while installing it, it will go on fine but just slightly butt up against the lip it is supposed to go under. Never even noticed this before, but be 100% sure you press down on it with a little force to be sure the connector seats under the lips (pics below). Mine was not seated all the way.
Good followed by bad for the intake connector.
My engine came from a car that was hit in the front end. Don't mind the broken bolt hole in the images, that doesn't matter for the alternator mount.
04-17-2020, 03:43 PM
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