Rauq's Twincharged LSJ in SC - #240 - GOBZILA

[Rauq]

I repolled parameters and still don't see anything that I think could or should be SCIP.

What I'm thinking of doing now is pulling the PCM pin for SCIP input and sticking it in the Fuel Tank Pressure slot. I can log that PID (it comes up as 0v all the time) and will map it for SCIP in HP Tuners. As far as I can tell that slot on C1 should be empty on an '06 LSJ. I don't think it'll cause a CEL or other symptom seeing erratic readings there, and if it did, I would imagine it would only cause an EVAP related CEL which is already squared away. Diagrams are given below, mostly for my own future reference.

My major interest in logging SCIP is that I should be able to tell how much, if any, I'm compounding boost with the twincharged setup. I expect it to compound under 15psi which is where the supercharger bypass should be fully open. The SCIP should basically be turbo-only boost and the MAP is post-supercharger boost. Unfortunately as far as I can tell the AEM Tru Boost controller doesn't have an analog output for boost level, so this is my next most creative solution.

 

[Gtstorey]

Hopefully the Pin 24 is actually connected on the ECM board. I would confirm by adding voltage to see if it changes before doing a lot of other work.

If you have a prolink version of HPT, you could also use that, or even a serial connection like the original way of tying in a wideband.

 

[Rauq]

Met up with @MX184 last night at Greer Dragway for the first event of Carolina Dragweek!

I made a pass here in Oct 2021 (7.8@88mph, completely stock LSJ and F35) and they told me I was too fast for the way the car was built, and that I needed arm restraints (which I was wearing). They didn't want to talk to me about it then, which I understand, as the track was hot, and my reading of the rules is only worth so much.

They told me again this time they'd let me make one pass but they didn't like the way my car was put together. The track official told me even if I had the full cage "like the other buggy" that I still wouldn't be safe because my car "wasn't built right," despite the fact that at that point they'd be the same car... oh well, pick your battles.

Quick rundown of the setup, I'm running an unopened LSJ with a 2.9" pulley and an S257, with a 3.84 LSD F23. 225/45R17 Falken RT615K+ closer to the end of their life than the beginning. I have a 6lb spring in the wastegate, but no way at the moment to verify turbo boost levels. The supercharger bypass should be completely open around 15psi in the intake manifold and completely closed around 10psi according to my almost scientific regulator tuning. I'd guess I'm somewhere in the mid-upper 200s in whp right now.

I ran a 7.6@87mph with a 1.7s 60'. I'm pleased with the two tenths and amused by the mph. In my last outing, it didn't spin a bit except for a chirp at the launch and each shift, and I finished near the top of third. This time around, it pulled so hard through first that I thought I'd blown the tire off. I bumped the limiter at the top of first for 0.2s; according to my HPT log, I hit 60mph at 3.3s into the run. I also became intimate with the limiter at the top of 3rd. Even when accounting for the different final drive between my old F35 and the new F23 (4.05 vs 3.84), I've got 8mph less in 3rd gear I was not thinking about that, or the fact that I'd probably be faster sooner in the run than my last outing. Most notably, my peak speed during the run was 100mph at about 7.1 seconds in. Yes, I managed to fumble 13mph between bumping the limiter and trying and failing to make the 3-4 shift. That was completely on me, I can do the 3-4 all day when I'm expecting it. The vertical white line in my log is right at 7.6s after I started moving off the line.

If it wasn't 80° out then it was mid 70s. Post-turbo IATs were right at 100 for the whole run, and post-supercharger IATs were right at 120. Idling in the pits probably didn't help but those are also about the IATs I see when I'm beating on the car while tuning. Peak MAF frequency was 8400Hz. It's a stock LSJ MAF in a 4" housing. I'm hoping to be able to put down power at the same boost with the turbo turned up (and the supercharger bypassed more). I do hope to be able to turn the turbo up to about 24psi, which my four-function calculator math says should put me a bit under 11,000Hz, which I believe is doable.

