His last post on rs246 on the install was positive http://forum.rs246.com/viewtopic.php?f=35&t=110477&start=225#p710876
But a bit of a low key ending for sure. He’s probably been busy. But looks like the car runs as it should.
cleanest install yet, I’m sure it’s running great.
Also noticed his 3k to 8k of 6.2-6.3
for reference Sakimano and Mistro listed the below numbers in their comparison.
3rd gear vagcom measured 3k to 8k, (Saki)8.5 seconds and Mistro was about 7.5
Sakimano - 08 RS4 bone stock with no passenger and 1/2 tank of gas, never carbon cleaned
Mistro - 08 RS4, JHM 93 tuned, JHM Stage IV clutch+LW flywheel, JHM LWCP, piggies, JHM intake spacers, ECS Hpipe, ONE passenger (ME 245 lbs), 1/8 tank of gas, carbon cleaned 10,000 miles ago
Wow that’s a big jump in performance. For 7800$ that’s a great jump in performance for the money.
yep
been uber busy but i promise i will finish up this thread soon.
car and supercharger are doing fine, almost 5000 miles since the install and zero issues.
still need to sort out the foglight out warning light just not had time, for some reason the resistor i got in the kit doesn’t work.
i grabbed a quick vid last night of a 3-8k run, seem reasonable?.https://www.youtube.com/watch?v=-Ol9FdQ8vT0
want.
that’s very very fast
about 6.1 seconds according to my stopwatch. Not entirely accurate since I’m starting stopping, so lets say worst case 6.3. That means you’re 2 full seconds faster than stock, and a little over 1 full second faster than tune/full exhaust. Pretty compelling.
Considering the delta between stock and tune/full exhaust is about 40 whp and 30 wtq, you’d have to surmise that this is about 90 whp and 70 wtq over stock…with stock being around 320/270 that means around 410 whp and 350 wtq. That’s right where the kit should be so that looks great.
Would love to see you race
a) a stock RS4
b) a MRC full bolt on RS4 (MRC tune, full milltek)
c) a JHM tuned full exhaust RS4 (there were a couple of guys who got tuned, and one of them had an EBwerks exhaust…which isn’t exactly a great option but is still 2.75" at least.
Really nice install that performance run looked great too. The jhm stage 1 kit is really a great performance boost for the money.
Pretty much exactly 6.2 seconds. Very impressive performance. Thanks for the video!
I do believe with supercharged setups a “proper” exhaust is required to get all the power out of it. Can’t imagine why MRC think pushing about 300 horsepower through a considerably-less-than-2.5 inch Milltek is a good idea.
On the other hand, for an NA car that makes roughly 200 horsepower per bank a 2.25-2.5 in exhaust is sufficient. There may be a couple horsepower in going larger but not to the extent that the engine is craving for it as it would with a supercharger.
My car picked up basically 20 hp and 20tq by going 2.75.
Compared to stock with 4 cats I imagine?
By the time you compare it to piggies (and possibly an x-pipe in the stock exhaust) the difference won’t be that significant. ~200 horsepower through a 2.3(?) In. pipe isn’t leaving much on the table really. Particularly because the stock manifold are excellent.
Yes, compared to stock. I also have 2 cats in the main cat position.
Your rationale is that 2.36" is sufficient and the stock exhaust isn’t leaving anything on the table for NA. Reality says otherwise.
JC, You assume a lot of things and I like that you rely on math and calculations, which I also enjoy, but you have to look deeper than that.
You’re assuming the 2.3" piping isn’t crushed in sections and there aren’t shitty bend that adversely affect flow. Most of us know that there are so in reality you could gut the cats and add an X-pipe but you would be trying to polish a turd.
The JHM exhaust isn’t successful based on it’s diameter alone, I think we can all agree on that. The success of the system really depends on the designer knowing the engine and the concepts of exhaust tuning…just like we always discuss with their B6/7 S4 headers.
I feel that the gain of a 2.75" exhaust is actually decreased when a car is supercharged.
For example:
Going from an OEM to a full 2.75" catback NA will have a larger gain than
Going from an OEM to a full 2.75" catback while supercharged.
I’m not saying the increased size isn’t needed for efficiency, but the delta is larger while NA.
This is apples to oranges, but take not of the B8 S4…headers and exhaust add almost nothing.
This is one of the companies that you were arguing for in your other thread.
The fact is they really don’t care about making power, they just need their dyno to show that they make power or increase performance. As long as the guys in Europe stay happy buying dyno sheets, then all is good and MRC will pump their custom tunes, P&P intake manifolds, cold air scoops, and undersized exhausts…they should just hope their customers don’t have a run in with a JHM car because it’s usually pretty embarrassing.
The B8 S4 bears this out. The exhaust seems to deliver very little gains.
Supercharged, I believe one of the fastest times on a JHM stage 1 car was running a stock catback and JHM downpipes. Trapped 118.
Same goes for the APR test car…didn’t it have stock catback? Ran 11.15 @ 125
Yes, pretty much. Rather a well designed 2.36 inch exhaust than a crappy 2.5 or 2.75 inch one (not the JHM obviously before you jump me again - there are more “large” options i.e. Supersprint)
The stock Audi exhaust really is quite good. They will have spent a lot of time designing that component - albeit with multiple targets not just outright performance. A lot more thought went into it than with most aftermarket solutions. It’s not a “turd” by any stretch of [euroswagr’s] imagination. The Audi main cats are also very good, no reason to replace those at all.
[quote] the stock exhaust isn’t leaving anything on the table for NA.
[/quote]
I didn’t say “nothing”. I said not much. I can believe your JHM exhaust gained you about 20 horsepower. I also believe at least half of those gains are due to the absence of the 400cpi primary cats. Those are by far the most restrictive component. Every time I see them I can’t believe you wouldn’t gain >10hp without them on a 400hp engine. A stock exhaust with an X-pipe in the right location (I’m sure JHM did considerable research in finding the optimal spot for the X) will not leave much left to be gained by increasing the pipe diameter. This is guesstimation territory but I would say maybe 5 hp. Really depends on the precise design of the exhaust, it’s a complicated science where you need both velocity and low (but not too low) backpressure.
Anyway, looking forward to see what my car gains without the precats. I just picked her up and she certainly sounds better, but was stuck in traffic pretty much the entire way home.
Bottom line OPs car runs great, sorry for the accidental derail.
actually, not anything has been contracted to create a new word, and that word is…
…NOTHING!
I got that much, but I didn’t say either of those did I?
[quote=myself]the difference won’t be that significant.
[/quote]
How you went on interpret that as zero or nothing or not anything I’m not quite sure.
Dude, you like to think out loud…but you can’t accept being wrong. You will argue in circles just so you don’t “seem” wrong.
So you said the stock exhaust would be sufficient without cats and an X-pipe
Now you’re saying a well designed 2.36" exhaust would be sufficient, which is it?
You also still haven’t touched on your rationale about exhaust size with a supercharger. You are guessing and assuming everything, but testing has shown your guesses are incorrect…but you still argue.
Did you just contradict yourself in the same post?
[quote=JCcan’tbewrong]The Audi main cats are also very good, no reason to replace those at all.
[/quote]
[quote=JCcan’tbewrong]I also believe at least half of those gains are due to the absence of the 400cpi primary cats. Those are by far the most restrictive component.
[/quote]
I think he meant pre-cats when he said primary cats.