[JVL]

Hello,

I recently purchased a Mysterious 2008 GXP and have spent the first 2 months of owning it driving it, and reviewing the forums. It has 21,000 miles, garage kept and is in great shape mechanically and cosmetically. It is 100% stock at the moment with the addition of a wind restrictor. I work about a block from ZZPerformance in Michigan and am looking to get their tune. I have a family member that works for GM and supped up an HHR and recommended I get upgraded MAP sensors and a high flow cat downpipe before the tune as those would give me the best bang for buck performance upgrades. He also had a few vehicles tuned by ZZP and was very happy with the cost/results.

I spoke with ZZPerformance today and the gentleman i talked to said that the only upgrades i really need to do before the tune is to get the upgraded MAP sensors and a CAI. He said the tune will be adjusted for the CAI, but everything else can be added on after the fact, and the tune doesnt need to be adjusted. I let him know my plan was to just do the MAP sensors and downpipe upgrade and he said i would be missing out on some power if i didnt do the CAI, and would have to retune if i added the CAI later.

As a little background this is now my daily driver during the summer. I did put new sport tires on it right when i bought it, and plan on doing the DDM brace bundle also. I wont be taking it to the track, but do enjoy spirited driving from time to time.

(added a PDF showing my shopping cart at ZZP for reference) If i did the sensors, CAI, and LNF downpipe w high flow cat, and tune, it be around $1k and should make the car more fun to drive.

From reading prior posts, you all have alot more experience with mods/upgrades and tunes.

For those that have knowledge on these subjects, is the CAI necessary? seems like many say it doesn't add any power, but does it with proper tune? Will the High flow cat add more power than the CAI? or should I do both? I don't want it to be super loud, but i understand both these mods make things a bit more noisy. Thanks for taking the time to read my post and respond.

 

[kgschlosser]

Before you eve step into doing any modifications you should go over the vehicle and replace components that are known to fail because of age and also components that are just simply known to fail around certain mileages.

The timing chain is a biggie that we have seen popping up and the vehicle mileage is all over the board so it's an age thing. If you are doing the timing chain I would recommend to do the water pump as well as these are known to fail with as low a mileage as 35,000
You should also consider replacing hoses and belts because of dry rot.

 

[Steveorama]

Hello,

I recently purchased a Mysterious 2008 GXP and have spent the first 2 months of owning it driving it, and reviewing the forums. It has 21,000 miles, garage kept and is in great shape mechanically and cosmetically. It is 100% stock at the moment with the addition of a wind restrictor. I work about a block from ZZPerformance in Michigan and am looking to get their tune. I have a family member that works for GM and supped up an HHR and recommended I get upgraded MAP sensors and a high flow cat downpipe before the tune as those would give me the best bang for buck performance upgrades. He also had a few vehicles tuned by ZZP and was very happy with the cost/results.

I spoke with ZZPerformance today and the gentleman i talked to said that the only upgrades i really need to do before the tune is to get the upgraded MAP sensors and a CAI. He said the tune will be adjusted for the CAI, but everything else can be added on after the fact, and the tune doesnt need to be adjusted. I let him know my plan was to just do the MAP sensors and downpipe upgrade and he said i would be missing out on some power if i didnt do the CAI, and would have to retune if i added the CAI later.

As a little background this is now my daily driver during the summer. I did put new sport tires on it right when i bought it, and plan on doing the DDM brace bundle also. I wont be taking it to the track, but do enjoy spirited driving from time to time.

(added a PDF showing my shopping cart at ZZP for reference) If i did the sensors, CAI, and LNF downpipe w high flow cat, and tune, it be around $1k and should make the car more fun to drive.

From reading prior posts, you all have alot more experience with mods/upgrades and tunes.

For those that have knowledge on these subjects, is the CAI necessary? seems like many say it doesn't add any power, but does it with proper tune? Will the High flow cat add more power than the CAI? or should I do both? I don't want it to be super loud, but i understand both these mods make things a bit more noisy. Thanks for taking the time to read my post and respond.

