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3.6L DI CTS power mod discussion

58K views 72 replies 25 participants last post by  tinman 
#1 ·
OK, so it seems the 3.6DI engine aftermarket is still pretty tiny. I'm surprised by this seeing how it's the same engine as in the new Camaro's with only a PCM change, and there are already a bunch of turbo and supercharger options for the Camaro's.

I was hoping to have a little technical discussion on the possibilities of this engine...

I saw the usual intake and exhaust route, and the 30whp gain. Not baddd, but I'd rather not mod my exhaust and make my super nice quiet car super loud for no reason if not needed now. Something to think about though. Doesn't seem to be conclusive evidence of the exhaust systems fitting the AWD model though except for the GMPP exhaust. Boggles my mind though, as what doesn't fit and why? I simply can't see GM (Corsa? or whomever made it) making their exhaust fit differently than others...

So to start.. I believe I read that this engine has a forged crank and rods, and I believe forged pistons (anyone clarify). That means it should take a real beating. Anyone run some decent sized nitrous shots yet? Forced induction should be possible pending tuning solutions.

Direct injection should give a nice fuel window for mods, especially if any tuning solution can up the pressure like is done on other cars.

AWD. Anyone know how much power/torque the AWD system, trans, diff's can handle? Can they take 400-500+whp?

Tuning: This is a big one... HP Tuners has basically told me they won't ever support the 2nd gens since GM has made so many PCM changes over the years on this engine. That is a bit harsh, but it's the truth. Make me sad because I have HPT. Trifecta does a tune, but Vince admitted it doesn't do a whole lot. Shift point tuning could help though as well. Trifecta could probably do custom stuff and datalogging if needed. Does EFI Live offer any support yet? Other ideas?

D3 has the proposed supercharger kit, but it's a bit lofty in price at over $10K i believe. Once could save a little more and buy a V... If the price were closer to $5K, I'd certainly consider... There are several TVS blowers as well as other options that could be retrofit to out application once an intake manifold is designed, drive system, etc. There are also lots of other blowers that could possibly be re-purposed for cheap. Items such as the Eaton M90 or other larger displacement roots style blowers? What about ProCharger's or other 'easier-to-mount' centri blowers? This higher revving 6 could be a total beast...

Turbos: I haven't seen anything suggested, but a custom turbo setup would always work. Even something like a STS remote mount turbo should work... Think Buick T Type V6 turbo goodness!

Anything exotic? Valve springs to rev higher? Cams?

Soo guys, what's the ideas? I'd like to try and brainstorm some stuff and see what all is possible.
 
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#4 ·
D3 has some dyno sheets which show the 30+whp gain from an intake and exhaust. That is a very possible gain if the engine is heavily restricted from the factory. In dealing with forced induction setups like I am used to, I have seen 60+whp out of a conservative tune, as GM tunes tend to run very rich for safety. Why do you doubt the gain so much? Your vehicle listing shows a D3 intake and Magnaflow exhaust, did the pieces not make a difference to you? Not insulting you, just trying to learn more about this platform and the possible mods. If the exhaust sucks that bad, I'll certainly save my money!

I saw the spec sheet for the tranny. The problem with that is that GM trans are rated low, and are rated in torque, not horsepower (HP isn't 'real'). To err on the side of safety the trans may be rated for 300 something, but would likely not break until 450+ something. It is a way to keep warranty claims to a minimum. I find it a bit hard to imagine the trans not taking much more than the car came with stock, although weirder things have happened... Auto tranny's can usually also hold more power than sticks depending lots of variables of course.

For examply the Cobalt SS is a front wheel drive car in supercharged or turbocharged varient depending on year. The newer ones are a direct injected 2.0L with 260hp and 260trq AKA the 4 banger in that light car has as much torque as our 3.6L V6. FWD means weak trans and axles in general, yet the turbo SS's can achieve 330+whp with a simple tune and an intake. More supporting mods yields even greater power. People are even turbo swapping them and pushing power well above 400-500whp and still not constantly grenading transaxles. These cars however have a mucchhhhhhh larger aftermarket as they are 'tuner' cars.

