Reason for switching to a carb intake??
Back on the subject, i have been kicking around this idea for the past few days, i am going to try and run as many channels(egt and wideband) as i can and maybe i can convince someone 
to do some extra pulls and tune with a stock style intake......maybe.
to do some extra pulls and tune with a stock style intake......maybe. Last edited by kp; Nov 10, 2006 at 07:36 PM.
Back to the original poster's question. Let's see some dyno charts or individual cylinder EGT data or burst pressure data to prove or disprove any benefit to a carb style intake over the gm plastic.
cross quoting from another thread so these wont show up in the ls1tech email reminder of the thread, you are just going to have to visit this thread live to read this.
thank you for your input Jose
and here are some if not most of the information kp shared , thank you as well
since half of the runners are different sized The flow is "controlled" by the length and width of the runner, So in a perfect world the flow is the same, correct?
What intake is ?
i have thought about that before but until you wrote it down i guess i never really wrapped my head around it. I sure wish someone( not me) like one of the heavy hitting sponsors would do some back to back fi dyno pulls using some of the different intakes including a sheetmetal intake
as far as Egts and wideband, 8 egts and 1 wideband, sound off?
i figure with 8 egts you could see if one cyl is off and correct it ..??..
One of the other questions i have is the use of sheetmetal intakes. i choose to use a carb style intake and have just about as much invested in it as i would have with a sheetmetal, does anyone have any hard data or are most of us playing the guessing game....
kp stated something i also found very interesting it is about the #7 cyl which was one of the reason i also went with a carb style intake... can anyone else debate this?
*most of this was posted in another thread a day or so ago*
Originally Posted by JZ 97 SS 1500
Ok, first on a bread box style intake (like an LT1) the rear cylinders typically will be leaner under boost and the first 2 leaner under vacuum. Since the air is being pressurized inside the intake it does tend to equalize somewhat but typically you will see #7 and #8 being the hotest 2 cylinders under boost. As you move to a carb style intake the conditions lessen by a substantial margin since now the air is being introduced from above and not from a perpendicular angle to the cylinders. Also with BS3 you do have individual cylinder control, so you can effectively control the A/F in each hole.
Jose
Jose
and here are some if not most of the information kp shared , thank you as well
Originally Posted by kp
Where this 'great' distribution comes from is beyond me, the inner four runners are shorter then the outer four. They compensate for the length by changing the size and shape of the port entrance and the cross section of the runner itself and tweaking the plenum. Thats all fine and dandy except the GMPP and victor JR were designed to be used with carbs and not necessarily high boost, elbowed/single TB combos.
If you are trying to extract the last bit of horsepower you need to monitor each cylinder and have a means to adjust it, throwing a carb style intake on isnt going to give you better distribution out of the box IMO. I can tell you first hand they they sure dont on a N/A LS1 engine. But for most people who are going to run their combo in the 'safe' zone either intake isnt going to give you perfect distribution.
So far there is not one direct dyno comparison between a single plane intake and stock type on a forced induction LS1, let alone 8 EGTs or 8 wideband comparisons so unless the data is there its just speculation to me. I'm not saying that the current single plane intakes dont offer some flow advantage on high boost/hp setups but there a lot of boosted cars out there making some serious power with LS6 and LS2 intakes..
If you are trying to extract the last bit of horsepower you need to monitor each cylinder and have a means to adjust it, throwing a carb style intake on isnt going to give you better distribution out of the box IMO. I can tell you first hand they they sure dont on a N/A LS1 engine. But for most people who are going to run their combo in the 'safe' zone either intake isnt going to give you perfect distribution.
So far there is not one direct dyno comparison between a single plane intake and stock type on a forced induction LS1, let alone 8 EGTs or 8 wideband comparisons so unless the data is there its just speculation to me. I'm not saying that the current single plane intakes dont offer some flow advantage on high boost/hp setups but there a lot of boosted cars out there making some serious power with LS6 and LS2 intakes..