I have the ZZP tune I had done by sending in my ECM and I'm pleased with it. They are right about deciding if you want the 3 bar MAP sensors prior to tune, but they don't actually do anything other than measure boost PSI. The stock ones measure to around 21 PSI reliably while the 3 bar ones should be closer to 30. Again they don't provide any performance, but rather provide an accurate measurement of PSI. They do require a retune to be used, hence you need to purchase them before the tune. Some folks use them some don't. It doesn't effect your performance, but just provides peace of mind mostly.

The CAI does almost nothing on our cars just like the charge pipes. It's been well documented over the years, but some still claim around 5-15hp like K&N. It's a a great cosmetic and sound upgrade and that's about it. I added my GMPP CAI after the tune and notice zero difference in performance for the negative or positive. The only really bolt on improvement would be a catless or hi-flow downpipe. That's around another 20 or so HP. After a tune the ECM should be able to adjust to bolt on performances that were otherwise hindered by the stock learn down feature from GM. It retarded the system to 260 lbs of torque after driving around a bit. It's possible the ZZP rep you talked to may be confused with another car in regards to the CAI or is just trying to make a sale, but again on most other cars CAI typically still provide very little performance unless coupled with a replacement exhaust and cat setup.

Their basic canned tune that you can choose some options on is around $200. The 3 bar MAP sensors they sell with pigtails is another $115 and their catless downpipe is another $300. Honestly, that's all you need. The CAI is purely cosmetic and can be added at anytime after the tune. You will notice a dramatic performance enhancement with just the $200 tune if you want to save the money and add other parts later. (minus the 3 bar MAP sensors of course)

 

[JohnWR]

Some CAIs change the airflow enough that the MAF sensor provides different readings. In that case, adjusting the tune to the intake is beneficial. The CAI itself adds nothing.

 

[kgschlosser]

but they don't actually do anything other than measure boost PSI

Not 100% correct. While it is used to show you boost pressure in the Driver Informant it is also used as a double check that the MAF is working properly. Using the charge air temp, barometric pressure the reading from the MAP and also what the throttle position is the ECM is able to put those readings into a table and a range of what the MAF should be reading gets returned. If the MAF is not within those boundaries a DTC gets set. It is also used so the ECM knows if the recirculating valve is functioning properly. It does this by checking what the pressure is in the intake pipe and what the pressure is in the intake manifold. If the recirculating valve is commanded open and the pressure is the same the ECM will set a DTC for a problem with the valve.

Those are 2 other uses off the top of my head.

So if your boost pressure eclipses the limit of the sensor you could have some issues.

 

[kgschlosser]

The thing I do not like about the mail in ECM programming services is that they are not custom. Every vehicle is different even if they roll off the assembly line one after another. Using a "canned" tune is going to make changes that will work across the board on every vehicle It's doesn't maximize what your vehicle is able to do. It is slightly better then the GMPP tune but it has the same basic idea behind it.

 

[Steveorama]

Not 100% correct. While it is used to show you boost pressure in the Driver Informant it is also used as a double check that the MAF is working properly. Using the charge air temp, barometric pressure the reading from the MAP and also what the throttle position is the ECM is able to put those readings into a table and a range of what the MAF should be reading gets returned. If the MAF is not within those boundaries a DTC gets set. It is also used so the ECM knows if the recirculating valve is functioning properly. It does this by checking what the pressure is in the intake pipe and what the pressure is in the intake manifold. If the recirculating valve is commanded open and the pressure is the same the ECM will set a DTC for a problem with the valve.

Those are 2 other uses off the top of my head.

So if your boost pressure eclipses the limit of the sensor you could have some issues.

I understand, it seemed they were being presented to the OP as being somehow performance improving by ZZP though. My point was they don't provide any performance enhancement and you are installing them so that everything is reading properly and ensure everything is functioning properly. A lot of folks operate aftermarket tunes without them and don't seem to have any issues. I'm not sure if those tuners throttle back max boost or not to accommodate the stock sensors, but other than the GMPP stage 1 they all seem to offer a tune that works with the stock setup. From my understanding though, the stock MAP sensors are actually around 2.75 bar vs 2.5 as often stated so the stock ones should still operate to about the 25 PSI threshold which is at the top of most tunes anyway. The debate on whether the 3 bar sensors are necessary will go on for a while and I'm sure GM errored on the side of caution when utilizing them on their stage 1 upgrade. I know when I had mine done I elected to use them since for the same reasoning GM engineers saw to include them so that made sense to me.

