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Discussion Starter · #1 ·
Ok, I finally have enough dough for some lower end headers, side business did well this month. I have about a grand I can spend, give or take a couple hundred. This obviously knocks out the LG's and some of the other players. I am looking at OBX with cats for about 850 or I can get a pair of Texas speed headers for about the same price without cats http://www.texas-speed.com/shop/item.asp?itemid=689&catid=45.

I live in an emission county so I have to be able to hook up to the machine and pass an emission check. I have read about deleting the back o2 sensors. Will this fix the problem of an emission test?

Can I anstall headers and still be ok witout a tune?

If I can get in cheap enough I can probably scrape together a little extra for a BBK aluminum intake with a 80mm throttle body at which point I will have to get a tune. I'm thinking 30 hp just from these two bolt ons. A cam is in the works by Christmas.

Looking for opinions from you guys on which way to go for the most bang for the buck.

Car is a 2000 coupe 6 speed 80k miles CAI and granatelli MAF sensor. Just the way I bought it.
 

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Personally, I would run-not walk- from the BBK manifold. It is heavier than the stock manifold, and is a much much greater heat sink as well-increasing your intake temps and hurting power. you could probably have your stock throttle body ported for what the 80 would cost and have more airflow too.

can't say much about the headers, have no experience with those companies.

Deleting the rear o2 sensors isn't an emissions issue, the rear o2 sensors are just there to see if the cats are working. You can install headers without a tune, you just give up a little hp doing it. Not worth the money imo to tune it just for the headers.
 

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I run the Texas Speed headers with their 3" x pipe/no cats midsection. Their a good bang for the buck option. The coating on mine has help up great and they look almost as good as the day I bought them. Install wasn't too bad either but I believe it's a little more involved than some of the higher end setups. I agree with hardcore, forget the BBK intake. You'll be better off with an LS6 intake or a FAST. I'd dump the Granatelli MAF as well. The rear O2's can be deleted with a tune and you'll need one to see any real gain out of the headers. I can't help you with emissions questions though, none of that here.
 

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Discussion Starter · #4 ·
The grantelli maf came on the car so it has to stay for now unless there is a major reasong for getting rid of it.

so do I just tie the rear o2 sensors up out of the way? Will it pass like that or do I need the tune before the next inspection. I'm good till April next year so no big deal if it throws codes for a while till I can get it tuned.

Can't afford the fast intake but might swing the LS6 intake. I see them on ebay all the time. This would allow me to run my throttle body until I can get it ported?

thanks guys!
 

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You can simply unplug the sensors. If you want to port your throttle body go for it. I did mine and it turned out pretty good, it ain't rocket science. Easiest way is to use a dremel and take your time.
 

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Most giving advice on mods that effect SMOG testing are blowing it out their butts.

1. ANY long tube header is ILLEGAL as to EPA as it moves the CATS and front 02 sensors downstream

2. This causes them to not be hot enough and will not work correctly and cause CATs to degrade sooner

3. You did not say what type of "machine" for smog testing
If they just use a OBD scanner a good tuner can make your car pass with headers and no CATs.

4. Most so called high flow CATS are also illegal and they cake up over time so they are useless and can even increase backpressure over time

5. KEEP the rear 02 sensors they ARE used not just for CATs but also the PCM uses them for the short term fuel trim adjustments. There is ZERO reason to remove them and of course you do that also is EPA illegal.

6. If worried about smog visual testing then only buy parts that have a CARB ID code.

If they do not do a visual then useless to even pay for any CATS, use all 4 O2 sensors and have a real tuner adjust so that all I/M smog tests in the PCM always stay in a PASSED state.

LT headers since they force the front 02 sensors downstream where exhaust is cooler can prevent 02s to not get hot enough or take too long to heat up and fire off.

Use a OBD scanner and after tuning make sure the O2 sensors heaters are working well and that 02 sensors are functioning correctly AND are equal to left/right sides of engine

Use the correct header to manifold gaskets, common wrong ones used causing exhaust leaks which suck in air and fool front 02 sensors.