All in all, I'm happy with the outing and where the car's at now. Just a bit more fine adjustment in the tune and I'll be ready to install the boost controller and a stiffer wg spring. I see some 245 wide RT615K+ in my future as well.

 

[MX184]

Good to meet you yesterday! Weird that they had a problem with your car and not mine. It is what it is I guess. Love the twin charger setup, super unique!

 

[chief404]

what model turbosmart actuator are you using?

 

[Ross]

How is tuning going for your twin charged LSJ? I was hoping you would post the tune, as one day I want to be twin charged too.

 

[Rauq]

What I'm thinking of doing now is pulling the PCM pin for SCIP input and sticking it in the Fuel Tank Pressure slot. I can log that PID (it comes up as 0v all the time) and will map it for SCIP in HP Tuners. As far as I can tell that slot on C1 should be empty on an '06 LSJ. I don't think it'll cause a CEL or other symptom seeing erratic readings there, and if it did, I would imagine it would only cause an EVAP related CEL which is already squared away. Diagrams are given below, mostly for my own future reference.

My major interest in logging SCIP is that I should be able to tell how much, if any, I'm compounding boost with the twincharged setup. I expect it to compound under 15psi which is where the supercharger bypass should be fully open. The SCIP should basically be turbo-only boost and the MAP is post-supercharger boost. Unfortunately as far as I can tell the AEM Tru Boost controller doesn't have an analog output for boost level, so this is my next most creative solution.

View attachment 40318
View attachment 40319

Hopefully the Pin 24 is actually connected on the ECM board. I would confirm by adding voltage to see if it changes before doing a lot of other work.

If you have a prolink version of HPT, you could also use that, or even a serial connection like the original way of tying in a wideband.

Just wanted to follow and confirm this does work. Still working on some demonstrative data logs to show pre- and post-supercharger boost levels. I also added a phenolic intake manifold spacer and want to see if I can show benefits there under boost. The challenge in quantifying this is that the baseline IAT2s are now significantly lower than they were before.

I'm thinking that if I ever needed to pull another data point into the ECM, I'd do it through the barometric sensor, given that at this point I've completely spoiled the ECM's BARO-SCIP-MAP correlation routines. Probably not recommended for any LSJ's only running superchargers, though.

 

[Rauq]

Looking for some general input- I've looked at a couple track days at tracks that have noise limits. Regardless of what the dB level is and where the microphones are at, I doubt an open wastegate and open turbo dump are going to cut it.

I'm looking for some general input from folks with some actual experience in good bang-for-the-buck sound management in this regard. I've thought about putting a 1.5" inlet powersports muffler on the wastegate and a 3" muffler on the turbo, potentially with provisions to point the outlets at one side or the other depending on the track. I'm not trying to become silent or fab a crazy merge or anything. I can afford to lose a few ponies but would rather not lose any boost control. The rear-mounted A2A will require some packaging considerations.

As it is, I'd say the exhaust with the wastegate closed isn't that bad. Baseline volume is substantial, but it doesn't get much louder with load. I wouldn't be surprised if there's stock V8 exhausts out there that are louder under load. The wastegate, though... is loud.

Pic for reference:

 

[Rttoys]

Look in the motorcycle and side by side world. They have to meet sound regulations like regular automobile, but they have a much more compact area to work with, like we do. Everyone pulls the stock exhaust off for loud aftermarket exhausts. This means the stock stuff is sitting in thier garage collecting dust and being kicked around, so it sells pretty cheap, if not free.

 

[Rauq]

In-car playlist of all 4 runs:

https://youtube.com/playlist?list=PLIz0bmJum5mjaf-RAqgI7SMyIGd6XA0gn

Spectator view of run 4:

 

[Rttoys]

Man, that’s a small and tight course.

 

[Rauq]

Man, that’s a small and tight course.

