dyno

we know that the main difference between these headers is that

A- Renntech is a quasi-4-in-1 and fits to stock collector/cat , therefore last diameter is about 47-50mm



B- Kleeman is a true 4-in-1 , with collector enlarged to about 65mm and therefore requires new piping to fit stock or race cats.



at first we'd think that's better performing B ... but is there any evidence?

I'm wondering this issue especially after so good results achieved with log-style headers .. as if it were that decreasing counterpressure with larger collectors will not yield what expected

thanks for contributing

rarfinancial

but I have Renntech header and they do not look like that,

dyno

if so, .. please post the correct image
I do not have them, and picked the image from GMP performance, here:
http://www.gmpperformance.com/index....catList&CID=50

in any case, proper topic is not the image issue ..

Andy0331

Those may be Renntech headers, but they certainly appear to be for a V6.

JKK

I worked at Dinan Engineering for almost 9 years and have a lot of respect for Steve's knowledge. I attached the address to his M3 exhaust white paper because regardless of the engine, the theory remains the same for all. I think he does a good job explaining what’s important. You would have to do a flow compression to see which one allows the engine to “breath” better to determine the superior design. Hope this helps.
http://www.dinancars.com/whitepapersFile.asp?ID=3

Kyle M

If you look closely there appears to be a fourth hole?

dyno

I'll read with interest what's in your link but ...theory is clear; our Mercedes is something .. specific
Theory, in general, is written without taking into account subsequent Pollution regulation induced modifications in modern engine's exhaust management systems.
.. hope sounds clear what I mean.
one word will help: EGR = exhaust gas recirculation system.
but this is no the present topic.


4th hole: again... even if this is not the topic, just click on the link given and would appear also to a non attentive eye




came on guys, WANTED is the opinion of those that had the opportunity to test both solutions: stock vs unrestricted short header, regardless of its brand name. and, possibly, excluding all cases of hard mods ... say, still with stock cams

James@Creative

Here is a pic of the AMG55 RENNtech headers

jangy

I'd still argue that shorties are shorties nd long ones aren't. Doing a little quasi playing with the lengths does NOTHING on the dyno. That is why I was so happy with the logs. Either way, you are leaving about 10hp by not going without the primary cats.
Now, the question to ask is what happens when the thing cracks. Will the vendor / shop step up and replace them quickly with new ones? That is key to me. I can't stand those that don't stand behind their products and workmanship. All I was worried about was getting the best quality at the best price. Well, I got it. I got RennTech parts and paid rock bottom pricing for it. Unfortunately, something went wrong and when the dust settled, there was no tuner or shop to be found. You may be happy now, while the prices are low, but you'll be pissed you ever went that route when your car is trashed.

rarfinancial

If the question is, are the shorties better than stock manifolds?, then I will say YES you will see, hear and feel a differance Hey Jangy, Famoso?

dyno

good, we are now something further. you say that
-LOG STYLE or SHORTY makes quite no difference
(and that with CATS off is better than with cats on. no question on this)

so, I'm allowed to infer that ONE better difference of modded Shorties versus Stock is because of their larger piping diameter at engine's outlets.

.. but we still miss the main issue: what about LARGE COLLECTOR/OUTLET vs STOCK COLLECTOR ?


PS:
the "after service" issue: if you are concerned with this, then better remain STOCK. ... in my long enough experience I can tel you that when the problem get serious, After-market will NEVER go hands-in-hands with After-Service.
We are a bit off-topic, but I want also tell you that for example in Germany you can buy a specific insurance coverage together with the tuning service. BUT: your car is not entitled if it has more than 30k miles, and you cannot mod it DIY !

deaguero

Very measurable! I have the Floored Fab/VRUS "Shorties" and they gave me +28rwhp from the pre dyno to the post dyno. Thats a fact!

DKM

Can I throw this out? Are you sure you got 28rwhp because of headers? Or did you get 28rwhp because of outside weather temps, the car wasn't as heatsoaked, the correction factor on the dyno was more, and so forth.

I'm not saying you didn't make the power. I'm just asking the questions.

I have a supra that will vary 50-60rwhp on any given day with all things constant. It'll make 1090rwhp and the next week it makes 1160rwhp, then the next week it make 1140rwhp. So...with that said...was everything constant?

dkm

DFW01E55

Can you post the dynos?

deaguero

dkm: We ran both the dynos (a pre dyno run without the Headers and a post installation Dyno with the headers installed) in Arizona (phoenix) on back to back days.
The conditions were almost exactly the same with 102 degree outside temps and the humidity at about 15% both days. We ran them both in the morning around 10:00am and this was the best we could do with the early June summer conditions in Arizona 6/05/2007 to be exact. The promise from Chris at Floored Fab was "A gain of 20 - 25 HP gain or no charge. Man was I happy after the dyno confirmation! Aside from the dynos, The car really has lots of top end pull as attested from the "Fontana day" in October since my E55 was the 3rd fasted AMG that day out of about ten or so cars both E55's and E63's. Regards!

JKK

Kleemann Headers on the 2007 E63 with engine management software and high flow cats made a big difference. The car feels faster and sounds great. Don't know about the headers by themselves.

Jrocket

Any dyno graphs or track times to show the improvement your talking about?

IngenereAMG

One of our clients (who posts on the SL55 area) has our ECU work and Renntech headers. He posted a dyno of 486hp @ the wheels.

Jrocket

Looks like he better find a dyno that doesnt lie.

Fleebee

+1
that's a little too much to swallow.

JKK

I don’t know, however the owner is very in tune with his vehicle. He tracks it (Thunder Hill, Sears Point, I-80, etc.) and was really happy with the upgrades and definitely noticed the improvements. I have a friend that has a couple of Dynapak dynamometers and I will see if we can do a few rips. I’ll post ‘em if I can get ‘em.

JKK

I have done the Kleemann headers on both the E55 and the E63. Each design is different. The E55 headers have long tubes and the E63 has the short, same company with both versions. The issue is room. The E63 has less room than the E55 and so the compromise is going with the short version (due to space) with larger diameter. To my knowledge, best case would be equal length tubes, larger diameter, with a collector that is smooth and doesn’t create any turbulence within the system. With this set up you can “tune” the exhaust flow and actually create suction to help the intake system breath better. Better breathing = added hp/lbft. With any aftermarket tuner there will always be compromises. There is only so much physical space and therefore only so much room for improvements.

jangy

You are finally getting my whole point. What good can it possibly do to make the longest tubes, if they will met up with the primary cats anyway? If I were going to cut the cats, I'd go long headers all the way. The FACT that ANY shorty header shows about 10 less HP than the long type tells me that the diameter is indeed the advantage. It allows the motor less restriction on exhaust AND it will pass Cali emissions. I'm getting the VRP ones because they are the best compromise, including price. $1550. Find me a better performing header for $2000 (max) and I'll switch. If not, shorty VRPs it is. Also, keep in mind why we need the headers? It is for top end on the 55s. We have grunt. I'm adding pulley and TB, which will get my bottom end even more. That is where the header compliments it all. It lets it spin more freely. I honestly only expect the difference to be from about 1/8th mile on. Anything more is cake for me.

Jrocket

What headers pass CA emission's?

deaguero

I am prety sure the Log style (VRUS/Floored Fab) will pass. There is practically no diff from the external appearance of the stock manifolds.
That's why I moved back to Cali....