I would certainly like to think that for the money these Cadillacs cost that the quality would at least be on par if certainly not better than GM's econobox. I understand that the CTS will never be the V unless it's a V, however there is no reason we can't a enjoy a bit more power to close the gap. Look at Buick Grand Nationals and other powerful V6's that have been modded for years...

Besides D3 and KPE, does anyone know of any vendors that have pushed this platform at all? It's always nice when a company plays with their own money first and markets some nice products for sale.

That being said however the lack of HP Tuners support or a good tuning solution is likely the Achilles' Heal of these engine ever making good power. I'd say there is a reasonable amount of power and driveability available just in the tune alone...
 
#8 ·
That being said however the lack of HP Tuners support or a good tuning solution is likely the Achilles' Heal of these engine ever making good power. I'd say there is a reasonable amount of power and driveability available just in the tune alone...
I think I read on the camaro forum saying that the tune for the DI engine only got them like 6 hp, something stupidly low.

Also, don't forget, GM made the cobalt SS specifically for the rice burner tuners. Those guys may get 400+hp, but do they have enough traction to make all that work? I'm sure they rate the transmissions where they feel they can safely run all the time. If you are bolting on an aftermarket supercharger, they probably not going to honor the warranty when the tranny fails, so the specs are mostly for GM internally.

I don't think the designers were thinking about the tuner market for the regular CTS. D3 kills everybody on price because people that buy cadillacs usually have the money and don't care about the cost. The normal tuner market for v-6 cars are 30 year old dudes who drive used accords. The main tuner market for people that drive cadillacs, are going to demand a V8. Now this may change as government regulations change, but I'm going to guess to meet economy standards, most future engines are going be turbo 6's with little room for tuning gains.

Personally, I want somebody to take the drivetrain out of a G8 GXP and put it in the caddy. That's the setup we should have anyway.
 
#5 ·
There are no real tuners for the engine available. The intake + exhaust give a peak hp of maybe, and I stress maybe 10-15hp. The stock exhaust isn't very restrictive as it is. There's no turbo to blow here. The intake is actually very well designed as well. Cadillac did quite a bit of engineering on their stuff. The biggest gain would be the long tube headers for the Camaro, if they even fit (they don't from what I hear).

This is a N/A engine, with direct injection. There isn't much more to be wrung out of it because the very restrictive ECU. If the engine had a turbo, a simple tune would net 50+hp, but it does not. Trust me, this isn't a tuner car, nor will it ever be. The biggest thing will be the D3 supercharger, dyno'd at 131hp increase, which will be nice.

The reason forced induction is so hard is because a) no tune and b) we can't do much with the injectors. They're not swappable. Please do a search on the forums, many many people have discussed this. There is VERY little you can do to a CTS.
 
#7 ·
Thanks for the input. I understand exactly what you are saying. This isn't my first rodeo with modding cars. I know there has been past talk about this platform, I was simply hoping to spark some new ideas and discussion.

I know what you mean with the peak output from the intake and exhaust. Overall though it would be nice to have this heavy car closer to 304whp than it's 304bhp.

Obviously some tuning is available as Trifecta Performance can tune the PCM (Vince uses his own custom software), as can KPE using whatever they use. I was reallllllyyyy hoping for HP Tuners support as I own HP Tuners Pro. It would have been nice to adjust the timing and shift points a bit to make the car feel more responsive. But alas...

I understand the whole Cadillac not being a tuner car with the exception of the V series. Since this is the same engine as the Camaro V6, I was hoping there might be some more development in engine mods. The D3 supercharger for instance is mearly a ProCharger setup. I emailed ProCharger about a kit, but they said they could only do a universal kit for our platform. A custom STS turbo setup would also be a good choice. Trifecta would be willing to do the custom tuning I am sure. I don't know the engineering specs on the direct injection, but normally the injection window is more than enough on DI engines. The PCM regulates fuel pressure using the engine driven fuel pump, so it is a trivial task to raise the fuel pressure, and hence get more flow with a software (tune) mod.