The thing I do not like about the mail in ECM programming services is that they are not custom. Every vehicle is different even if they roll off the assembly line one after another. Using a "canned" tune is going to make changes that will work across the board on every vehicle It's doesn't maximize what your vehicle is able to do. It is slightly better then the GMPP tune but it has the same basic idea behind it.

Canned tunes vs "tuning" are really two different things and should be viewed accordingly. Canned tunes are really no different than what GM does with the stock ECMs anyway right? Yes every vehicle would have some slight differences between them off the assembly line, but GM like all of the other manufacturers still program them the same. It's good enough for 95% of the buyers out there. Going to a tuner and doing data pulls on a dyno and road testing is the best way to squeeze every ounce of potential out for your vehicle, but may also not be practical or even necessary for everyone. (Although ZZP like other tuners, does offer that tuning service if you're local) Everyone's needs and wants will vary so it's nice that we have the option of both on our cars. The benefits to a canned tune is they're basically all built off of the GMPP stage 1 tables which at this point has proven to be a very reliable modification. You would assume whatever alterations were made haven't blown up too many cars at the point as they continue to keep using the same formula +/- some minor variations. By raising the parameters to let the vehicle perform better than it did stock, many owners find that sufficient for the price and effort given to meet their needs/wants. However as often stated by Robotech on the Sky forum, canned tunes aren't really tunes anyway. Like tuning an instrument you wouldn't just pick it up and make the same adjustments and expect them all to sound the same. Every instrument needs to be tuned individually and uniquely to have the correct note. So maybe we really shouldn't call them canned tunes, but rather unspecialized application upgrades.

 

[kgschlosser]

Remote tunes can be done as well. The vehicle does not need to be on a dyno and you do not have to be local to a tuner for this service. It's a more expensive service then a canned tune because it will be taylor made to your vehicle and also because you will have to buy special hardware so the tune can be done remotely.

Canned tunes in essence follow the same concept as the factory tunes do. They will work on almost all of the vehicles made (kappas) they are more aggressive then factory tunes but are still well inside of the safety margin in order to be able to be used on all vehicles (kappas). From experience tuners can put together a tune that is a little bit better than a canned tune by you giving them a list of upgrades that you have done to your vehicle. Again it will not be dialed in 100% to get you the most out of it but it will be better than a traditional canned tune.

 

[kgschlosser]

A canned tune is a tune. someone has spent the time to make changes that most vehicles are happy with. It's not specific to your vehicle but it is a tune. Think of a pitch fork being made. A machine makes it and it will be close to be a perfect note. That would be a canned tune. Some companies sell them like that and they are cheaper to buy. Other companies will have a person that manually adjusts the fork to accounting for density changes in the metal or variations in dimensions of the fork They spend the time to dial it in perfect for the properties of that fork.

A canned tune is still a tune it just isn't dialed in for your vehicles properties.

 

[SSolstice]

Hello,

I recently purchased a Mysterious 2008 GXP and have spent the first 2 months of owning it driving it, and reviewing the forums. It has 21,000 miles, garage kept and is in great shape mechanically and cosmetically. It is 100% stock at the moment with the addition of a wind restrictor. I work about a block from ZZPerformance in Michigan and am looking to get their tune. I have a family member that works for GM and supped up an HHR and recommended I get upgraded MAP sensors and a high flow cat downpipe before the tune as those would give me the best bang for buck performance upgrades. He also had a few vehicles tuned by ZZP and was very happy with the cost/results.

I spoke with ZZPerformance today and the gentleman i talked to said that the only upgrades i really need to do before the tune is to get the upgraded MAP sensors and a CAI. He said the tune will be adjusted for the CAI, but everything else can be added on after the fact, and the tune doesnt need to be adjusted. I let him know my plan was to just do the MAP sensors and downpipe upgrade and he said i would be missing out on some power if i didnt do the CAI, and would have to retune if i added the CAI later.

