I can climb in the engine bay of my 95 Impala. The Solstice actually has enough room on the passenger side that a small child could pass through from top to bottom when the stock exhaust manifold is removed.
You can also fit about 4 human heads behind the grills.
Think of a header as a musical instrument, because it flat out is. Exhaust velocity is controlled by pipe length, volume and diameter along with how transitions merge and tubes collect.
Bla bla bla 4-1 headers are this and bla bla bla Tri-Y headers are that.
When a header is designed AND built right it will always produce more performance than a stock manifold will. When a header is just slapped together then it will usually still make power, but nothing worth the performance for the effort.
Everyone likes to cite a cliché for what design does what best, but the fact of the matter is engine bay limitations and exhaust location dictates more about the design than any other factor.
A 4-1 shorty header works great for a daily driver/drag racer, but I have seen a properly designed collector make more horsepower in itself than an already good overall designed header. I have seen headers that look almost identical have as much as double performance gains from just primary length and collector detail. And I have seen what looks like a waste of time, joke of a TriY/4-1 design, 47 chromosomes having ugly header produce 20 HP over stock on a 4 cylinder N/A engine with no loss below stock at any rpm.
A long 4-1 works great for road race applications and when built well doesn’t really take anything away from the bottom end.
A Tri-Y has the advantage of actually reaching the maximum performance and boosting up low end power too. It’s just difficult to get it right in the first place and for the most part you don’t see major changes or differences between one company’s product and another.
I think that the devil is in the details, but the details are dictated by the confines of the platform. That SR20DE header that makes 20 HP has been validated by Nissan themselves and literally tuned to cc’s in tube volumes and validated with both real world flow-bench and CFD software. A lot of the details of that header could be carried over to the LE5 (2.4L ECOTEC), but knowing what details are important and what ones are not turn out to be a difficult-if not impossible task. As more products come to market hopefully the competition in business produces better and better performance for what’s available. It’s just not going to happen overnight.
__________________
-Adam Chant
SCdyne Performance Engineering "Tune it or lose it!
Adam,
some very good points. However, flow bench testing of a header, and flow capability in general, has absolutely nothing to do with thermal dynamics or scavenging. Many people mis-understand scavenging for flow.
The Exhaust velocity can definitely be increased from simply using a true "merge collector" such as Burns Stainless offer. But, the difference in price to add just theis collector is $150.00. It's available if anyone wants it but in my opinion, it would be a huge waste of money on the shorty header. Maybe worth doing on the long tubes, but as you stated, the confines and limitations of the engine compartment dictate more in the design of the header than anything else. In other words, you wont feel the difference on the street.
In a nutshell, you want flow for the intake system and scavenging for the exhaust. Two totally different characteristics.
A properly configured CFD will in fact calculate scavenging, but only based on the model used. However taking that 3D model of a header and duplicating it in the real world is another level of complexity most manufacturers cant and don’t address. So you are back to design and tooling limitations and confines of the engine compartment for the most part.
I could debate both the actual cost and benefit of a merge vs. formed collector too, but it’s again a factor of the above issues. Maybe you could also build a miter cut merge header and run it on a dyno with your current design and see how much difference it makes. I know that in the 2.0 LSJ it results in a difference of twice the performance gains of similar shorty header designs (10vs20HP gain), but that’s a supercharged engine. It’s possible you can work in the miter to the current design as another bend step. Then it’s a matter of welding from that point on and the difference between a header that makes 8 HP over stock and one that makes 14HP over stock for the same price.
I’m not being presumptuous about anything I’m doing either I’m making suggestions that can potentially help things along. A little extra work now is less expensive than a lot of hassle later.
__________________
-Adam Chant
SCdyne Performance Engineering "Tune it or lose it!
A properly configured CFD will in fact calculate scavenging, but only based on the model used. However taking that 3D model of a header and duplicating it in the real world is another level of complexity most manufacturers cant and don’t address. So you are back to design and tooling limitations and confines of the engine compartment for the most part.
I could debate both the actual cost and benefit of a merge vs. formed collector too, but it’s again a factor of the above issues. Maybe you could also build a miter cut merge header and run it on a dyno with your current design and see how much difference it makes. I know that in the 2.0 LSJ it results in a difference of twice the performance gains of similar shorty header designs (10vs20HP gain), but that’s a supercharged engine. It’s possible you can work in the miter to the current design as another bend step. Then it’s a matter of welding from that point on and the difference between a header that makes 8 HP over stock and one that makes 14HP over stock for the same price.
I’m not being presumptuous about anything I’m doing either I’m making suggestions that can potentially help things along. A little extra work now is less expensive than a lot of hassle later.
I'll jump in since I am doing the fabrication on the headers.
