Tomyx Intake for Dummies
 

Myself being the dummy here.

Alright, so it says 19HP proven gains with 'mods'. You explained to me that the stock exhaust&filter will hinder the intake. I get it. But there is so much more I need to learn. :o


Questions:

What kind of filter was used on the dyno car? (before after??)

A more appropriate freeflowing exhaust.. I LOVE the sound of the stebro. But I have listening to your custom set up on the online clip. I think it sounds alot better. I REALLY want to get to reading, so I can hear yours in person (internet clips leave alot to be desired for exhaust I think).

Would the Stebro catback system fit the bill for (freeflowing)?
Would yours fit the bill BETTER?

Would the answer change if I got lans S/C?

Would this still be an appropriate mod?

Re: Tomsvx Intake for Dummies
 

I could be wrong, but I don't think you can get lan's s/c kit anymore, unless you find one used. As for the intake, I think it will be a benefit at any stage of modification. I can't see it hurting, in any case. As far as the exhaust goes, without any AB testing done with a dyno on any of these systems (that I know of), I think you need to let your ears make the decision. The one thing most agree on, though, is that the front portion of the exhaust (the cats) either need to be left as they are, or at least have resonator in the place of the front cats.

Of course this exhaust information all goes out the window if you go FI. Then standard rules apply. Large diameter pipe, very little restrictions, etc.

Re: Tomsvx Intake for Dummies
 

One thing I will ad related to the intake is that In my mind, it is advisable to use the stock airbox with the stock ecu, even with the tomsvx intake. I don't know if it has been looked into in our cars, but in maf equipped imprezas removing the stock airbox, or even cutting off the resonator as described in other posts, tended to make the car run EXTREMELY rich at a certain rpm range (around 2K, I believe).
http://forums.nasioc.com/forums/show....php?t=1471819
Now granted they are saying that this mostly affects 05 and uop imprezas, which probably don't even use an ecu like ours, but I suspect a similar situation likely with ours. Unless somebody with an afr gauge and a custom intake cares to prove me wrong.

Re: Tomsvx Intake for Dummies
 

^^ I knew that link would go to williaty's thread... The guy's information is quite robust; it's good to have someone around that forum who reports legitimate results from legitimate tests instead of the typical butt dyno pilots.

Re: Tomsvx Intake for Dummies
 

That is a problem with the four cylinder engines, due to the firing order, that has overlapping intake pulses on each side. The eg33 has alternate firing side to side. My 97 Liberty has three resonate interferance pipes in the air delivery pipe to try to reduce the effect.
Its the same reasion that they have that "blat blat" exhaust sound, like a big twin. :)

Harvey.

Re: Tomsvx Intake for Dummies
 

So does that mean that our cars engines have no similar traits as far as the resonator? I am still skeptical. Why, then, would Subaru bother to include the resonator if it didn't serve some function?

Re: Tomsvx Intake for Dummies
 

He was saying that the 4 cyl boxers have as many as 3 resonate points, while the flat 6 seems to only have one resonate point, and that is why we have the resonator where it is. Removing our resonator does not effect the flat 6 as much as it does on the flat 4's. Or something like that.

Re: Tomsvx Intake for Dummies
 

OIC:)
Thanks for clearing that up.

Re: Tomsvx Intake for Dummies
 

No prob, I'm pretty good at seeing all possible angles of one statement.

Re: Tomsvx Intake for Dummies
 

All of kevin's original dyno tests can be found --->HERE

fwiw the car that was put on the dyno had a custom exhaust from manifold back and a very mild cam upgrade. The 19awhp gain WAS done only by the intake, and not a culmination of all the modifications at once, as the upgrades were installed by the previous owner (As stated many times in kevin's original testing and our for sale threads)

on a bone stock car, it wont have quite the same impact, as the intake isn't really a bottleneck untill the exhaust is freed up a bit. but if your planning even very minor mods, it certianly is worth doing. If you're planning on going with lan's sc set up, it'll benifit GREATLY since the intake needs to be able to feed that blower. :)

Re: Tomsvx Intake for Dummies
 

This can only be speculation; who's to say to what degree the SVX's single resonator influences the intake?

Reading williaty's thread, he's proven that at low RPM, the MAF gets all sorts of confused without any resonators. Any bit of air that gets pulsed backward through the MAF causes a volume reading increase equal to that pulse, while the true volume is actually reduced by that amount.

The dyno readings of the TomMyx shown don't reflect the 1k-2k RPM range where williaty's readings show the MAF reporting substantially incorrect volumes.

It's not the difference of removing one being fewer than removing two. It's the difference between removing two out of three and removing all.

If only for the fact that I have no evidence to believe otherwise, I can't say that this is an issue with the SVX. The obvious similarities to the Impreza should lend to that there could be a comparable situation, though.

It would be interesting to see this tested before any hasty statements are made.

Re: Tomsvx Intake for Dummies
 

Thank you for that information, read all 3 pages.

Its unfortunate that we dont have dynos on a otherwise completely stock car, but in all reality it DOESNT matter.

I can see that its pretty much a no brainer purchase. It will improve the power of the car no matter WHAT direction you go (MT, S/C, Turbo, N/A, built motor or not) (provided a bit of exhaust work).

SO.... a secondary question... Why didnt subaru do this the first time?

You guys kick Subarus butt :lol:

Re: Tomsvx Intake for Dummies
 

production costs, assembly difficulty, etc. etc.

ask anyone who's installed one of these intakes how much "fun" it is to install :rolleyes: now, add this to a production line. now, add this to the time it takes to do any repair that requires the removal of it.

-Bill

Re: Tomsvx Intake for Dummies
 

simplicity. The stock intake works... it is that simple. It allows air to flow from a single pipe to dual inlets at the throttle body. People have tried to say in the past that the junction at the throttle bodies was a good way to increase the plenum's volume at WOT to create more low end tq. As we have seen in the dyno charts, the Tomyx keeps the same low and mid-range tq with the increases primarily in the upper RPMS.

I am sure that if Subaru was really trying to squeeze more power out of this engine it would be rated at 300BHP and it would have a better exhaust and a tuned intake. BUT they were looking for mid-range tq to conform with the low FD of the transmission to make it a good GT car, not a top end sports car.

I hope this helps.

Tom

Re: Tomsvx Intake for Dummies
 

http://www.sonic.net/~roo/FineLineSVX.jpg

Filter on the front side of the MAF sensor. Otherwise as stock as it came off the showroom floor.