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Head pipe clearance is a huge issue on factory exhaust set ups in mid 60’s GTO’s. I have seen and fixed too many head pipes that are crushed flat and bent.
The Vektor design could never result in a problem but given how low the car is I don’t think it makes sense.
ClassJ: You are entitled to your opinion and I happen to agree with you on this. It makes no sense to take even a 1% risk in serious damage for unknown gains especially with other "no risk" options.
Basic666: Now I need to correct you . I never ever asked Vektor for any discount, I only asked if they would be willing to give me a full refund if my dyno results weren't reasonably CLOSE to theirs.
Vektor refused to offer any refund on the part for any reason, Fabspeed and Kline did. The Fabspeed and Kline will be tested and everything is in the works.
And since all of you are so interested.. I made my decision last night to go with the Klines. I will independently dyno them and post all of the figures. They are a proven German company that has been doing this for ever and work closely with Porsche. Vektor is a new company with limited history and NO previous work with Porsches, only Subaru's, so that also factored into my equation.
spdracerut: I am going to take measurements as you suggested as I am not "agreeing" with Basic666's current "fingernail" measurement as I dont have an 11mm fingernail, but I will get pics and measurements shortly..
Ok so here are the real numbers as measured by me. Not from other members or from internet websites or anyone's PM's.
Stock Crossmember sits 4 11/16th inches from the ground. Almost 4 3/4 inches
The Stock Headers sit 5 5/8th from the ground or about 1 1/16- 1 1/8 inch HIGHER than the cross member
If the Vektor Headers sit 11mm lower than the crossmember (converted to approximately 7/16"), then the Vektors sit exactly 1 1/2-1 9/16 inches lower than the stock Headers do
There it is in a nutshell. To make numbers nice and round:
Stock Headers sit 1 1/8 ABOVE the crossmember
Vektor Headers sit 1/2 inch BELOW the crossmember
The final answer really comes down to whether or not the design of the Vektors improves performance in any way over stock or other designs.
If the answer is YES, then you have a decision to make based on performance vs. reduced ground clearance.
If the answer is NO, then you just bought a part that doesnt improve performance over other headers, costs significantly more, reduces ground clearance and puts your engine at risk if you catch the header on something lower than the crossmember.
I will do my part with the Kline testing. The Fabspeed is already being tested and if someone wants to put forth some independent Vektor dyno charts then we will have the answers we seek..
ClassJ: You are entitled to your opinion and I happen to agree with you on this. It makes no sense to take even a 1% risk in serious damage for unknown gains especially with other "no risk" options.
Basic666: Now I need to correct you . I never ever asked Vektor for any discount, I only asked if they would be willing to give me a full refund if my dyno results weren't reasonably CLOSE to theirs.
Vektor refused to offer any refund on the part for any reason, Fabspeed and Kline did. The Fabspeed and Kline will be tested and everything is in the works.
And since all of you are so interested.. I made my decision last night to go with the Klines. I will independently dyno them and post all of the figures. They are a proven German company that has been doing this for ever and work closely with Porsche. Vektor is a new company with limited history and NO previous work with Porsches, only Subaru's, so that also factored into my equation.
spdracerut: I am going to take measurements as you suggested as I am not "agreeing" with Basic666's current "fingernail" measurement as I dont have an 11mm fingernail, but I will get pics and measurements shortly..
Ok let me know how that goes! I hope they really return your used headers if they don't work out. Good for them. And if you are throwing them on yourself, let me know if you get stuck with anything. I agree that kline had a history of working porsches. But I don't know why they wouldn't bother with dynoing their own products if they believe it improves performance.
Now on the last part, I don't know why i keep entertaining this, because i literally have nothing to gain from all this, so i don't know why i would be making stuff up. For all i care vektor could close up shops tomorrow and it would have zero impact on my car and my life. But just to show you...
Compare this with the pics above, the finger nail is exactly the width of the difference. The long line under the metal piece, and the long line next to the number 2. In fact my finger nails are a little wider than the diff, and only the tip fits in this range. Edit - actually looking at them again, it starts at the line after the metal piece, and ends at the big number 2 line. So not the tip but the whole finger nail, here's a better pic
Now on a ruler in CMs. The finger nail measures about to be 1cm which is 10mms. This is my index finger BTW. I'm asian and have rather skinny fingers. Curious what yours measure to since you "don't have 11mm finger nails" lol. Gotta love rennlist and where the discussions take us
Oh and since you pretty much lost 10 grand of virtual money, mind converting that to 150 real life money and sending it to me so i can go do some dyno on the vektor headers?
And since all of you are so interested.. I made my decision last night to go with the Klines. I will independently dyno them and post all of the figures. They are a proven German company that has been doing this for ever and work closely with Porsche. Vektor is a new company with limited history and NO previous work with Porsches, only Subaru's, so that also factored into my equation.
