MORE SRT-10 FILTER DYNO RESULTS

[Y2K5SRT]

No pics right now, as I have to get on a plane in a few hours. I promise to post graphs when I get back. In a nutshell:

The Green Filters, as I suspected before, don't fit. They look IDENTICAL to the factory filters in size, yet it is almost impossible to get the airbox cover on with those filters on. Why? The factory filters have a lot of "give", especially in the orange rubber material at the ends. These Green filters have a MUCH harder black rubber/plastic end that does not allow it to "wedge" into place like the factory filters. Nonetheless, Frank tried them out with his airbox barely closed. He was not particularly happy with any of his numbers, but here is how they played out:

Stock filters: 427.4 rwhp and 469.0 rwtq
Green filters: 435.8 rwhp and 475.5 rwtq
K&N tube and filters: 442.2 rwhp and 478.1 rwtq

We think part of the problem with his car is that Frank tends to "cruise" it more than some of us (not as much WOT), and thus his computer has adjusted accordingly. We did not do any power disconnects before or after any dyno runs. Next up was Mike with his black SRT-10. No reason to bother with the Greens, as we already knew they wouldn't fit properly. His results:

Stock filters: 435.5 rwhp and 474.1 rwtq
K&N tube & filters: 451.8 rwhp and 489.6 rwtq

Next up was Allen's red SRT-10:

Stock filters: 436.6 rwhp and 473.7 rwtq
K&N tube & filters: 452.9 rwhp and 493.0 rwtq

Bottom line? The Green filters are probably good for a decent gain (~10 HP), but the fit isn't quite right. They are definitely a better price and would fit fine if you don't mind possibly having to grind down part of your airbox ribs. The K&N system just seems to be a MUCH better fit and also delivers the power to make it all worthwhile. Also, seeing that "K&N" logo when you open the hood at least tells folks you aren't satisfied with a stock car. I will try to post graphs when I return, but hopefully this should give you some more stuff to discuss!

Once again, our thanks to JonB at PartsRack for the very generous loan of these various filters for dyno testing. At least three more K&N orders will be ringing in from Kansas City!

Chris

PS. My crappy ol' SRT put down 461.7 rwhp and 502.4 rwtq with the K&N's yesterday - no stock filter runs for me!

 

[ARMORGOD]

Chris,

Thanks for the objective test of the K&Ns. I'm sold. I don't know what you do for a living, but if you ever loose that job you need to give Consumer Reports a call.

 

[treynor]

Chris - that is very interesting. The K&Ns are showing a consistent 15 RWHP gain.

 

[Joseph Houss]

Great Job Chris! Those are REAL healthy numbers!

Anyone know the true driveline loss on an SRT-10?

 

[Casey]

Wow, 15 rwhp gain with filters!

 

[Viperfreak2]

Gotta say, I'm impressed with the K&N setups numbers. I'm a little confused about Frank not being happy with his numbers. 442 rear wheel HP isn't good? 12% driveline drag would make the engine putting out close to 500hp. 15% close to 510. For a gently driven car, not too bad.

 

[Vipera Russelli]

Thanks Chris! You're a real asset to all of us on the board. Nicely done.

 

[LittleFish]

great job guys, I know Allen was excited with the results! Allen, what was your top speed on the dyno?
dave

 

[Frank 03SRT]

Thanks Chris! You're a real asset to all of us on the board. Nicely done.

You think that is good --- you ought to see how good life is IN the KC VCA. I'd follow anyone for free pizza, pop and dyno. Pretty sweet.

 

[Kai SRT10]

Those are some crazy numbers for just changing filters and tubes.

Who needs turbo chargers? Keep on doing these 15 horsepower mods, and we'll be up to 1000 hp in no time.

I just ordered my kit from Parts Rack today.

Thanks for all the good information.

Just hope that I will still be able to drive my car in the rain without drowning the engine.

Kai

 

[Phoenix SRT]

Filters and smooth tubes (is that what we are calling the K&N snorkle to which the filters are attached?) are a simple and cheap way to get another 15 or so HP/Ft Lbs. So cheap and simple, in fact, it is hard to believe that the factory wouldn't do it in the first place.