Put heat socks on sparkplug wires as headers will burn the wires and short them to ground.

Check that headers due to lousy design might be too close to main wiring loom by firewall, if so heat shield the wiring loom

Look at the quality of headers you are buying, some are not even made in the USA and use cheap metal and over time welds will crack and suck air into exhaust.

Use a infrared thermal tool and measure temps at each primary ( around 300 degees), at the front 02 sensors, before and after the CATs and also see that both sides report about the same temps as that will tell you how good or bad the total design was, if engine AFR is too lean or rich and if the CATS are working correctly


Ok, I finally have enough dough for some lower end headers, side business did well this month. I have about a grand I can spend, give or take a couple hundred. This obviously knocks out the LG's and some of the other players. I am looking at OBX with cats for about 850 or I can get a pair of Texas speed headers for about the same price without cats http://www.texas-speed.com/shop/item.asp?itemid=689&catid=45.

I live in an emission county so I have to be able to hook up to the machine and pass an emission check. I have read about deleting the back o2 sensors. Will this fix the problem of an emission test?

Can I anstall headers and still be ok witout a tune?

If I can get in cheap enough I can probably scrape together a little extra for a BBK aluminum intake with a 80mm throttle body at which point I will have to get a tune. I'm thinking 30 hp just from these two bolt ons. A cam is in the works by Christmas.

Looking for opinions from you guys on which way to go for the most bang for the buck.

Car is a 2000 coupe 6 speed 80k miles CAI and granatelli MAF sensor. Just the way I bought it.
 

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Read my other reply.
Do not take rear 02s off, if EPA catches that expect a $10,000 fine. Grantelli MAF is a POS and a gimmick.
All they do is take a stock one and solder a 2 cent resistor in that lies to what the airmass is.
You can cut the resistor out and it again is stock and it is useless because a good tune does not need MAF to be lying

Throwing codes can force the PCM to work in a worse case, pull timing and even drop into low octane timing table long term so you LOSS performance with some codes tripped and each time you clear them you also cut your throat as clearing error codes also causes PCM to put ALL on-board smog tests to a failed state and can take days for those tests to get back into a passed state if at all.

FAST intake and so called porting with stock engine, valves, etc is useless as tits on a bull. 2001 - 2004 intake and TB easy handles NA performance

The grantelli maf came on the car so it has to stay for now unless there is a major reasong for getting rid of it.

so do I just tie the rear o2 sensors up out of the way? Will it pass like that or do I need the tune before the next inspection. I'm good till April next year so no big deal if it throws codes for a while till I can get it tuned.

Can't afford the fast intake but might swing the LS6 intake. I see them on ebay all the time. This would allow me to run my throttle body until I can get it ported?

thanks guys!
 

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You can simply unplug the sensors. If you want to port your throttle body go for it. I did mine and it turned out pretty good, it ain't rocket science. Easiest way is to use a dremel and take your time.
Yea your TB looks great :smack
Interesting you hump the hell out of the outside but the butterfly and internal of TB is still stock so there is zero more airflow and in fact the intake runners and cylinder volume still dictate the flow.
As it is the stock TB and MAF can flow around 800 CFM where stock cylinders only need at most 640 CFM.

Simply unplugging sensor ?

These are Corvettes not ricers and the sensors is why a 450 HP Corvette can get 30 MPG while ricers with far less HP cannot achieve.

If GM could use a $30 for a Dremel and make even 10 flywheel gains they would hire you :WTF

I have seen Corvette that are screwed up to find the bogus "porting" made the metal so thin that over time cracks or holes causing unmetered air leaks screwing up the PCM as to correct airmass.

I suggest you stick with waxing :smack
 

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Yea your TB looks great :smack
Interesting you hump the hell out of the outside but the butterfly and internal of TB is still stock so there is zero more airflow and in fact the intake runners and cylinder volume still dictate the flow.
There is significant amount of material just forward of the butterfly that can be removed. I cut half the shaft and knifed the edge and reduced the size of the PCV hole. Did I pick up much from it, who knows but I do know my throttle response improved.