As a little background this is now my daily driver during the summer. I did put new sport tires on it right when i bought it, and plan on doing the DDM brace bundle also. I wont be taking it to the track, but do enjoy spirited driving from time to time.

(added a PDF showing my shopping cart at ZZP for reference) If i did the sensors, CAI, and LNF downpipe w high flow cat, and tune, it be around $1k and should make the car more fun to drive.

From reading prior posts, you all have alot more experience with mods/upgrades and tunes.

For those that have knowledge on these subjects, is the CAI necessary? seems like many say it doesn't add any power, but does it with proper tune? Will the High flow cat add more power than the CAI? or should I do both? I don't want it to be super loud, but i understand both these mods make things a bit more noisy. Thanks for taking the time to read my post and respond.

What are your goals?

Your car is fairly low miles, so if it was run once in while everything should be ok, don’t replace the water as preventive maintenance. Any mechanical part can fail at any time. I would be more worried about the age of the tires, coolant and brake fluid age, engine oil, belts, spark plugs, in other words do a basic tune up.

-If you are not planning to run more than 25 psi of boost, no need to upgrade the map sensors. If you are planning to upgrade the turbo in the future sure get the 3 bar map sensors before the tune.

-The stock Air box is as good as their CAI, if you get one get it right before the tune.

-If you live in emissions free county get a catless downpipe, less exhaust restriction=more power. There are a couple of tables tables that they have to be disable if you are running one, so if you get a catless downpipe get it before the tune Or you can decat your stock downpipe.

In summary if you are not looking to race anyone just get the tune nothing else And do a full tune up.

Do worry about what to monitor during logging let ZZP worry for you. They are the largest ecotec company in the world, they probably know what they are doing lol.

 

[kgschlosser]

I suggest you upgrade the CAC (Charge Air Cooler) if you are going to be running a boost pressure into the 20's. They are not designed to handle that kid of pressure and are not large enough to flow that kind of volume of air. You end up with a large pressure drop from one side of it to the other. Not only do you loose HP from it you also put a lot of stress on the CAC.

 

[rob the elder]

Well here goes

This is based on my experience and reading over the years.

Adding a CAI does not provide any performance improvement potential. The stock airbox design is very well done and flows plenty of air with little restriction. Adding a CAI should not have an impact on a tune because the stock box flows plenty well enough. This has been demonstrated in many dyno tests over the past 15 years.

The cat is restrictive. Replacing the CAT with a high flow unit has been demonstrated to add between 15 and 18 hp to an otherwise stock car. With the factory tune, the tune is designed to achieve 260 ft pounds of torque and it will incrementally change its baseline settings to achieve that 260 target. This has been called "learn down" but the car will also "learn up" if you set the conditions to call for that. it moves to hit its target and you will not realize any benefits in power from adding a high flow CAT after about 6 key cycles.

Charge tubes are a somewhat controversial subject. In the early days, there were owners who swore that the move to aftermarket, larger tubes that provided smoother flow actually added HP. My experience has been that the stock charge tubes work "ok" and since the motor produces excess power and targets 260 ftlbs, any inefficiency in the factory charge tubes did not adversly affect overall performance. The dyno runs I have seen appear to show the stock charge tubes create turbulence that results in roll off of flow and thus power above 5000 RPM. this results in a curve that begins to flatten after this RPM and constrains the growth of HP near the upper range of the power curve. Replacing the factory charge tubes on the same car will shift the flattening of the curve well up into the higher RPM range. The charge tubes are not "making" more power but their improved flow at higher flow rates is reducing the negative affects of internal turbulence. With a good tune I would certainly keep good charge tubes on the list if you will be driving in the higher RPM range.