That's all we have access to on campus, but makes the Goblin pretty much a cheat code among street legal cars. There were a couple actual karts and the FSAE car as well. Events are super laid back and cheap. Classes are typically stock/not stock each of FWD, RWD, AWD, and Miata.

 

[Rttoys]

The goblin has a definite advantage there.

 

[mike_sno]

Update on my F23 swap:

I've been through 5 tanks of fuel on my F23 swap and consider it generally wrapped up. I think it was well worth the effort.

I bought a junkyard 3.84 final drive F23 from a Cobalt for $200 with 60k miles on it back in November of last year. I also ordered F23 transmission mounts from DF before they were added to the store. They're available now, but you might have to contact DFKC to get just the front trans mount (the rear is the same between F23/F35), and to get the F23 shifter cable bracket.

For an LSJ, the swap requires a base model thermostat housing, as the LSJ one interferes with the shifter cable bracket mount on the F23 transmission. While the base model and turbo thermostat housings are nearly identical, you will need the base model thermostat housing- the turbo one has an additional threaded hole for the turbo coolant feed line. Both will have a threaded hole for a temp sensor (LSJ is the only one with a sensor in the head). You can plug that hole with a BMW oil drain plug. You will also have to re-plumb the coolant lines that go to the oil cooler. To pipe them like the LNF, you will need a 3/4" hose tee to splice the oil cooler return into the expansion tank line, and a 1 1/4" hose tee to splice into the radiator incoming line.

Besides that, the hardware is otherwise pretty straightforward and has been well documented. If you're starting with an LSJ, you only need base model axles, and they'll go straight into LSJ wheel hubs. The clutch and pressure plate don't care which transmission they're hooked up to. My F35 slave cylinder was good, and I've read you can make it work, but I just installed a new F23 slave cylinder. The Goblin hard line required a little bit of bending, but the bleeder is now in a much easier place to reach. I did have to buy a new base model Cobalt clutch pipe (12582665) for the bleeder elbow. I broke mine trying to get a bleeder unstuck but can't remember if that was just me being stubborn or what.

I swapped to the new DF shifter at the same time as the trans swap so I don't really have an apples-to-apples comparison, but the new trans does seem to shift easier at high RPMs than the F35 did.

I also installed an OBX LSD as part of my swap. I didn't expect Quaife quality, but I'm happy with it so far. I picked up a replacement hardware kit from this dude and flipped the helical gears as they were backwards. But I was able to get that diff in a week for $400, rather than a long delivery date from overseas and $1xxxx for the Quaife. The diff swap is real easy (aside from pulling the case races) if you can 3d print an input shaft spline to socket adapter. I can elaborate on that if need be. I did a fluid change after putting about 500 miles on the swap and the fluid looked good, so I don't have any reason to believe anything's not working as it should. It spins both tires from a dig and will not one-wheel peel in a turn, although I've never driven a non-LSD Goblin for comparison.

I also think the gearing is a little better in the F23. The RPM drop on a flat out 1-2 shift is about 500 rpms shorter on an F23 versus the F35 (for reference, the F40 has a similar 1-2 RPM drop as the F35, and only has a shorter RPM drop than the F23 and F35 on the 3-4 and 4-5 shifts). Second gear is a bit shorter in the F23 versus the F35. If you're starting with an LSJ 4.05 final drive F35, you'll cruise about 150 rpms lower at highway speed. Folks have talked about the HHR 4.17 final drive F23, but in my mind that's really only a big deal if you're running tires taller than 25" (which is Cobalt size).

I started with the bees knees 4.05 LSD/G85 F35 and expect to be able to sell it for much more than the cost of my swap, and if I ever manage to pop this F23 (unlikely, as I understand it's actually a stronger trans) then I should be able to pick another up for a couple hundred bucks. Between LKQ and www.car-part.com it looks like there's at least a couple dozen replacements within 50 miles of me.

