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Discussion Starter #1
a recent technical paper from OE supplier Behr on charge air cooling technology indicates that keeping internal air volumes small for the sake of throttle response is an important consideration when designing CAC systems for OE applications --- Eric

True, but first that states for OE applications, which of course any tuned car would not fall under.

Second, this is a quote from www.thedodgegarage.com:

Myth # 17 Big intercoolers cause lag

Answer- False!

I'm guilty of this one, you would think the extra mass of air and the long hose runs would cause lag no? Well it doesn't, as a matter of fact in the K-car after I installed my double size intercooler the throttle response and spool up was NOTICEABLY better.

Now not to offend the folks at Behr, but they ARE trying to sell you an intercooler. Presumably if they can get you to pay more for a cheaper to make, smaller one, they would make more money, no? I do agree though, that unnecessary piping is well ... unnecessary.

But a larger intercooler really won't hurt anything but your wallet at worst, and in the very warm weather we have here in California I think it's not at all bad idea. I'm not just talking about better flow, but more cooling surface area.

For some physics, while air velocity and density should be taken into account, one would assume that in a very large intercooler at low rpm the air mass is travelling rather slowly. Giving it much more time to cool. In a smaller intercooler it has to travel through it more quickly and has less time in contact with the metal surface to cool. At high rpm not only does the air go slower, but its initial temperature is lower because the turbocharger doesn't have to work as hard to compress the air, which also takes load off the turbo and helps give it a longer life.

As for turbo lag ... it's really not that big of an issue. Perhaps 99% of the Saaber's out there like instant turbo response, but honestly I'm willing to wait for a second. If I'm in THAT big of a hurry I'm going to pop it down a gear anyway, and believe me at 4500 rpm you won't notice any turbo lag even with the largest thing of an intercooler you can fit in the front of your Saab.

However, if one does not want to spend the big $ on a larger intercooler, and one is also satisfied with the flow of the existing one ... water injection will take the average 70% efficient intercooler and get it to about 90%. This means that while perhaps you'll be missing out on a few hp as a result of some backpressure before the intercooler, you won't be worrying too much about heat soak. A home made water injection system can be fabricated for a fraction the cost of an intercooler upgrade. So it might be the best possible solution. Nevertheless, if I had the dosh to spend, one of my first upgrades would be an intercooler ...

Cheers,
Dubbya

edit: Here's some interesting reading from the Dodge Garage: http://www.thedodgegarage.com/turbo_myths.html

And of course ...

http://www.thedodgegarage.com/turbo_intercooling.html

To be fair the stock intercooler does start do have a fair amount of pressure differential between the inlet and outlet once the boost starts going up. I'm told less then a pound or two is ideal and at 15 psi the stock one is about 2 psi, however... -- G. Donovan

That was on a 350 CFM intercooler ...

Very good reading indeed, from someone with a great deal of performance 4 cyllinder experience.
 

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Sorry Dubya, but I know that website quite well, and, frankly, compared to the wealth of info here and at other Saab sites, its contents are hardly to be qualified as very scientific. In fact, some of the statements there made me laugh. Most of them are somewhat correct but hugely oversimplified, others are plain misguided. Look at the injector stuff there. All sounds rather crude to me, no?
Anyways - there's no clarification on that site whatsoever for the statement you quote. Without that, it's just one of a few thousand places of potential misinformation on the web. Even if they display the word 'WRONG!' in big shiny capitals on their pages does not lend it any more credibility. The most qualified statement about bigger IC's and turbo lag I've yet heard is along the lines of 'I haven't noticed any...'. Hm.
And, unlike the tuner sites, Behr is not trying to sell me an intercooler. I hardly qualify as an OE manufacturer, do I? Every now and then, a major Tier 1 supplier is so nice to me as a technical editor (and my collegues of other media) to lend me a (virtual) peek in their R & D centers to see their latest developments and hear about how they see the future. That's called PR.

Afte all is said and done, it's quite simple. What applies to forced induction systems, does so all across the board. It's not that there's two laws of physics, one for OE manufacturers and one for tuners. In fact, the highest goal you can achieve is to make something an OE manufacturer would have built if it weren't for the fact that the OE did not see a lucrative enough market for say, an M/RS/Type-R/etc. competitor from Saab. It's easy to improve one poart of a car, but it's very, very hard to make the car work better as a whole, and something most aftermarket, let alone 'hobby' tuners fail miserably in IMO.

Bigger is not better.