So does anyone know why on earth the factory didn't put a better filter system on the car right off the bat? I think I read recently on this board that the K&N system is noisier than stock, especially at WOT, and that is the reason. But, how in the heck much noiser can the the front end of the induction system get? It's hard to imagine that it could make much of a difference, given how loud the Viper is anyway. But then again, I've not heard an SRT with K&Ns. I will soon, though, as I just ordered 'em.

It really seems bizarre that the factory would, in essence, decide, "well, naw, don't need no stinkin' extra 15HP...got 500 already and that's plenty." There must be a reason.

 

[Frank Parise]

I wonder how much of the 15 rwhp gain is due to the K&N filters and how much is due to the modified K&N snorkle. Is it possible that most, if not all, of the gain is simply from the filters? Most of the Comp Coupes I am aware of are already using K&N filters in place of the stock filters. Before purchasing the K&N snorkle, I'd like to know where the gain is really coming from. Can anybody help?

 

[SnakeEye]

No idea why a smoother tube design wasn't used from the factory. However, I would think intake noise on WOT might have been a consideration as well as the effectiveness and efficiency of the filters themselves in selecting the original equipment components. Not withstanding K&N’s good reputation, how does the K&N filter stack-up in this particular application when compared to the factory units on filtration? Always interested in (safely) adding more power especially at $20/hp. That's tough to beat.

 

[Frank 03SRT]

Chris explained this at the Dyno day. The current "snorkel" has a big proboscis who's intent is to eliminate noise. It also causes turbulence which he explained could cause restriction. That is the assumption, at least.

But, it DOES work. I am a believer, and ordered one today from Parts Rack.

 

[ViperRay]

I was there and I am a believer in the fact that there is some added HP from these filters/tubes. I DO believe we are letting more particles into our engines with these higher flowing filters...I only hope it's not enough to affect the engine in the long run. Since K&N has been around a while and I haven't heard of any problems attributable to their filters, I guess they don't cause any obvious problems.

Just one more thought if I may play Devil's Advocate here. As I came along a bit later in the day, I did not see every run. I do know that most cars showed increased HP and torque with the second run. This is obviously due to the computer learning a more aggressive throttle application and adjusting accordingly. Chris already pointed out that he did not disconnect the computer before each run; this does create a problem in that the additional HP with the filters may in part have been due to additional computer learning. I would feel better from a scientific standpoint if I knew that the tested cars had at least 2 successive pulls with the same numbers before putting on the filters (ie: the computer was done adjusting the various parameters). This may in fact be the case but, as I said, I got there later and do not have the benefit of this information...but it is relevant.

Speaking for my own GTS for example, my torque went up 14 ft.lb. from the first to second pull to 492 (HP increased 8 to 440). Would a third pull have shown a further increase yet? I did make a 1 hour highway run to the Dyno shop from home which exacerbated this tendency I'm sure. Some of the Dyno gurus can respond to this but I would guess there would be a smaller gain still for another pull or two as the computer continued to hone in on the best mixtures. So I guess I'm wondering if we can take the 15 HP gain as gospel.
Having said all that, it's obvious that the tubes provide more laminar flow from the design and the K&N filter lets more air through so some HP gain is inevitable. Jon will therefore be getting another order this week.

Chris is due a round of applause for his efforts with this project not to mention that it was great fun in the process!

Sorry for the long post

 

[Frank 03SRT]

Good point on the numbers always going up at the second run. That's happened to me every time, --- but not the third time --- I have tried it twice before. Notice mine went up on the third time, which is what convinced me.

 

[Kai SRT10]

Just one more thought if I may play Devil's Advocate here. As I came along a bit later in the day, I did not see every run. I do know that most cars showed increased HP and torque with the second run. This is obviously due to the computer learning a more aggressive throttle application and adjusting accordingly. Chris already pointed out that he did not disconnect the computer before each run; this does create a problem in that the additional HP with the filters may in part have been due to additional computer learning. I would feel better from a scientific standpoint if I knew that the tested cars had at least 2 successive pulls with the same numbers before putting on the filters (ie: the computer was done adjusting the various parameters). This may in fact be the case but, as I said, I got there later and do not have the benefit of this information...but it is relevant.