Having a merge collector would be ideal, even doing as you suggested trying to incorporated it into the bent parts during fabrication, but with the limited amount of room and not having a tighter bend to facilitate the procedure it's just not going to happen, at least not with these short headers.
When we bend parts for headers there is a certain amount of space between bends that we can do nothing about, (just the capabilities of the machine )
Our goal is to have a quality built header that will bolt up to the stock converter and that is not outrageous in price.
I know Burns has a short merge collector, but that would still be next to impossible to fit into the design that I have come up with, with the limits that I had to work with and stay within our target price. I could build one, but the price that we would be asking would not go over well for the majority, especially for what the limit that a short header is going to be capable of.
Best possible gains are always best when you have the space to do it in.
Like my partner had said you brought up some good points, no disagreement there.
Thank you for your input.
But what about those of us that do not want the converter, why can you just re-designed that header to bolt into the pipe that goes back to the muffler?.
The reason, I do not want to do any cutting just unbolt the old OEM header and converter and bolt on yours.
That is why I was showing this header to you before.
__________________ Aggressive GXP at $25,995.00 shipping of $600, Manual Transmission.
Options:
Air, $960; Chrome Wheels, $545; PCQ, Premium Package (Leather), $525; Radio, 6-Disc with MP3, $495; Monsoon, $395; Premium Acoustic Headliner, $150; and Sport Metallic Pedals, $115; all totals $29,180.00. No XM/OnStar and NO Spoiler. MODS (RKSport/Magnaflow dual exit exhaust system, K&N filter, Ventureshield.
First 1000. Aggressive with everything, NO XM/OnStar. SOLD
~~~~~~~ NASSOA
Founding member
~~~~~~~
But what about those of us that do not want the converter, why can you just re-designed that header to bolt into the pipe that goes back to the muffler?.
The reason, I do not want to do any cutting just unbolt the old OEM header and converter and bolt on yours.
That is why I was showing this header to you before.
We are going to be doing a version just for that.
We have basically (6)different combinations that we will offer, (3) in both primaries sizes.
We are looking to have the most available and easy installations as possible, with out any cutting involved, and the way this car is set up, it will not present any problems in accomplishing that.
We will be reclassifying our headers. So the first that we have shown to be labeled as a "shorty header", next will be "mid length"-that will bolt up the stock exhaust with the stock converter removed, then the "long tube" that will require our cat-back exhaust so again there will be no cutting involved.
The "mid length" & "long tube" will have the option of having a high flow converter put in with our cat-back exhaust, which by the way both of these "mid length" & "long tube" headers will be an "off road" version.
If there are any other combinations that we may have missed, please feel free to put forth your idea, as we are looking to produce what the people would like to have.
The reason for me asking for that feature is because I am buying the RKSport dual exit carbon fiber valance and dual exit exhaust, that exhaust comes with a new pipe from the converter down. I just do not want to be cutting into a brand new item I just purchase.
__________________ Aggressive GXP at $25,995.00 shipping of $600, Manual Transmission.
Options:
Air, $960; Chrome Wheels, $545; PCQ, Premium Package (Leather), $525; Radio, 6-Disc with MP3, $495; Monsoon, $395; Premium Acoustic Headliner, $150; and Sport Metallic Pedals, $115; all totals $29,180.00. No XM/OnStar and NO Spoiler. MODS (RKSport/Magnaflow dual exit exhaust system, K&N filter, Ventureshield.
First 1000. Aggressive with everything, NO XM/OnStar. SOLD
~~~~~~~ NASSOA
Founding member
~~~~~~~
The reason for me asking for that feature is because I am buying the RKSport dual exit carbon fiber valance and dual exit exhaust, that exhaust comes with a new pipe from the converter down. I just do not want to be cutting into a brand new item I just purchase.
I plan on doing the same thing... and I'd like to ditto the part about not wanting to hack the new exaust.
The reason for me asking for that feature is because I am buying the RKSport dual exit carbon fiber valance and dual exit exhaust, that exhaust comes with a new pipe from the converter down. I just do not want to be cutting into a brand new item I just purchase.
Well then, what we are planning to offer should be just the answer for you and those looking to do the same thing.
We will keep everyone updated as we make progress.
Will this shield be required when installing your headers?
No, the heat shield will not go back on. It will not be required any more. The stock engine cover is the closet part to the headers. It is on the car now and is doing fine. my partner has drove pretty hard a couple of times to get the headers hot just to see if it would damage the stock cover, but so far it is withstanding the initial heat given off after a spirited drive! ( ceramic coating benefit )
We have designed another engine cover to open up the engine bay and show off the headers even more, plus we were not sure at the time if the stock cover would take the heat.
For those interested in something different, our engine covers will be available in different materials and finishes, ( Stainless, Aluminum, & carbon fiber )
you can see the prototype engine cover in the pictures of the headers at the top of this thread.