The bigger your air volume between turbo and intake, the more time it takes to pressurize

The more restricted the path between turbo and intake, the more time it takes to pressurize

Balancing the two against each other AND the cooling efficiency, that's the whole story.

A truck intercooler placed three foot in front of your front axle line might only weigh 15 lbs - it's 15 lbs placed at the most awkward spot there is, and has a disproportionate effect on the car's weight balance. BMW would not have bothered with replacing the roof with a carbon one on their M3 CSL for six lousy kilograms if it weren't from the fact that it were six kilograms as far from the car's center of gravity as the car would extend in a vertical plane.

But I disgress. Back to my point:

A Trionic-controlled Saab can be persuaded to give sh*dloads of power with better-than-stock driveability and full reliability with new Trionic software and a 3" downpipe. This will give as much power as your turbo's airflow capability allows with the OE intercooler or in the NG900/early 9-3's case, a modest upgrade.

A software upgrade is a software upgrade from a price point of view, be it Stage One, Two or Twenty-Three. Only the associated hardware varies.

Any gains coming from a 'serious' intercooler upgrade at this modest tuning stage pale into insignificance with what the Map-Tun, SQR, Speedparts Stage 2-3 upgrades achieve by themselves.

At the point you need the big IC, your turbo has long reached the ragged edge of the compressor efficiency map.

At the point you upgraded the turbo, you are already at the ragged edge of your Saab's handling capabilities.

So, here I am, with a car that's already FQ (F... eh, airly quick ), say, a 900/9-3 like Maarten's or Eric's, and another thousand dollars or so burning in my pocket.

What should I do? Order a custom IC from Bell or Spearco and spend countess hours on making it fit (probably mutilating the rad support and stuff with a hacksaw in the process - who cares about crash performance? )to make it 'theoretically' right and gain another couple of horsepower on top of the 270 or so I already have? Will I even notice the difference? Am I inclined to take it that much further that I would know the difference? Ask Maarten what that 390 bhp 9-3 is like on the road - from what I gather it's not something he's too keen on aspiring to (even the owner says the car was probably at it's best and most balanced at 260 hp - seems it's hard to resist overkill ).
Naah - I'd concentrate on making the thing stop and/or handle - I mean, the general consensus is that even in it's stock 185 bhp state of tune the 900/9-3 could do with some help in the latter department...

Balance is the key. I've seen/heard about so many folks swapping components that are perfectly adequate for the job with very expensive ones because they're 'better' without seeing the big picture. I've also seen folks getting about as much power as you want to have on a FWD car with mostly stock hardware (what about 220ish wheel horsepower on a c900 with stock turbo and intercooler?), just because they've identified the weakl inks in the system and developed the simplest workarounds you can imagine, and their ignition timing and fueling strategy is so much more competent than that of people who just throw around money. I read about rich kids spending tens of thousands of dollars on a c900 engine, shooting for a 500-550 hp goal. I ask, what are you gonna do with that kind of power in a c900? I want to pick on Vipers and 911 Turbo's, th kid says. Ain't gonna happen! Even if he eventually gets 500 hp or more - it'll be undriveable with all that power and just the front wheels to transfer it to the tarmac. There's not enough space for wheels and tyres that are wide enough, and if you manage to fit them, the car will handle like a lead brick. It will need race or drag slicks to get a 0-60 of under 5.5 seconds - something you would have achieved with half the power and a quarter the money. Yeah, he's got a ball bearing Garrett turbo and a billet crank and rods and a huge Spearco IC and fuel pumps that support 1,300 hp - Vipers and Porsches and Mark A's RS2 and possibly Eric's wife's Twingo if Eric drives it, will run rings around him and fall over themselves laughing. None of those has billet cranks and fuel pumps good for 1,300 hp. They were built with components adequate for the job on hand, within the limitations of the overall car. They have enough leeway in them to maintain reliability where it matters. They seem to be 'built down to a price' in other respects. But swapping those parts for 'better' ones does not always make a better car.
Myself, I am inclined to look at standard cars that are in the performance bracket I can realistically aspire to starting with a Saab (say, the Mitsubaru Turbonutter Spec ZZ level) to get a feel for what's needed to get at that level with maintained reliability, rather than at the bling bling world of aftermarket tuners. I don't see any Spearco intercoolers in there or GT40 ball bearing turbo's in there. I see generally stronger bottom ends with oil cooling jets, I see properly sized (but no more) turbo's, I see lots of work on the handling and braking front, I see some bodyshell strenghtening, I see lightened parts and semi-racing compound rubber...
 