Simply unplugging sensor ?
I don't know why you think they can't be remove and deleted in the tune. I know very few with long tube headers running rear O2's.

If GM could use a $30 for a Dremel and make even 10 flywheel gains they would hire you :WTF
Why don't you ask those guys who charge a couple hundred to do it.

I have seen Corvette that are screwed up to find the bogus "porting" made the metal so thin that over time cracks or holes causing unmetered air leaks screwing up the PCM as to correct airmass.
I don't care what happens when you work on your car.

I suggest you stick with waxing :smack
 

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I put long tube headers on my 05' with high flow cats, and I could not get a sticker. I had to get a dyno tune to fix that. You may get lucky and pass emissions? Don’t mess with unplugging 02 sensors. If your state uses the sniffer in your tail pipe, then I would leave the factory cats on. If they use the obd plug in under the dash, get the high flow cats, and a tune. The tune will be worth the money with your headers, high flow cats, CAI, and MAF. If you are looking for a throttle body, don't mess with yours. Check this guy out http://http://www.mikenorrismotorsports.com I have one of his on my 05'. He uses machine porting on his throttle bodies, and to my knowledge is the only one that does this. That is way better than a dremel and free hand. If the dremel action is off a little it will cause more air turbulence, than factory. Good luck.
 

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Total cyberspace punk

You cannot change one part of a air path and cause the cylinder volume to increase and you do not drive in outer space
The only thing polishing your TB does is a change of sound which is assumed performance gains when your engine is never even near the max airflow.

Again put a OBD scanner on and you'd be lucky to be using 40 pound/hr of air at WOT when air and fuel total with stock 346 CI is less then 1.2 grms to fill cylinder !

You can bet the max air used is only about 600 CFM which is no where near the maximum of the stock TB flow of 750 CFM.

I really do not care what vendors chump Corvette owners for AIR mods as you cannot overcome the laws of physics or volume capacity

Kinda stupid when only ONE piston at a time needs less then 1.2 grms when the intake manifold alone is a reserve and has plenty of spare volume.

Unless the WHOLE TB air path was increased which also means a larger butterfly then screwing with a dremel on the front side is useless and even then the runner of intake and intake valve size would prevent higher flow but again the cylinder volume of 1 cylinder is far less then reserve of intake.

Being the TB is controlled by PCM and TCM as drive by wire reaction/response time can simply be tuned in.

As to yanking out the rear 02 sensors, ask those vendors and the main supplier of rear 02 simms who got wacked by EPA with a $100,000 fine why they do it and the answers are they are dumb F*ucks and con artists as their header design is piss poor causing the front 02 sensors to be 12 to 18 inches downstream and now 02 wires are too short so they con the customers to steal the rears and use them in the front

PCM uses the REARS in each drive cycle to determine what the average fuel injector pulse width will be, to use to adjust the short term fuel trims, for testing of smog functions like AIR and for testing CATs.

EPA is wise now as to rear 02s and if caught owner is wacked $10,000.
Using CATS that have no CARB ID is also illegal.
Moving CATs and 02 sensors is also illegal and any air part that effects engines AFR/exhaust makeup screwed with is also illegal

I do not care what you do with your car but do not tell others to simply hack crap when their ass can get wacked by state and EPA.

As to proof the same TB used across the C6 engines, so if a ZR1 can support 650 HP the same TB can handle 450 for a LS2 much less the same 85 mm TB on a LS6 such as mime handle 700 flywheel HP.


There is significant amount of material just forward of the butterfly that can be removed. I cut half the shaft and knifed the edge and reduced the size of the PCV hole. Did I pick up much from it, who knows but I do know my throttle response improved.



I don't know why you think they can't be remove and deleted in the tune. I know very few with long tube headers running rear O2's.



Why don't you ask those guys who charge a couple hundred to do it.



