firepinch

My mods: GM Stage 2, R.A.W. intake, CTI header, CTI 3" downpipe, stock catback.
My friend's mod: Injen CAI

I have to say however that I have a leak in my downpipe, I can really feel the air coming out when I put a finger near the leak. But having a leak wouldn't make me loose 10 hp?

From a 40mph roll: We are side by side in 2nd gear, side by side in 3rd gear and I gain a little on him until the end of the 3rd gear. As a result, I get one car on him only when I get into 4th gear.

I thought Im supposed to have at least 20-30 more whp than him, it looks like I have only 10 more whp. I think that my car has something not right at all for sure. Why am I getting this result?

And I did a post about that before, but I didnt have the new downpipe and header during that moment. In that post I said that I could get only 1 car on him when I slam the 4th gear. I said actually 1 to 1.5 but this is really 1 car only.

In both cases, so when I have the CTI header and downpipoe OR not, when I approach the end of 4th gear, he then begins to have a little GAIN on me. So he approach me until he get side by side. So I guess that major heatsoaking for me is the cause, in fact IAT2 get to 150-155F during those times for an IAT1 of 85F...

3 possibilities that I'm thinking:

1- My car health is going down, so Im loosing horsepower
2- The R.A.W. intake doesn't give any gains at all for the GM Stage 2 or worse, it reduces horsepower.
3- Fuel injectors are partially clogued

Now, I may think not right at all and that is a good possibility because I'm not an expert in mechanics. But I have to tell you this:

1- His car is really stock. Stock pulley, stock injector (I can recognize the color), rev limiter at 6500 RPM.
2- He wouldn't spend his money to get his PCM tuned
3- He doesn't know mechanics pretty well (just the basic)
4- He's a well known friend of mine, he's not a liar
3- He's boosting 12.5 PSI

So now, try to explain to me why my car isnt more powerfull than that...

P.S.: I'm sure that someone will "misread" what I wrote, there is a lot of info so please be sure to read again. If you dont understand something that I wrote please let me know. Thanx!

qwikredline

short answer you have a stock exhaust cat back on a 3 inch system a waste of effort you have a 2.25 diameter cork at the end of your system with a very nice quiet but restrictive muffler. and an exhaust leak. FAIL.

Your friends car is running right.

firepinch

OTTP told me that they will fix the downpipe leak. And I'm supposed to get their OTTP 2.5" catback. Do you think that this will solve all of the problem? Like ... should I get 2-3 cars on him after?

But don't forget something, I said that without the new downpipe and header, results were pretty the same. That is all what a GM Stage 2 can do vs stock? Wow!

Stiner

Once you get the 2.5" catback and the exhaust leak fixed you will notice a gain nothing huge though. You really need to pulley down to start seeing the gains from a full exhaust. Qwik knows that a stock catback is restrictive lol.

@nt1ric3-420$$

there r alot of possible factors. Good idea 2 dyno ur car b4 u modify 2 kno how much u gain if any at all. RAW intake, who makes that? CAI r a big factor also, they say some will trigger trouble codes. Injen is 1 of the best they say, Im looking into 1 of those. ANother thing 2 consider is heat soak. That will affect ur performance DRAMATICALY. Ever notice ur car wants to fly with little effort when u first take off in the morning or when the eng is cold? Thats cus after driving 4 a while the heat will "soak" into ur intake manifold in this case, supercharger assembly and affect performance. Heat is the enemy of engine efficiency. Colder air is denser and carries more oxygen which is what u need to ensure better combustion and more power. The faster air travels in and out of the engine the faster the car is. thats y u need 2 adress intake n exhaust mods. Guy there is ryt bout the stock muffler restricting ur flow also heat wrapping ur headers wouldnt hurt. Remember u want 2 keep underhood temperatures down to keep from sucking in hot, power-robbing air.

Tennpenn83

you put a R.A.W. 3" intake on a stage 2 car and didn't tune for it? it's probably making the car run so rich (the stage 2 tune runs rich as **** as it is) that you're losing power

i'd be willing to bet that if you got a retune, you'd pull back those cars pretty easily.

step 1 : get a cat-back and get your header/dp fixed.