Originally Posted by kp
They compensate for the length by changing the size and shape of the port entrance and the cross section of the runner itself and tweaking the plenum... ..
since half of the runners are different sized The flow is "controlled" by the length and width of the runner, So in a perfect world the flow is the same, correct?
Originally Posted by kp
Thats how its supposed to work but remember carb intakes are made not only to flow air but keep air and fuel mixed together as well as they can and the plenum comes into play there also. What works perfect at one bar with a carb may change at 2 bar or 3 bar with port injection....
Originally Posted by kp
GMPP and victor JR were designed to be used with carbs and not necessarily high boost, elbowed/single TB combos... ..
Originally Posted by kp
off the shelf? none as far as I know. But the stock type intakes arent too bad The #7 thing open to debate, people have turned the stock intake manifold around and number 7 still ran leaner why is that? I'll let the guys with engine dynos figure that out, for me I'll just toss a couple more % of fuel in that cykinder. Why dont the LSX intakes help the #7 problem either.....
Originally Posted by kp
So far there is not one direct dyno comparison between a single plane intake and stock type on a forced induction LS1, let alone 8 EGTs or 8 wideband comparisons so unless the data is there its just speculation to me. I'm not saying that the current single plane intakes dont offer some flow advantage on high boost/hp setups but there a lot of boosted cars out there making some serious power with LS6 and LS2 intakes.. ..
as far as Egts and wideband, 8 egts and 1 wideband, sound off?
i figure with 8 egts you could see if one cyl is off and correct it ..??..
Originally Posted by kp
Eight widebands or eight EGTs, or if you have the time you could simply pull the plugs after dyno pulls and see what happening. ....
Originally Posted by kp
Only safe guess is to use what other people are running well with and be happy unless you have the means to test and develop something better I'm not saying the carb intakes are any better or worse then the stock style, honestly I have no idea, but I can say the single plane GMPP on the NA 414 I had picked up nearly 80rwhp by evening out the cylinders using a four channel EGT.
*most of this was posted in another thread a day or so ago*
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since half of the runners are different sized The flow is "controlled" by the length and width of the runner, So in a perfect world the flow is the same, correct?
in the real world, this only works perfectly if the engine is only run at one constant speed. but in a car, where the intake has to operate from idle to redline, with constantly changing vacuum or boost pressures, theres still a difference in airflow between the cylinders
lets change the situation a bit, lets say were talking about moving air through air ducts in an office HVAC ...the only way to pump the exact same amount of air through 2 different sized vent shafts under all conditions (hi speed, low speed) is to have 2 different fans on seperate contols
run both systems off the same fan (cough same size cylinder on an engine) and youll have different air flows at different speed
This is why ITB's are used in alot of the "money is no object" road racing classes ... because all the ports are the same length / shape behind the butterfly plate, and the plenum has much less effect on airflow (if any)
Originally Posted by HotRodKid
lets change the situation a bit, lets say were talking about moving air through air ducts in an office HVAC ...the only way to pump the exact same amount of air through 2 different sized vent shafts under all conditions (hi speed, low speed) is to have 2 different fans on seperate contols
run both systems off the same fan (cough same size cylinder on an engine) and youll have different air flows at different speed
run both systems off the same fan (cough same size cylinder on an engine) and youll have different air flows at different speed
in my mind here is what i think is happening , with a stock style intake the intake charge has to hit the back of the intake before its pressurizes to even out the air flow , thus forcing more air into the rear cyls until it does, while only for a very very short time, with FI thats alot more air then a N/A. With the carb style intake the charge hits the bottom plenum which has a "more" even spacing between runners. now even though the runners are different sizes flow should be controlled by length and width. i understand your statement about idle to WOT changes but wouldnt that make an even more differance between the two types of intake?
Originally Posted by HotRodKid
This is why ITB's are used in alot of the "money is no object" road racing classes ... because all the ports are the same length / shape behind the butterfly plate, and the plenum has much less effect on airflow (if any)
Individial throttle body.