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Originally posted by MarkA:
[qb](p.s. I see a new clutch on my RS2's future     ) [/qb][/b]
Whoops... nothing to do with 'The Fåst ånd the Furiöus 3: No Sleep Till Venlo', I suppose?

Hopefully it won't be that expensive a job?
 

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I difinitely agree with the overall balance equation. My car at 260 hp, seems to have a good balance between power, handling and braking abilities.

I also have to agree on the idea that a smaller intercooler and pipe setup will pressurize more quickly and therefore display less lag. Physics can't be denied. I also have to add that Hirsch's opinion for me is a thicker intercooler will the best, next upgrade for me. Theirs, of course, or the other bolt in units that are simply thicker will cool better and give better performance on the street, although, not necessarily on the dyno.

I also have to agree that drivablity is just as important to my car as ultimate power. I have no desire to deal with lag in a street driven car. While someone with their huge I/C and oversized turbocharger are waiting for the boost to set in, I'll have a big lead that will be hard to make up, especially on tighter roads. I also won't have to plan 3 seconds ahead to make a quick pass on a twisty road.

So I guess, I should just be saying, I totally agree with you on the one, EvS! Great post!
 

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nothing to do with 'The Fåst ånd the Furiöus 3: No Sleep Till Venlo'[/b]
He he .. actually the clutch is fine.. it's just that I can see a future, if I keep doing 6700 rpm 4wd launches at traffic lights, which involves a new sachs comp clutch...
 

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I have read in utter amazement and total agreement that what Eric has written for at least 5 times. Many of the things he points out are so much along the lines of what I have always believed myself. But in order NOT to trample on people's long toes, I normally just agree with many questionable points, even when I believe otherwise . As an example I just have to raise the subject of what I had done to my car. Even SAAB aficionados who first poured under my bonnet, still refused to accept what I was claiming. From there my reluctance to ever post pictures of what is under my 9-3 bonnet. Sunday's Tring meeting was a case in point. The proof of the pudding eventually laid in the tasting, ahem, driving...
Examples where I have disagreed with others, so called facts on some professional sites etc., and did things my own way performance wise:

ECU - I refused to accept what was on offer from Abbott, Speedparts, Hirsh etc. So I designed my own graph and then paid to get it programmed accordingly. Who else has done the same here? When I stated on more than one occasion that I had the turbo spool up time reduced to around 1500 RPM, how many people creased up laughing? Result? Just ask BillJ if he agrees with me.

 Balance is the key. I've seen/heard about so many folks swapping components that are perfectly adequate for the job with very expensive ones because they're 'better' without seeing the big picture.  [/b]
Very good observation. Over the years I have seen people asking for advise on uprating their Viggen brakes. Why? I got a friend with brakes and rotors know-how to use those same Viggen parts to give me stopping power I can count on. Anyone wants to dismiss that as impossible? Too many people believe that throwing money at "better and more expensive" parts WILL solve the problem. WRONG!!!

Quote Adrian:
As for turbo lag ... it's really not that big of an issue. Perhaps 99% of the Saaber's out there like instant turbo response, but honestly I'm willing to wait for a second.  [/b]
I remember a topic on the TD04 turbo lag. I am still sctratching my head on this. My TD04 will kill you with power long before you have reached the middle of the accelerator pedal travel. Don't believe me?

T5, T7, red versus black DIC. Which combination is best? And which one would you ONLY consider, or expect to see, on a B235R block? Well I got a T5 and red DIC on a B235R. So much for what other experts have been preaching on various SAAB boards. What I believed would work best for me, proofed me right. Had I listened to others too much, I would have never agreed to carry out the mods I did, including dropping a B235R block under the bonnet, and then butchering the whole SAAB Trionic and DIC setup!

I have no cone filter, Forge BPV, 3" downpipe etc. Do I need them? Not that I can find any reason why I should. I fitted the Abbott steering clamp, but rejected the rest of the VRK as a waste of money. But others swear by the VRK. Dunno. Nobody has yet lost control in my car due to torque steer, eventhough I would whip the pants off any standard Viggen, and then some.
That the 9-3 as a whole needs a better suspension
setup is the only thing I can say I can agree on. But look at the buckets of dosh that needs throwing at that problem .
 

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Actually .. as someone who has a car with 'big' injectors, massive intercooler, and a mother of a KKK turbo.. I can say that lag is for sure a [expletive deleted]..

I've got to drop a gear unless I'm sitting on 4000rpm if I want to see instant pick up... mind you it helps that mine revs 7400rpm... at least when I'm rolling it never goes off boost...