step 2 : get a wideband

step 3 : get a re-tune

step 4 : proceed to put busses on your friends car

@nt1ric3-420$$

there r alot of possible factors. Good idea 2 dyno ur car b4 u modify 2 kno how much u gain if any at all. RAW intake, who makes that? CAI r a big factor also, they say some will trigger trouble codes. Injen is 1 of the best they say, Im looking into 1 of those. ANother thing 2 consider is heat soak. That will affect ur performance DRAMATICALY. Ever notice ur car wants to fly with little effort when u first take off in the morning or when the eng is cold? Thats cus after driving 4 a while the heat will "soak" into ur intake manifold in this case, supercharger assembly and affect performance. Heat is the enemy of engine efficiency. Colder air is denser and carries more oxygen which is what u need to ensure better combustion and more power. The faster air travels in and out of the engine the faster the car is. thats y u need 2 adress intake n exhaust mods. Guy there is ryt bout the stock muffler restricting ur flow also heat wrapping ur headers wouldnt hurt. Remember u want 2 keep underhood temperatures down to keep from sucking in hot, power-robbing air.

firepinch

RAW intake... its Rebel Auto Worx who make them! This is actually a 3" intake like the Fujita one, so its supposed to be better than the Injen?? Go figure...

Thanx Tennpenn83 to make me more reassured about my car. You know, when a motor isnt in a good shape, you can loose quite a lot of power depending of how healthy it is... this is what I was affraid of. Its health cannot be that bad because I don't see any symptoms of that, my car seems to run fine but well, I think that my car really should be more powerfull than it is now vs my friend.

For the retune, and etc, I will not have to do this because good news, Im gonna get 3 coolings mods (heat exhanger, dual pass endplate, stu mod), the catback and the OTT Stage 1 with the 2.7" pulley

But you know, I thought that I would be better than that against my friend with the GM Stage2 and my CAI.

So I guess I should expect a HUGE gain once all the new mods will be installed?

@nt1ric3-420$$

holy ****, sorry bout the 2ble post there, site is f in w me as always...

wtpcobaltss

read my sig for my mods..i put lenghts on tc's definetly with ott hook u up..also i paid about 800 dollars for all my mods and ive definetly gained atleast 50whp..and with the price per horespower these days i would def hit up ott...great products..josh actually sat on the phone with me for about an hour while i was in shop trying to figure the **** out..

Stiner

If possible you are always better with a custom tune over a canned one. The OTTP tune is a good tune but there's room for improvement.

Tennpenn83

i'd say it will definitely be a kick in the pants difference. you've got a decent mods list, just make sure ott knows you have a 3" intake or it could **** up the tune again. like i said, the GMS2 tune is hella rich, and you putting mods on top of that would only make it worse without a custom tune.

i agree with stiner. a custom tune is always better, but for the selection of canned tunes, ott is prob the best.

firepinch

Thanx for your inputs guys, this makes me feel better I have to tell you also another reason why I'm worried about my actual performance... As it is right now, my friend is like...

"You got a GM Stage 2 which is supposed to give you a good 30 hp and the upcoming between you and me is only THIS??? GM Stage 2 doesnt worth it at all then, I would even almost not notice it!!!"

Do you see what I mean guys??? The GM stage 2 is supposed to give like 25-30 hp over stock, so that is WHY I can't understand how useless it is in my situation.

So adding an intake and others mods will make you LOOSE hp or what? Its almost impossible. Or in order to gain the hp GM claims which the GM Stage 2, you have to not add any others mods to your car? I would like to explain to him why I don't get as much cars as I should on him!

Also, as a very important side note, don't miss this: If my injectors are maxed out already and I put some mods, I CAN understand that things get worse!!! HOWEVER, and this is the important part, if that is the ONLY cause, I SHOULD PASS HIM when we are in the mid range of RPM's (like 3000 to 5500 RPM) because in those RPMs, the injectors are certainly NOT maxed out already. With the GM Stage 2, I should get like 20 more hp accross all the powerband at least, so when my injectors are not maxed out, I should gain on him. Don't you find????

So there is another reason like maybe less timing or too rich air fuel ratio in the midrange. Don't say heatsoking because I only see a rise in IAT2 when I'm into 3rd gear and this is really in 4th that I really begin to heatsoak, IAT2 right there climb up to 150F. You know, when we start from 40mph, we are side by side until we shift in 3rd, I should just have at least a slight gain on him in second!!! I should make a video of that, its just surprising how much he pulls for a stock car and intake!!

InfraRedline

iTrader: (4)

That seems really odd. When I was stock with intake and cat back only, my friend with gm stage 2 and intake put about 6 cars on me. Same result when I got staged and raced another friends nearly stock ss, I put about 5 cars on him.

firepinch

That is why I thought that I had something maybe wrong with my car...

2K5SS/SC?