Overall, it would simply come down to someone wanting to put up the money to try these parts and advance the platform. I know that often times companies will do some R&D to try and improve upon their own products. So far the only companies I have found that have anything decent is D3 and KPE. Am I missing anything here?

Thanks everyone for your replies! I know there is no magic pixie dust to make power, however every little bit helps. I was hoping someone might have an idea or lead to look into. I suppose for now I will be happy with my intake lol.
 
#11 ·
Ohh, I didn't know that one. Sounds like they went the same route as HP Tuners or were trying to use a solution from HPT when they dropped the project. It's sad because GM did use I believe about 6 difference PCMs on this same engine. I would think that HPT or someone else could at least develop the tuning for a couple of the more popular ones. The PCM's themselves aren't much different on the software level (if at all), the problem is the data read/write access methods change for each PCM so it makes the work that goes into coding that much more difficult. HPT claims it just isn't worth it to them. Vince of Trifecta does all his own work mapping out the PCMs so it looks like right now he is just about the only one who will touch this engine. Still not sure if the tune is worth the $400 his price or $300 Trifecta dealer price for a canned tune.
 
#16 ·
The tune as stated above is really not worth a whole lot of power, maybe 5-10whp. I have never spoken to someone who has actually gotten the tune however, so the driveability and low end power may make the car feel much different.

As fas as a CAI is concerned, I recently purchased the KPE CAI, and it is very nice. I didn't notice much of a power increase, but the extra sound and throttle response is decent. I have an AWD car and it seems that most if not all of the aftermarket bolt on exhaust system won't fit because of interference with the front transfer case. I'm also not sure how thrilled I am to make the nice quiet luxury car, a bit loud and obnoxious. It just certainly won't sound as nice as the TVS blown V8 of the CTS-V!
 
#17 ·
Thanks for the link. Here is the reply from Vince.
Hi John,



On a 2010 Camaro V6 with the same engine we gained 23HP and 17TQ at the wheels with a tune. Yes, we can ship via USPS to Canada, and the price is $435 shipping (using the EZ Flash cable), plus an additional security deposit of $200 which is refunded when you return the equipment.

That seems a little rich but I think the improved driveability will be quite noticeable. I will have some more emails for Vince.

I have Magnaflows on my Supercharged '06 Eclipse with 3" pipe. Sounds freakin awesome.
 
#18 ·
Glad Vince got back to you. Only problem is that a Camaro has a different intake and I'm sure a much less restrictive exhaust. It is certainly not the exact same setup. That right there could account for a good portion of the power. I've heard before that the real gains are somewhere around 10hp max. It is unfortunate, but with an intake, exhaust, and tune, you likely still wont crack 300 wheel HP.

Ya, that Magnaflows sound decent, I had a 3" setup on a supercharged Cobalt SS that was nice.
 
#21 ·
Thanks for reposting those specs.

Honesly the trans wouldn't be a huge concern of mine. As long as you weren't constantly beating on it I would imagine it would survive just fine under some decent power.

Think about the ratings... That rating is what GM is willing to warrant for many many miles, and have the lowest amount of warranty claims... It is certainly under-rated by a sizeable safety factor.

I have talked to people who work for pinion/rear-end/trans companies and the testing that some/most units undergo is a max torque load type of test that would be equivalent to neutral dropping a tranny repeatedly over and over again. Most units survive this test hundreds of times before failure. If an OEM specs out that a unit has to pass 100 tests, many units will exceen 400+ tests which would be a huge safety margin.

Don't get me wrong, hopping up the power and then beating on the car will certainly shorten the life of many components, I just don't see the trans being a terrible problem with this car. I could be entirely wrong, but I've never seen any hard evidence of a trans/diff/transfer case problem. The only bad thing is that the AWD system might not be as strong as a RWD CTS.
 
#22 ·
Ya, I don't see many tranny problems with the low power/torque increases we may find out there in the after market community.
Here are my last emails with Vince.

Hi Vince

On the Cadillac forum people say that the camaro has better intake & exhaust thus the 23hp gain & that the Cadillac 3.6 DI will only get maybe a 10 hp gain. Have you tuned a Cadillac 3.6 DI engine?