There has been a lot of work done testing the intercooler properties. The stock IC is pretty well designed. The consensus I have seen is that for occasional full throttle events, the stock IC is fine. But on a hot day, on the track where the IC is heat soaked, after a few minutes of high demand, its effectiveness is reduced. If you are driving a commuter car and not slamming the throttle for long periods of time, then the heat rejection properties of the stock IC may be fine for you. I replaced my stock IC with a much larger DeJon IC and saw zero change in performance. Had I spent time on the track where heat soak can be an issue, that may not have been the case but you need to make your own assessment. On the other hand, the factory IC has been known to fail with a tune. There were a number of factory ICs that experienced a mechanical failure (the can cracked and opened to atmosphere) that was a result of the increased boost pressure (we were seeing well into the low to mid 20s with the GMPP tune at altitude) was causing a small number of ICs to fail. Again, its a function of how you intend to use the car and your ability to accept risk.

Personally I have had less than optimal experience with custom tunes. I dont want my car tuned within a micron of its ultimate failure mode. A nice canned tune that has performance built in and maintains a nice safety factor is for me.

There are a number of threads discussing dyno performance, how they work, their reliability and accuracy. The take away I left with is that the operator can make the dyno say anything he wants by choosing the settings he applies for altitude and temperature corrections on any given day. He can show you are way down on power or that you are way up on power. Basically the numbers that result are good for comparison on that day but you really cant compare a dyno run in Denver with one done in Orlando.

Enjoy

 

[kgschlosser]

Spot on @rob the elder.

what it all comes down to is what your expectations are and how much you are willing to spend to get there.

 

[JVL]

@rob the elder @kgschlosser @Steveorama @SSolstice Thank you all for the feedback. I will be ordering the high flow cat downpipe, upgraded sensors, and the "canned tune". To start, once those are all done i will see if i am satisfied with how it is or look at anything additional. Thanks again for the comments

 

[JVL]

last question. If i install the high flow cat downpipe and GM stage 1 sensors, will i have any codes/engine problems before i get the tune? At this time they arent doing in person flashes, so i have to send my core in, and then wait to get it back with the tune. Will i be able to drive it safely with the new sensors and downpipe before the tune is added? My father in law has a car lift. so i want to do the work on the lift, then drive it home, approx 1 hour drive, then mail in the ecu core.

 

[JohnWR]

The cat may or may cause a code, but will not cause any running issues. The sensors should not be installed until you have the tune in place.

 

[SSolstice]

last question. If i install the high flow cat downpipe and GM stage 1 sensors, will i have any codes/engine problems before i get the tune? At this time they arent doing in person flashes, so i have to send my core in, and then wait to get it back with the tune. Will i be able to drive it safely with the new sensors and downpipe before the tune is added? My father in law has a car lift. so i want to do the work on the lift, then drive it home, approx 1 hour drive, then mail in the ecu core.

you can’t drive the car without a ecu. You are not going not going to get a check engine light right away with an aftermarket downpipe, but if you install the 3 bar map sensors with a proper map sensor calibration the is not going to be even drivable.

 

[JVL]

you can’t drive the car without a ecu. You are not going not going to get a check engine light right away with an aftermarket downpipe, but if you install the 3 bar map sensors with a proper map sensor calibration the is not going to be even drivable.

Yes , i know i cant drive it without ecu. my plan was to do the bolt on upgrades at my father in laws lift, drive it home. send in the ecu, wait to get the ecu back, install the ecu and 3 bar map sensors. then ill be good to go.

 

[G-Ram]

IMO, about the only difference in adding a CAI is cosmetic. Gets rid of a bunch of bulky plastic and makes the front of the engine look a little bit cleaner.

 

[agent008]

IMO, about the only difference in adding a CAI is cosmetic. Gets rid of a bunch of bulky plastic and makes the front of the engine look a little bit cleaner.

Another advantage is if you live somewhere with low Solstice-specific parts availability. Like I do. I'm going to install a K&N dual flow cone filter just because I can't find a new air filter for purchase in Brazil. Importing ends up costing as much as the K&N which is reusable/washable.

My car is a 2.4 and I have almost all the parts needed to make the swap. Tip: I found a VW MAF sensor housing that is compatible with the MAF sensor on my 2.4. the VW housing has 72mm internal diameter, 80mm outside diameter. The original airbox has the MAF tube with OD of 2.75" (70mm) and I didn't measure ID but it has a rather thin wall. I would say 67 to 68mm ID so only a little bit smaller than the VW tube/housing. VW part # 06J 906 461.