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I am looking at getting a GXP and will need some extra juice. I have had a Procharger boosted FI C5 Vette and currently a Caddy CTS V with a Magnacharger. Both are aftermarket systems so the only tuning is with the HP Tuners. I assumed the GMPP was just a canned tune. Does this actually make permanent changes which cannot be done with HPT or EFI Live?

I am not looking at building a race car, but am just thinking about the order of mods. Intercooler, some exhaust work and increased boost is what I am thinking. I don't know how much safe boost the stock turbo is good for, but I don't want to add meth or anything. thanks for any responses.
 

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Hey Nuck,

From my understanding the only reason to go with a GMPP tune instead of an aftermarket one is to maintain your warranty. I personally have the GMPP tune because my car only has 11k on it. If you don't care about the factory power train warranty, my guess is you don't because of the mods on your vette and caddy, I would get your GXP dyno tuned.

My friend just dynoed his Sky Redline with the GMPP upgrade and it 242hp / 232 tq (at the rear wheels.)
 

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The only thing the gmpp tune does that hptuners can't do(efi live doesn't support the gxp) is add the no lift to shift feature, everything else can be changed with hptuners including scaling to the 3bar gmpp map sensors which at $20 a piece everyone should get. I wouldn't go past 25psi with the stock turbo, it usually dips to 20psi near the redline anyway.
 

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Discussion Starter #5
It sounds like you know what you are doing with HPTuners, so you should be able to see plenty of improvement with tuning. You can add the GMPP tune with HPTuners, if you want somewhere simple to start while still getting more power.

http://www.solsticeforum.com/forum/f63/gmpp-turbo-upgrade-19212670-sub-100-a-60589/
No I have never used it myself Josh. It is the favorite toy of the guys who dyno tune my vehicles so it is something I have come to rely on. I am thinking I would just install the mod pieces and then a one and done on the dyno.

My experience with turbos is on Dodge Stealths back in the 90s so forgive my rustic comments. We had to add external hardware to increase boost (electronic valve controller), upgrade injectors and fuel pump just the max out the puny turbos (which turned into heat pumps above 16psi), add a downpipe, BOV, and gut the cats, and of course CAI and catbacks did absolutely nothing.

If you guys can answer a couple more questions that would be great. Is the stock fuel system in the 2.0 sufficient to max out the turbo? What is the main restriction in the exhaust and how can you best eliminate it without sounding like a desperate ricer? I see mentioned a spring swap for the factory BOV. Is that common rather than a complete aftermarket replacement?

Also Shabby mentioned 25psi as a limit on the turbo. What kind of power are you making at that kind of boost? How does the stock clutch hold up after mods? Thanks.
 

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I would not change the spring.
The stock fuel system is fine with the OEM turbo.
The stock exhaust is not that bad GM did a pretty good job.
You could put a high flow cat and improve the system.
With one of the aftermarket tunes you can get between 250RWHP and 289RWHP
Go to E47 and that can go even higher, Vince from Trifecta, Werks, or DDM can help.
 

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Discussion Starter #7
I would not change the spring.
The stock fuel system is fine with the OEM turbo.
The stock exhaust is not that bad GM did a pretty good job.
You could put a high flow cat and improve the system.
With one of the aftermarket tunes you can get between 250RWHP and 289RWHP
Go to E47 and that can go even higher, Vince from Trifecta, Werks, or DDM can help.
I am in Canada so no ethanol to be had. When you say stock fuel system is adequate, would that include with an upgraded wheel in the stock compressor?
 

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Josh,

You fail to include the cost for HP Tuners. You can't do your install without it, so it's really $600 if you buy your own copy, or $300-$350 for someone to tune your car (plus the parts cost of $100) so $400-$450


A larger wheel increases the TQ spike and HP a little but if you are going to do that you Might as well jump up to the 2871 kit from DDM. It retains the exhaust side of the stock turbo but stuffs a Garrett 2871 into it.

That aside sticking with the stock turbo, adding a hi flo cat and retuning will be the best bang for your buck. You will see roughly 300 wheel hp which is a size able jump in power especially for the cost.
 

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Only thing I'll add is CED offers a plug and play GMPP harness, assume all others splice their set-ups into the OEM harness?
 

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Those are slick. I bought a set for a friend and shipped them across the pond.
I wish I had them on mine.
 

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Josh,

You fail to include the cost for HP Tuners. You can't do your install without it, so it's really $600 if you buy your own copy, or $300-$350 for someone to tune your car (plus the parts cost of $100) so $400-$450
True, it is written with the understanding that someone already has HPTuners, like I did as well as the OP. I am not sure about your costs, though; HPTuners is $500 with 8 credits, and unlocking a car only takes $100 for two credits. If someone with a 2009 wanted it done I would do it for them, and would think there are other people out there willing to help out as well.

Only thing I'll add is CED offers a plug and play GMPP harness, assume all others splice their set-ups into the OEM harness?
Very true. I probably would have went that route if it was available when I did mine. However I do like the factory look of adding in the connector the way I did too.
 

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$100 [Hardware costs you Provide] + $500[HP Tuners Standard Suite] = $600

Not sure where the question is.
 

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Discussion Starter #13
Josh,

You fail to include the cost for HP Tuners. You can't do your install without it, so it's really $600 if you buy your own copy, or $300-$350 for someone to tune your car (plus the parts cost of $100) so $400-$450


A larger wheel increases the TQ spike and HP a little but if you are going to do that you Might as well jump up to the 2871 kit from DDM. It retains the exhaust side of the stock turbo but stuffs a Garrett 2871 into it.

That aside sticking with the stock turbo, adding a hi flo cat and retuning will be the best bang for your buck. You will see roughly 300 wheel hp which is a size able jump in power especially for the cost.
Yes the DDM turbo is not much more than the wheel alone. I am used to buying these things in pairs the cost is pretty attractive, especially if I don't have to upsize the fuel system.

If I could tune it to run on pump gas with no injection, and make around 350 at the wheels that is pretty much my old Z06 but a bit lighter. So with the 2871, a big i/c, and a high flow cat, how much boost can you run before you need more injector? The DDM site seems to imply its a drop in but requires a BOV and aftermarket charge tubes. Are people actually making 350RWHP on the stock injectors and pump?
 

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We sure are.
I am hitting a Dyno on Saturday. I am pushing 45lbs/min of air at the high end. I am hoping that translates into a 3 digit HP number that begins with a 4. Even 401 would be cool.
Here is Millers Dyno.
 

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I got the Westers Race tune with no other mods and it is more than enough power. Lyndon was amazing in the process and it has worked flawlessly.
 

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That is miller's not mine. It is at 25PSI

The 2871 has a really nice powerband in the RPM range you spend the most time in
 

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I got the Westers Race tune with no other mods and it is more than enough power. Lyndon was amazing in the process and it has worked flawlessly.
And he's in Canada (AB) for those that it might matter to. He tuned my car at the last PNW Regionals, and holy crap...u guesstimating 300+ HP and 400+ lb-ft (based on past dynos he's done on Sols, estimated drivetrain losses and the fact that he's actually made ADVANCES since those dynos)
 

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elff,
looking at Raw numbers it should be good for 405.
 
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