Good talk Rich! / resonatorectomy

Found the talk you gave really good and well set out, look forward to the next.[]

One thing that got me thinking was when you said a small turbo running say 1bar of boost wouldnt produce the power that a bigger turbo would produce running the same boost. Why is this? Surely its forcing the same amount of air into the cylinders isnt it? Or is it down to the temperature of the air forced, ie it would be hotter in the smaller turbo?

Oh yeah and what was the smaller/thicker book called you had with you?

Cheers, John

 

Thanks, glad you enjoyed it.[:I]

Tried to get as much info in as possible without making everyone fall asleep.[|)] I think if you talk for any longer than 15 mins, people start to lose interest.

The reason a bigger turbo will produce more power at the same boost as a smaller turbo is that it is flowing more air.

Think of it this way (this is the best way I can think of describing it), imagine you have a car tyre and a truck tyre. To get 30 psi in a truck tyre you have to put a lot more air in than you do in a car tyre to get the same pressure, as the space inside the tyre has a bigger volume. More air has gone in but the pressure is the same.

Same with turbos, because the compressor housing is bigger, at the same boost pressure it is actually flowing more cfms (cubic feet per minute) of air, so there is potential for more power.

You are also right in theory that a TD04 at 1.2 bar would be putting probably more heat into the inlet charge than a TD05 at the same boost as it would have to be "working harder".

The booked was called "Forced Induction Performance Tuning" by A. Graham Bell. Its a really good book with lots of Subaru specific info too.

Cheers
Rich

 

Good explanation, once again!

No chance of falling asleep, i personally find it very interesting and have spent many a friday night in the pub (call me sad) talking about this sort of stuff, trouble with that is i tend to forget what we were talking about and what conclusions we came to!! [xx(]

Cheers, John

 

Hi rich, your talk must have been good coz my wife was kept interested by what you said and she hates car stuff so well done[]

Just a quick question for you!
Would having a bigger turbo than the TD05 stop "Detting" or would you also need a better intercooler as well or am i barking up the wrong tree here? Or if you had a bigger turbo and you ran more boost would it still be the same[?]

Sorry, thats 2 questions[]

 

Kev, by having a bigger turbo i suppose that the charge temps for the same boost would be lower and help prevent det but you would suffer from more lag as the turbo being bigger would take longer to spool up. Having a better intercooler wether it be a top mount or front mount would be a better way of reducing charge temps and help prevent det.
Also if you add ducting to your induction kit to get as much cold air to it as you can would also lower charge temps.

Then of course there are remaps (TEKs) or replacement ECUs (Link for eg) that when mapped properly should stop det occuring at all unless you put dodgy fuel in or add more mods without getting the map tweaked.

Not sure what you mean in question 2, but if you ran more boost you would generate more heat so det would be a problem unless you cool the air via a better IC (if your current IC couldnt cool the air enough) and add the correct amount of fuel to suit if your injectors allow it.
Hope this helps somewhat, im sure Rich will correct or add where neccessary! []

XXX

 

Triple X,

Thats pretty much what I would have said. Good explanantion. []

Heat management is absolutely essential in the quest for power.

If you have an induction kit, you should try as much as possible to keep underbonnet temps as low as possible, get as much cold air into the filter as possible. Whatever size the turbo is, it will put a considerable amount of heat into the inlet charge, so intercooling is fundamental. The bigger the intercooler, the better and the more air you can get to flow through that intercooler, the better too. Thats why the bigger bonnet scoops are a good idea. A bigger intercooler will also allow you to run more boost more safely. Thats why the 93-96 cars are at such a disadvantage as they have a tiny intercooler and a tiny scoop to get air in, but good news, MRT are working on a bigger one for the 93-96 models.

Also wrap anything that gives off heat, to keep the underbonnet temps down. So you should wrap the downpipe, the turbo too if you haven got a heatshield on it. Also, you could insulate the water hoses too near the induction. Every degree helps.