I try to figure out what the right pluming is for the LSJ. I have a ton of hoses with my engine, but can't find anywhere a decent picture on how to do it best. Do you have a good picture from your engine where you can see the pluming?

Is there no way I can keep the LSJ thermostat housing with the F23 gearbox?

 

[Rauq]

This is the best photo I can find. You can see the two tees for the oil cooler, one into the main radiator return line and one into the hose that goes to the expansion tank. This is roughly how the LNF is set up, the main difference being that the LNF oil cooler has its coolant barbs clocked differently. You'll want to double check that you're flowing coolant through the oil cooler in the correct direction, opposite the flow of oil to maximize the fluid temperature differential.

You can see in this photo just how close the base model thermostat housing comes to the shifter cable bracket boss. The LSJ thermostat would require some decent grinding on the trans which might compromise if not eliminate this mounting point.

Compare to the *much* more protruding LSJ thermostat housing.

 

[Bajakid1450]

In-car playlist of all 4 runs:

https://youtube.com/playlist?list=PLIz0bmJum5mjaf-RAqgI7SMyIGd6XA0gn

Spectator view of run 4:

Look up on Google DDMWORKS Atom 700 they are the ones that did my goblins engine and turbo setup, they twin charged a atom with a lsj and got 700hp that is usable and quiet enough to pass noise regulations

 

[Rauq]

I know of them; Dave and I have a friend in common, and I've been referred over there before. I never did call them up, though, as I've already had my twincharged setup running for a season now, and it works pretty much as planned. I need to put a fuel pump in it to turn it up any higher, at which point the limitation will be the completely stock LSJ.

 

[Rauq]

I was led to believe I'd have a fuel pump bucket with a venturi bucket on the bottom (see the first pic) and ordered a fuel pump accordingly. Turns out that not all Cobalts did, including mine (see the second pic). My bucket has the pre-pump filter on the bottom like in the second pic. In the inside on the bottom is a second filter. There's a spring loaded diaphragm in the bottom of the bucket at the pump inlet that I want to believe isolates the bucket if the outside bottom is not covered in fuel, so the pump pulls fuel through the outside filter when it's submerged and from the bucket through the inside filter when it's not.

I understand folks have had issues starving pumps on other setups (especially on installs with mods like drilling the bucket) but I can't find anything to read about how well the spring diaphragm flows or whether the venturi bucket is the one to have.

I'm unsure whether I should pick up a venturi bucket, exchange the pump for a non-venturi ported one, or do something else.

Any input with experience on these types of buckets is welcome.

 

[mike_sno]

This is the best photo I can find. You can see the two tees for the oil cooler, one into the main radiator return line and one into the hose that goes to the expansion tank. This is roughly how the LNF is set up, the main difference being that the LNF oil cooler has its coolant barbs clocked differently. You'll want to double check that you're flowing coolant through the oil cooler in the correct direction, opposite the flow of oil to maximize the fluid temperature differential.
View attachment 43720

You can see in this photo just how close the base model thermostat housing comes to the shifter cable bracket boss. The LSJ thermostat would require some decent grinding on the trans which might compromise if not eliminate this mounting point.
View attachment 43721

Compare to the *much* more protruding LSJ thermostat housing.
View attachment 43722

Understood. You put the oil cooler parallel to the front radiator. What's the coolant temp like when you hit it hard? I have the oil cooler now directly at the heat exchanger. Hit it a bit today and temperature never came above 184F. I have not really looked at the in and outflow of the oil cooler, I put the hoses on that I have minimal crossings. I have to get an oil temperature sensor to see how well that works.

 

[Rauq]

Understood. You put the oil cooler parallel to the front radiator.

Coolant path to the oil cooler parallel to the coolant path to the radiator? Kind of... I believe the inlet is from the coolant return line from the radiator, and the outlet goes to the overflow tank line. I intended for it to be the same flow path as the LNF oil cooler.

What's the coolant temp like when you hit it hard?

I didn't see over 190°F at Road Atlanta in August.