Found a decent picture of the Kline headers. They look to sit a little below the oil pan, about even with the cross member. Not as low as the Vektor on the driver's side of course. Just a heads-up.
@PTS-BRG i get where you are coming from, and i believe you have good intentions. but when you act so extreme its hard to take you seriously. and when you are acting like this is your life's crusade or something, people either think you are crazy, or you have personal biases (like maybe its because the folks at vektor did not offer you a discount lol). I think you made your point the first time (and quite a few times after that). Like you said the information is all here, its up to the individual to make the decision. And screaming at people over and over again rarely change their mind. But like i mentioned earlier, something a lot more constructive would be to get yourself a set of kline headers like you promised, and let us know how they perform with just headers alone. You did state at one point they offered to refund if they don't measure up to promised performance.
The folks at vektor are pretty cool peeps. Being my first car install, i ping'd them quite a bit throughout the process, and the dude stayed up way late into the night to help me through it. Do i think they tried to cheat all of us by purposely giving out false info? I really doubt it. I think with the way you were arguing on the forums, everyone would've called u bs. in fact most people did, even i called you bs.
My ruler is 3". I attached the ruler difference below, from lowest part of the beam and lowest part of the headers. Give or take 10mm when converted. To put that in perspective my finger nail fits right in the diff on the ruler. So if you are worried about your car having a finger nail's width of less clearance, stay away!
@Psorcery finally a more constructive comment! I've been reaching out to shops in the bay.. So far only one of them seem to have adequate equipment and have gotten back to me. They are charging $150 for 3 pulls.
With regards to the dyno set up, just make sure they don’t set it up like in the picture for your car. It seems it is correct for a Turbo, but not for the 3.0 turbo. Read this: http://www.litchfieldmotors.com/blog...-tuning-begins
And then the second part of the story which describes yet another header. I don’t think this has been mentioned here before?
With regards to the dyno set up, just make sure they don’t set it up like in the picture for your car. It seems it is correct for a Turbo, but not for the 3.0 turbo. Read this: http://www.litchfieldmotors.com/blog...-tuning-begins
And then the second part of the story which describes yet another header. I don’t think this has been mentioned here before?
Wow, thats the first time i've seen fans being setup like that! Thanks for the info. Regarding the headers, i do wonder at this point, does length matter? (yep we are going there)
Given that a few headers out there now are all equal length, why some felt the need to be longer, and ended up eating into some clearance of the car? I read in another post someone mention for the most performance gain, you want to be in the goldie lock zone of length, not too long not too short (just like, you know...). I do wonder how these manufactures figure this stuff out, as i would imagine it gets pretty expensive to test out different length prototypes. Any insights @VektorPerformance ?
With regards to the dyno set up, just make sure they don’t set it up like in the picture for your car. It seems it is correct for a Turbo, but not for the 3.0 turbo. Read this: http://www.litchfieldmotors.com/blog...-tuning-begins
And then the second part of the story which describes yet another header. I don’t think this has been mentioned here before?
I saw that article about the airflow during dyno testing by Litchfield a while ago. It shows how much variability there is in dyno testing and why it can be difficult to do any direct comparisons. I've come to accept the blower fans blowing into the IC duct outlets as the standard operating procedure for the 991.2 Carrera. It might actually work better than trying to blow into the inlets at the base of the spoiler as the ICs are right there. A potential downside I thought of is the warmer air exiting by where the engine sucks in air thereby skewing the data a little. But one blower placed at the IC duct outlet is easy for every dyno shop to do and it's certainly better than no attempt at flow to the ICs.
Their header is basically the same as Fabspeed in concept.
Question: is Fabspeed equal length as Litchfield? I’m not sure I understand what you’re saying regarding placement of the fans? The Carrera doesn’t have the intake where the turbo does and hence they changed the placing, is what they’re saying, isn’t it? If so, do you think it still is correct to place the fans where the air is trying to exit, just because every one else has done it? Or have I misunderstood everything and also are you saying Litchfield are wrong in their statement regarding turbo vs Carrera with turbo? Just trying to understand what is being said here and who are doing it the wrong way.
Question: is Fabspeed equal length as Litchfield? I’m not sure I understand what you’re saying regarding placement of the fans? The Carrera doesn’t have the intake where the turbo does and hence they changed the placing, is what they’re saying, isn’t it? If so, do you think it still is correct to place the fans where the air is trying to exit, just because every one else has done it? Or have I misunderstood everything and also are you saying Litchfield are wrong in their statement regarding turbo vs Carrera with turbo? Just trying to understand what is being said here and who are doing it the wrong way.