I doubt the boost hits the back wall and causes more air to get to the rear cylinders with 6 other cylinders before it leaking some of that air. IMO the #7 thing happens the most on NA cars with a wet shot at the TB. How many 700hp+ well built FI engines have killed the #7 cylinder? I check my plugs pretty often and number one always seems the leanest for some reason and the leakdown is pretty even across all cylinders so I dont know..
I doubt the boost hits the back wall and causes more air to get to the rear cylinders with 6 other cylinders before it leaking some of that air. IMO the #7 thing happens the most on NA cars with a wet shot at the TB. How many 700hp+ well built FI engines have killed the #7 cylinder? I check my plugs pretty often and number one always seems the leanest for some reason and the leakdown is pretty even across all cylinders so I dont know..
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Verdad Gallardo kp how lean have you seen the #7 and what is your opinion as to why as you mentioned reversing the intake had no effect on #7.
About my statement , is it off base? does it not at least sound right?
About my statement , is it off base? does it not at least sound right?
I would really like to see some bench tests on this. Reading the GMHTP latest issue, the article "Ohio Boys 8 Second turbocharged CETA", it mentions that the original block it had (Stock bottom end) Single 91.5mm turbo, and with new heads that were flowing better than previous (366cfm at .650-inch lift on the intake side), they noted that the LS6 intake and ported stock throttle body were deemed "insufficient. They threw on a Vic Jr and the Elbow, and noticed a drop off in boost at high rpm due to better flow. Obviously the car was already pushing im sure close to 1000rwhp or more as it was already running mid 8's before the switch. But they did notice better "flow" with the "Carb Style" intake? I guess I like to be proven with numbers.
Originally Posted by KHShapiro
kp how lean have you seen the #7 and what is your opinion as to why as you mentioned reversing the intake had no effect on #7.
About my statement , is it off base? does it not at least sound right?
About my statement , is it off base? does it not at least sound right?
As far as turning the intake around I was talking with one of the shops here that do a lot of OE GM stuff and thats where I heard about turning the intake around not making much difference.
I dont know if you are wrong or not, but I do think forced induction isnt as critical as n/a as far as intake distribution goes. If I had an engine dyno and a few hundred hours to spare maybe I could tell you for sure but like most I just rely on experience, real data and a little common sense to draw a conclusion. Dwelling over it and trying to find an answer no one has can make you crazy and no one is going to spend the time or money doing a direct comparison unless they have something to sell and get some return off of the R&D time.
Originally Posted by stevieturbo
.
Ive said it before though. I'm not convinced I have gained any huge amounts of power by fitting one though.
it feels stronger in the low-mid range, and did require a fair bit more fuel in these areas.
But up top....I had to do very little to maintain the same AFR's as per LS6/Stock TB intake.
Dont have access to a dyno, so cant give any numerical evidence for power etc.
Ive said it before though. I'm not convinced I have gained any huge amounts of power by fitting one though.
it feels stronger in the low-mid range, and did require a fair bit more fuel in these areas.
But up top....I had to do very little to maintain the same AFR's as per LS6/Stock TB intake.
Dont have access to a dyno, so cant give any numerical evidence for power etc.
this is what i got from Stevies post
to me it seems he didnt have to do much up top because the charge was already stable up top therefore not much needed to be changed
it was the low to mid that he did the most tweaking on when the charge was unstable.
what was the data low to mid before and after?
am i looking into to this too much?
there is just something that is just bothering me but i cant put my finger on it.
my spider sense is tingling
.... there has to be something more to this 
Originally Posted by MyWs62FaST4u
are there pics or specs on these intakes, or is the vic jr just the way to go? i want to run one on my FI 408, but i might just use the LS7 if anything...
The GMPP is better as far as clearance goes, but needs work done to get the rails to fit. The new Vic Jr's are ready to go to fit the rails, but sit higher and you may have clearance issues.