Think "cold air" all the time and you won go far wrong. Thats why I have the bonnet scoops for my induction and Ive taken out my inner twin headlight, to get as much cold air into the intake as possible.

Glad your missus found the talk interesting, Kev, thanks.[]

 

Rich,
Whats the best way to go with the original air box ?

For Example - Is it a good idea to flow cold air in from vents / ducting to remove heat build up or will this create problems with the existing air flow charataristics.

 

Difficult to say beyond fitting a decent panel filter.

You can provide an additional cold air feed or feeds to it by drilling a large diameter hole/holes (BELOW the filter of course)and piping in cold air via ducting from the front of the car. Ive seen this done on and S2000 Honda to good effect. However, the S2000 has a HUGE airbox, so the OEM single feed is the weakest link. The subaru airbox is not as big, so additional cold air feeds might be pointless if the rest of the inlet system is the restrictive part. A chain is only as strong as its weakest link.

Some people opt to putting lots of drill holes the base of their airbox out, to drag more air in. We used to do this as kids on our Escorts and Fiestas. This is a crap idea though, because in no time you drag gunge into your airbox which clogs up your filter and makes it less efficient. If you are using additional cold air feeds into the airbox, they should really be filtered in some way, to stop large debris from getting into your airbox.

As long as your MAF is registering the incoming air it shouldn be a problem, it will fuel accordingly, so adding cold air feeds should have no negative effects.

My preference, particularly on cars before 01 is for an induction kit to be honest over the standard airbox. 99-00 cars have to be more cautious due to MAF weaknesses, granted, but having said that we have several customers with induction kitted 99-00 cars that have not had problems with MAFs, but yet others that have. We have also had many 99-00 customers with standard airboxes that have blown MAFs, so it seems more to be "luck of the draw" than "induction kit or airbox".

 

Cheers. []

 

Chris, for info I have run a Blitz LM Induction kit for a year or so without any problems. Just remember that they can pick up underbonnet air which may be warmer. <<i>treads carefully cos this is a much debated issue</i>[]>

Possible best combination is something like the APS arrangement where the filter is placed in the wing void and piped to the housing containing the maf.

 

If you want to keep the standard airbox, why not have a resonatorectomy? []

MRT have doen dyno tests in Aus and doing this can free up up to 2.6hp at the wheels apparently, which would mean about 5 at the flywheel. Small, I know but its hp for FREE! Just put some gauze or mesh over the airbox intake to stop leaves and other large particles being sucked in.

 

Cheers Rich,
Andrew C mentioned that idea to me a while back, but Ive never got around to ripping the inner wing apart.
Might just prompt me to get a move on as 5hp for nothing is my ideal sort of mod ( no doubt barracking will follow shortly from Trev, Tripple and Mr Mccord re owt 4 nowt [] ).

Whats the best method for removal ?
Cheers
Chris

 

Chris, the procedure for a resonatorectomy is detail in the book WRX Training. The first and best book I have read about modifying Scoobs. It also includes detailed comparisons about the underbonnet temperature airbox vs ram air issue.

At £30.00 (from Jap) its the best mod Ive done, seriously recommended.

Put into your terms, it could EASILY SAVE YOU £30.00 of useless mods![][]

 

£30?! [:0]

Steve, for the sake of "Owt for Nowt" Towers can you not scan every page and post a link to them? LOL []

 

<lol at TripleX>

At £30 its less than 1/2 the cost of a blown maf if you get it wrong and together with other tips and tricks is the best £1/hp ive spent![]

 

Libary here I come [][]

 

Whats a MAF?

 

MAF = Money and Finance ?
Talk to Morgan Stanley, apparently they have an expert on LINKing MAFS []

 

30 Quid from Towers for a book!!!!

Please all bear in mind, this is the guy who offered me £50 for my interior and would then sell his on for £200.

He is even charging me rental for borrowing a wheelbarrow off him.[]