Question: is Fabspeed equal length as Litchfield? I’m not sure I understand what you’re saying regarding placement of the fans? The Carrera doesn’t have the intake where the turbo does and hence they changed the placing, is what they’re saying, isn’t it? If so, do you think it still is correct to place the fans where the air is trying to exit, just because every one else has done it? Or have I misunderstood everything and also are you saying Litchfield are wrong in their statement regarding turbo vs Carrera with turbo? Just trying to understand what is being said here and who are doing it the wrong way.
Neither Fabspeed or Litchfield are equal length. I just read the Litchfield article again and they are wrong. More equal than stock, but not equal length. Kline and Vektor are. As for airflow direction through the intercoolers, below are some pics. Both the 911 Turbo and 991.2 Carrera have the IC placement in the same basic location behind the rear tire. They are angled differently due to where they get their cooling air from. The Turbo has massive scoops in the rear fenders that feed air to the ICs and the air dumps out the duct behind the rear tire. The Carrera gets its IC cooling air from behind the rear glass, same location as the engine/turbo compressor intake air. With the cars on the dyno, it's not easy to place a high flow blower at the intake on either the Turbo or 991.2 Carrera, so people just blow air to the IC through the outlet duct behind the rear tire. The downside with the 991.2 Carrera is now warm air is coming out in about the same location as the air getting sucked into the turbos, so there can be some contamination. But it seems to be a minor effect.
Wow, thats the first time i've seen fans being setup like that! Thanks for the info. Regarding the headers, i do wonder at this point, does length matter? (yep we are going there)
Given that a few headers out there now are all equal length, why some felt the need to be longer, and ended up eating into some clearance of the car? I read in another post someone mention for the most performance gain, you want to be in the goldie lock zone of length, not too long not too short (just like, you know...). I do wonder how these manufactures figure this stuff out, as i would imagine it gets pretty expensive to test out different length prototypes. Any insights @VektorPerformance ?
I snagged some pics of an article on exhaust header design. April 2009 issue of Racecar Engineering.
These two pics talk about the merge design.
This one talks about primary length design as related to turbo cars. Interesting it on the 'tight bends'.
So, with this information, it helps for analysis between Fabspeed/Litchfield, Kline, and Vektor.
Vektor refused to offer any refund on the part for any reason, Fabspeed and Kline did. The Fabspeed and Kline will be tested and everything is in the works.
We offer a lifetime warranty that is similar to others in this market. Same with the return policy. So you got Kline and Fabsped to agree to document a comparison, testing, and reviews from you and will allow for a full refund for the loosing product?
Kline: Under no circumstances can an order be returned. However should an order have a defect, we will cover this under our warranty policy .
Fabspeed: To qualify for return, the product must be unused and remain in undamaged and sealed original packaging, as well as match the current design and packaging for the product at the time of return, unless otherwise stated with product or within the warranty page of Fabspeed Motorsport Site.
Originally Posted by PTS-BRG
I made my decision last night to go with the Klines.
What happened to testing all the headers (including ours, even though we were not giving you a "I will test you product discount")? You had said you were going to test them all and show us all who made the best header. Is that not happening?
I do wonder how these manufactures figure this stuff out, as i would imagine it gets pretty expensive to test out different length prototypes. Any insights @VektorPerformance ?
It's just VERY expensive! The hardware and software required to run true engine exhaust simulations is extremely expensive. Even with the upfront engineering, design, and software simulations, there is still testing to verify and validate the design. Having been through this process many times over the years you learn best practices, which help the development process. The article posted by spdracerut is a good primer. There are lots of books out there on the subject as well, specific to turbocharged manifold design.
As far as equal length goes, it depends on the engine; specifically the exhaust ports. Some engines have exhaust ports that are not the same from port-to-port; One port may have a dog-leg, longer, shorter, or shaped differently than the port next to it. It's not nearly as common, but this would be an instance where an unequal length manifold would make sense.
With the 991.2 engine, the ports are all identical. This means you are going to get the most benefit by optimizing with equal length primaries. To further complicated matters the amount of bends and total angles also plays into 'equalness'. In other words, a 20" straight tube does not equal a 20" tube that has a 180* bend. Even though they are the same length, the shape will have an effect on pulse timing and velocity at the collector. Bends can also dictate reversion (exhaust gasses going back into the exhaust port). Of course the collector design (layout and merge angle) has a lot to do with scavenging; a rotary collector will always provide the most equal scavenging from cylinder-to cylinder. If the scavenging is not optimized and equal, during the intake stroke you will have varying levels of exhaust gas contamination during cylinder fill (air & fuel). This can lead to different cylinder temperatures (EGTs), burn efficiency, knock threshold, etc...
10-13-2018, 07:51 AM
. I never ever asked Vektor for any discount, I only asked if they would be willing to give me a full refund if my dyno results weren't reasonably CLOSE to theirs.