I have dynoed my car several times. I will always do several successive pulls. I have not noticed a big change in hp or torque on subsequent pulls. In fact, on my latest dyno, my second pull was 2 hp lower than the first.
So, I don't know that it would make a difference.

Kai

 

[GR8_ASP]

Great info Chris. You gotta love real data

On the noise aspect the K&N is definitely louder than stock even at idle. From the front of the car you can hear the air rushing sound (note that standing in front of my car and listening is not adviseable). I am not sure I would characterize the noise as wanted or unwanted. It is not clearly a good or bad sound, and if it results in more power then so be it.

Here are a few pictures from my installation. As you can see the stock airbox is used and there should be NO impact on water ingestion/driving in the rain from stock.

 

[CAS]

My guess to why the factory doesn't supply K&N's is because of the required maintainence of the aftermarket filters and a potential owner having to perform that. They don't want the liability. (IMO)

 

[GR8_ASP]

Clint, I am sure that is a factor. But they did install K&N's in the ACR's and GTSR's I believe. These are much easier to remove and clean/reoil than Gen I/II.

 

[CAS]

Clint, I am sure that is a factor. But they did install K&N's in the ACR's and GTSR's I believe. These are much easier to remove and clean/reoil than Gen I/II.

I'll be damned you're right about that, I forgot that the ACR's and GTSR's came w/ them. Maybe DC figured the new Gen III owners demographics were such that they weren't tech saavy enough to do it.

 

[Viper Specialty]

I would say that if anything, it serves as a future modification the factory can do to new SRT's in order to show "HP Gains" in future years, etc. The intake and exhaust system in the SRT cars is very restrictive, and quite a large amount of latitude exists for future HP jumps without having to actually "touch" the engines.

 

[Viperfreak2]

How about the theory that it was purposely tuned down to produce the magic 500 number? Also, it saves money when not spending the amount of time to get the best results. Look how much time it took for K&N to 'get it right'. DC saved tons of money not having to find the extra ponies.

 

[Paul Hawker]

Believe it is a Federal noise standard issue. SRT is right on the line, as to the standard. In order to get more power, the noise standard gets in the way for the OEM, however aftermarket does not have the same restrictions.

Lots of comments on the K&N being more noisy.

Same goes for exhaust. Aftermarket parts can gain power, but are significantly more noisy.

All the new supercars sound like whispers, compared to that raw, wide open sound of power, many of us desire.

Way to go K&N. Looks like a great product.

 

[Black SRT]

Chris,

Thanks for the research! JonB has me back-ordered.

Regards,

 

[SCLSSRT10]

The Illinois club had a dyno day today. 3 SRT's were run one stock filters with a corsa exhaust turned 449rwhp tq?, second BONE STOCK? (you know who you are) turned 453rwhp 493 tq, and mine with Glass Pack mufflers and the K&N filters turned 442rwhp 507tq . I am not sure if the Glass Packs are such a good idea after all and looking at other numbers posted earlier. But they sure sound good.

 

[Daniel Cragin/DC Performance Inc]

We have had no problem fitting the GREEN filters on the SRT/10. They are a tight fit but will go in perfectly with a little patience. Our initial testing on the pre-production K&N
FIPK system showed very little increase in power, there was also a very loud whistle associated with the new balance tube.
Obviously the production units appear to be working well, and if John is selling them they must work.

 

[ViperRay]

Seems to me like intake and exhaust is less restrictive in general on stock SRT compared to Gen II so less HP gain or variation with these mods...just an impression, I could be wrong.

 

[ViperRay]

I would like to know how much (if any) power headers add.

 

[GR8_ASP]

Dan, I made a separate post on this. If you had a loud whistle you probably had the same problem my K&N had. That is the PCV make-up air port was flashed over. This causes the crankcase to operate at a greater depression than normal and increase the PCV flow through the PCV valves and into the intake.