Originally Posted by LS2Camaro
I would really like to see some bench tests on this. Reading the GMHTP latest issue, the article "Ohio Boys 8 Second turbocharged CETA", it mentions that the original block it had (Stock bottom end) Single 91.5mm turbo, and with new heads that were flowing better than previous (366cfm at .650-inch lift on the intake side), they noted that the LS6 intake and ported stock throttle body were deemed "insufficient. They threw on a Vic Jr and the Elbow, and noticed a drop off in boost at high rpm due to better flow. Obviously the car was already pushing im sure close to 1000rwhp or more as it was already running mid 8's before the switch. But they did notice better "flow" with the "Carb Style" intake? I guess I like to be proven with numbers.
kp you are right. for some reason this is driving me crazy. truth be told i could not sleep lastnight going over this in my head. if things go right i should be able to hit the dyno mid december, if the bank account allows i am gonna try to find out... 
i'll lay this to rest unless someone has something new to add either for or against
i'll lay this to rest unless someone has something new to add either for or against
9 Second Club
Joined: Nov 2003
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From: Norn Iron
Originally Posted by Pro Stock John
I like Stevieturbo's comments, I think his retuning shows how the carb intake impacted his old tune. Stevie, did you go faster?
Yes I did run faster. But my 10.54 @ 145mph/stock LS6 intake was run on 245/50 Nitto's, and the 10.04 @ 148mph Victor Jnr 85mm TB was on 255/50 MT DR's
So a lot of the faster time, is contributable to the tyres ( and it was a cooler day, although I think the meth would take care of that difference on warm days, as intake temps werent much different )
Traps may be telling a different story though ( although tyres are also affecting gearing, which is limiting my trap speed also, as I am well beyond peak power, but hanging onto 4th.
The Nitto run in July picked up around 33mph in the latter 1/8th. I had 3 passes, traps were 143/144/145mph.
The MT DR runs in October picked up around 36-37mph on average, trapping at 147/148/149 average.
That could be down to extra power.....it could also be down to better gearing due to the slightly taller tyres, as I was still crossing the line circa 7000rpm.
Last edited by stevieturbo; Nov 11, 2006 at 11:22 AM.
Originally Posted by KHShapiro
kp you are right. for some reason this is driving me crazy. truth be told i could not sleep lastnight going over this in my head. if things go right i should be able to hit the dyno mid december, if the bank account allows i am gonna try to find out...
i'll lay this to rest unless someone has something new to add either for or against
i'll lay this to rest unless someone has something new to add either for or against
Stevieturbo has done a before and after but different weather has a big effect on a blower car. Even though the meth wil lower the IAT in the summer it wont make up for the extra boost you will see in cooler weather. I am glad he looks at things in a more analytical manner and not the 'I ran 3mph more and it MUST be the intake' like a lot will say. Maybe it is the intake that picked him up 3mph
If someone could prove to me that near my HP level I could pick up even 20hp average doing the intake swap I would be all over it. 
kp, here's some stats that have bothered me for a while.
LPE 345ci TT gains nothing (per LPE) with a FAST 90 over a LS6 at 16-18 psi.
LPE 427 TT gains 30-40rwhp (per LPE) with a FAST 90 over a LS6 at 16-18 psi with the same GT2871R turbos.
Comments?
LPE 345ci TT gains nothing (per LPE) with a FAST 90 over a LS6 at 16-18 psi.
LPE 427 TT gains 30-40rwhp (per LPE) with a FAST 90 over a LS6 at 16-18 psi with the same GT2871R turbos.
Comments?
Originally Posted by onfire
kp, here's some stats that have bothered me for a while.
LPE 345ci TT gains nothing (per LPE) with a FAST 90 over a LS6 at 16-18 psi.
LPE 427 TT gains 30-40rwhp (per LPE) with a FAST 90 over a LS6 at 16-18 psi with the same GT2871R turbos.
Comments?
LPE 345ci TT gains nothing (per LPE) with a FAST 90 over a LS6 at 16-18 psi.
LPE 427 TT gains 30-40rwhp (per LPE) with a FAST 90 over a LS6 at 16-18 psi with the same GT2871R turbos.
Comments?
You are looking at a big engine with tiny turbos so who knows whats going on there.