My exact thoughts as well. These cars need to flow, be cool running, and properly tuned when modded. Keep all these in check at what ever mod level you are at and the power will be had. If one overpowers the other, then you need to get all the other back onto the same level.

Tennpenn83

i'd be willing to bet that most of the problem has to do with the intake. especially with you having the 3" intake, your maf tables are probably so far off that it made you lose enough power to have a stock car hang with you

put it this way. the redline's K&N typhoon CAI is actually 2.75", while the stock is 3", at least at the maf sensor (i have no idea if this is the same on the cobalts). when you decrease the diameter of the tubing, and you don't change the tune, it ends up flowing more air at higher velocity but the frequency (in Hz) still shows the same airflow as the old tune. so, the computer doesn't think there's that much air flowing so it injects the same amount of fuel. when in actuality, theere is more airflow, and the same amount of fuel, so you'd run leaner, and that's where the power is made. (plus the whole K&Nfilterlessrestrictionetc...)

your car is probably rich as ****, on a GMS2 tune which is already rich as ****. that's where your power loss is. retune, and you'll see a big difference

p.s. my thoughts are still the same, get a wideband first, then get a retune

firepinch

You know what?? It makes A LOT of sense, I think that you made the best physical explanation. I didnt think about that because, you just made me understand how the MAF table works and how the flow is changed in a larger intake tube. I feel really dumb because I justly studied physics at the college and I didn't even think about that!! Those courses werent pure physics, rather "general" physics but still... wow, you are the man! What other people think about that???

But something comes to my mind... Rebel tested their intake on the dyno and they showed a good 10-12hp of GAIN. I wonder if they tested that on a STOCK car or if they changed the tune when they dynoed before and after... I was proud to say that I gained more hp than with an Injen but this is so not the case at all.

And hey, this is certainly why my Interceptor gauge tell me that I have 8 less hp once the R.A.W intake is installed!!! So that gauge doesn't lie!

Other people with the R.A.W. intake and a GM Stage 2 tune or a stock tune, please chime in and tell me what you are experiencing. As it is now, you are supposed to not gain any hp at all!!! I think that I'm gonna do a tread about this to make people pay attention if they buy a 3" intake with a stock tune!

Staged07SS

iTrader: (25)

More air in will lean out the tune .... the raw intake will not make the car more rich on the GM tune. the big 3" intake will lean the tune out a bit.
You dont need to get retuned to run an intake. I have the 2007 GM Stage 1/2 Tune and my car runs very well with the raw intake.

@nt1ric3-420$$

Yeah, thats what ive been thinking d whole time reading all this. Id hate 2 think i hav 2 re-tune just cus I +d an Intake, or exhaust. Even w a free flowing, header/dp/cat. And that extra CFM (should) lean out that mixture...After all, these companies dont say u have to re-tune when u bolt on their products-or are they leaving that **** out?

Tennpenn83

he is not moving enough air at the moment to warrant a 3" intake. that's not saying it won't provide any sort of gain, but if you want to most gain from an intake, then you will get re-tuned for it.

his car is still rich as ****, and needs a re-tune. i'd be willing to bet that if you got a wideband, you'd see that you're running rich too.

do you know how to use hpt?

2K5SS/SC?

Ah so your telling me the ECU can sense a change to its normal operating area and cause the car to dump more fuel over the already rich GM Stage 2 tune? No way!

More air in can infact lean the car out. It gets there by swapping to a smaller pulley to help cram more air in. All a bigger intake will do is mess with the MAF's calibration which in return screws up your a/f ratios and kills power. As TennPenn83 stated, he needs a tune. End of story.

Staged07SS

iTrader: (25)

i know that im running rich i have the GM Stage 2 tune, but im a lot more lean than a car with just Stage 2 due to my Stage 3 pulley and rebel intake leaning the mix out a bit. My car runs great, and im fine with running a little rich, its better than being too lean. i dont have hpt so i dont know how to use it.

BLAZIN07SS

iTrader: (7)

even gm stage 2 w/ a 2.9 pulley pegged the wideband at 10.0 AFR super rich

firepinch

I think that before removing my R.A.W intake, Im gonna install the wideband I just received... Im gonna do this soon so Im gonna know how rich Im running right now and maybe I will see the reason of my bad performance??

Could also the timing be altered with a larger intake or the timing values are fixed in the GM tune?

So if we recap it, the only thing which would be screwed up right now is the MAF reading... This is my actual understanding, am I right?

So if that is the case, I should see it with my wideband because the AF ratio would be changed if the MAF reading is screwed... right?

Im gonna check all of this out soon and Im gonna let you know!