Thanks

John

Reply-
Yes, we’ve tuned them remotely but I don’t have any dyno results.

The 23HP gain on the Camaro was due to fuel ratio optimizations. Every car will vary, some will gain more than others but it has absolutely nothing to do with the intake and exhaust system. Not that’s it is a apples to apples comparison, but I did a 2006 CTS-V on the dyno, with the LS2 and it gained *45* HP with a tune. I’ve tuned plenty of LS2 Corvettes and none of them came close to that kind of gain. The notion that the Cadillac would somehow get less of a gain from tuning because of differences between it and the Camaro makes no sense at all.



- Vince Geglia

Trifecta Performance, Inc.

He sounds sure of his tunes.:hmm:
 
#33 ·
but I did a 2006 CTS-V on the dyno, with the LS2 and it gained *45* HP with a tune.
Sorry I am late to this party.

I don't think I would listen to this guy. I have spent the last 4 years hanging out in the V forum, and anyone who got that much with a tune, killed their drive-ability. And I mean, murdered it, dead. Of course most V and Corvette guys don't care about drive-ability, they just want fast.


I don't think you are ever going to get much support for this engine. It's a "high feature" engine, meaning high cost, meaning most applications for this engine are into cars not likely to be modded. In the case of the Camaro, almost no one is going to mod an LT, else they would have bought the SS. (although I have seen some guys in the Camaro forums pining for a REAL supercharger kit)

And as a Camaro LT owner, I can tell you, the stock exhaust is very loud, and very raspy. Not like an aftermarket exhaust mind you, but it is probably the loudest factory exhaust I have heard.

I don't see any gains from an aftermarket exhaust. On a side note, Corsa has a catback for this engine (custom fit to the Camaro anyway) that makes it sound almost like a small V8, if sound is what you are after.
 
#23 ·
^ No offense, but Vince is trying to sell a tuning solution, so he will tell you just about anything... Not that he isn't a good guy, it's just the logic isn't there. To gain that kind of power from a tune with no other mods is a bit of the stretch of the imagination. Vince himself admitted that there was very little power gains on this engine. He said this on one of the Camaro forums I believe. If I ever see the post again I'll post it up.

The comparison is pretty bad... The CTS-V has a TVS blower sitting on a V8, and will gain almost that much power from a simple cold air intake *without* a tune... Other mods really open up that car. Comparing a forced induction engine is not even close to that of a naturally aspirated engine.

I would be optimistic about power mods for this car, but I'm being realistic. Without forced induction there is little power to be had. With intake and exhaust and a tune you'd be lucky to see wheel HP that matched the rated stock brake HP. Drivetrain losses are bad and the car sees something like 260 wheel horsepower stock. It's a bit of a stretch to think an intake, exhaust, and tune would give 40 wheel horsepower.
 
#26 ·
Thanks for the continued discussion with Vince.

That Camaro link was a decent read. I do recall however reading a thread somewhere where Vince himself had commented that the LLT in the CTS didn't have a very big gain. I could be completely wrong? I'll try and find it somewhere...

The base engine is the same, however other factors could come into play which could make for less of a gain in the CTS versus the Camaro.

I would certainly be curious to see a before and after dyno on a stock and Trifecta tuned 3.6 CTS. I'll stay slightly optimistic for now lol.
 
#34 ·
Good of you to chime in.
From Camaro LT to SS there really isn't that much of a price jump as opposed to the CTS jump to the CTS-V.
I've resigned that there isn't much that can be done to this engine other than CAI & maybe a custom cat back exhaust (AWD). I would love to see a CTS on a dyno before & after Vince's tune though! :want: LOL
 
#35 ·
Yessir, that is about what I've decided on as well. So far I'm happy enough with the CAI. It doesn't do much, but a tiny bit. I doubt I'll mess with the exhaust on this car. The CAI opens it up a little, and I don't want loud or raspy. This car is too nice to mod much. I may still get a tune though. There won't be a before/after dyno, but I can at least tell you what the butt dyno feels.
 
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