I don't care what happens when you work on your car.
 

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I do not care what you do with your car but do not tell others to simply hack crap when their ass can get wacked by state and EPA.
Do you even live in TX? He's a big boy and knows the rules in his own state. He asked a question in regards to running off road headers. Since it's clear you don't know anything about the headers he inquired about maybe you should just STFU.

As to proof the same TB used across the C6 engines, so if a ZR1 can support 650 HP the same TB can handle 450 for a LS2 much less the same 85 mm TB on a LS6 such as mime handle 700 flywheel HP.
You're comparing an FI car to NA? :laughing:
 

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Do you even live in TX? He's a big boy and knows the rules in his own state. He asked a question in regards to running off road headers. Since it's clear you don't know anything about the headers he inquired about maybe you should just STFU.



You're comparing an FI car to NA? :laughing:
Hey numb nuts,

ALL LONG tube headers are illegal, if in Tx or Ca, it is a FEDERAL law not a state only law.

What OP is asking and what the dremel dude is saying are getting different responses from me.

A forum is not speaking to a HE, it is all those reading and those wanting answers OP asked as to what passes state and federal laws and what happens long term when people say rip the o2 sensors out and F*ck yourself when state or feds wack a owner because he only hears one side of the mod story.

Makes no difference what the brand are, IF they do NOT have a CARB ID and the buyer knows it then they also need to know what CAN happen in smog test shops or a COP doing a visual

The OP says he is in a emissions county and he is light on money so you can bet he is not going to spend 2 plus hours each time he wants OFF road headers on for track only use and if you believe people do that then you need to polish your pecker with that guy's dremel :nuts:
 

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I have run long tube headers with all sensors active for 5 years. I have passed emissions with an annual tune. I have thrown rear sensor codes in winter cross-winds but it is rare and I reset the codes with a scan tool.

If you disconnect the sensors they will show XX on the emissions test report. A good tune is a better option than removing the sensors IMO.

:cheers:
 

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Discussion Starter · #15 ·
some simple questions and it gets ugly in here:WTF

I pulled the trigger on a set of obx with cats on ebay. 495 plus 99 for shipping, for less than 600 Ill have everything emission ready. I know I will need a tune down the road but am ok until April on the sticker. No sniffer here so just a ODB plug in. Will I need new header bolts or can I reuse the stock manifold bolts?

Hopefully I can get these on before we leave for vacation.
School is out in a few weeks and I will have about 4 days before we leave for the coast. Won't be back until August. 9 glorious weeks of wind and waves.
 

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Discussion Starter · #16 ·
Midnite where do you get your car tuned? I am in Arlington so not far from you. I have been looking a Thompson motorsports
 

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I would put a nice set of stainless steel grade 8 bolts on. Use some lock washers and high strength lock tight. The problem you might run into with aftermarket cats, as I did also. They can’t burn off the gas like the factory ones. This might not happen with you? I put on a set of random technologies cats on, that were supposed to be emission legal. Within 2 days the car's rear o2sensors picked it up, threw codes on the dash and started to retard timing and give less fuel. The car didn't have the gitty up and go, that’s why I had to have it dyno tuned. I would send midnite902 a pm to find out about his tuner. That way he will get it for sure. Good luck with the added power.:partyon:
 

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Midnite where do you get your car tuned? I am in Arlington so not far from you. I have been looking a Thompson motorsports
All my work has been performed by 21st Century Musclecars in Addison. 21CMC is a Lingenfelter and Callaway performance shop. 21CMC is also authorized to perform GM warranty work under GMPP.

:cheers:
 

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Will I need new header bolts or can I reuse the stock manifold bolts?
You can reuse them. Use some antiseize on them and torque to spec. You may want to get a new set of gaskets though if your kit doesn't come with them.
 

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You can reuse them. Use some antiseize on them and torque to spec. You may want to get a new set of gaskets though if your kit doesn't come with them.
Do not use the OBX gaskets, buy new GM ones.
 
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