Drivability and balance are key.
 

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Quote MarkA:
 I've got to drop a gear unless I'm sitting on 4000rpm if I want to see instant pick up... mind you it helps that mine revs 7400rpm... at least when I'm rolling it never goes off boost...  [/b]
In your opinion, is that a general rule with that kind of turbo, or just plain incompetence on the part of the AUDI engineers in being able to "do better" ECU programming wise?
 

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 I would have never agreed to carry out the mods I did, including dropping a B235R block under the bonnet, and then butchering the whole SAAB Trionic and DIC setup!  [/b]
Sorry mate.. but I thought you said it was from the factory like that?
 

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In your opinion, is that a general rule with that kind of turbo, or just plain incompetence on the part of the AUDI engineers in being able to "do better" ECU programming wise?[/b]
Actually the car is built and designed by Porsche for Audi...it develops 315HP and 410NM of torque in standard stock tune and propels the estate from 0-100kph in 4.8secs and on to a top speed circa 170mph.

If I want to start ECU programming I'm looking at 360HP and 480NM before I have to change ANY hardware (including the intercooler).

The car is way within the safety zone and is fully homoligated and TuV approved and meets and exceeds green laws... much less than can be said of any 'tuned' car... i.e. properly reliability tested.

Given that the car is only a humble 2.2litre 5cyl , I'm sure you'll agree that it's not a bad piece of engineering on behalf of the Porsche developers.
 

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Quote MarkA:
 Sorry mate.. but I thought you said it was from the factory like that?  [/b]
Would YOU have believed me if I had said then that I had chosen that route all by myself, with no previous street cred on SAAB mods? I guess not... As I pointed out above, sometimes I have had to go along with the flow, just to avoid trampling on the toes and knowledge of others. I admire Eric in that respect for not bothering about those kinda niceties.
 

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Would YOU have believed me if I had said then that I had chosen that route all by myself, with no previous street cred on SAAB mods? I guess not... As I pointed out above, sometimes I have had to go along with the flow, just to avoid trampling on the toes and knowledge of others. I admire Eric in that respect for not bothering about those kinda niceties.[/b]
I'd have believed you!.. it's more credible to think that, than if it were some strange preproduction saab viggen as previously asserted.

At any rate .. it's your car.. you are entitled to do with it what you want.
 

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 I'd have believed you!.. it's more credible to think that, than if it were some strange preproduction saab viggen as previously asserted.  [/b]
In that case I publicly apologise to you and all other SAABSCENE members for having hidden the true facts behind the mods.
 

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Discussion Starter #17
I want to pick on Vipers and 911 Turbo's, th kid says. Ain't gonna happen! --- EVS

Scroll down to the date 8/19/03 on this page.

Here's the quote I'm referring to, On the autocross side of the table Barry Miles showed off his mad driving skills in the Hooters Omni by blowing away a field full of Vipers and winning the event with a 3 second lead!! Several other FWD Dodges also did extremely well in this event much to the annoyance of several Viper owners who had trouble keeping up.

So these very unsophisticated guys are blowing away Vipers in turbo, front wheel drive, four cyllinder 1980's econoboxes. I know you hate that site. But those guys really do pull off some incredible stuff. I mean honestly ...

Scientific? No. But pragmatism at its best, and of course ... it works. btw One of the Omni's runs an 11.8 in the quarter mile, which would easily pick on any stock Viper, and most stock Ferraris including the 360 Modena which runs in the mid 12's.

Cheers,
Dubbya
 

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Originally posted by StanleyB:
[qb]
In that case I publicly apologise to you and all other SAABSCENE members for having hidden the true facts behind the mods. [/qb]
Nevermind about that, StanleyB, you just let me drive it yesterday - you didn't tell me the half of it
I think, like MarkA, we're all going to be somewhat more interested in this special 9-3 ...but perhaps it needs a new topic?
 

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One of the Omni's runs an 11.8 in the quarter mile, which would easily pick on any stock Viper, and most stock Ferraris including the 360 Modena which runs in the mid 12's.  [/b]
I think you prove Eric vS's point. My comment about the above is yes in a straight line... until he hits a curve.. and then the viper/ferrari/porsche 911 Turbo annihilates it. Guy won't see which way the exotic went. Why ? cos the manufacturer spent as much time in development of a balanced car that didn't need NOS, can run on street fuel, at any altitude, that can tool along at 180mph ALL DAY on a 'bahn, that can handle, brake and change direction properly.

Balance!
 

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Discussion Starter #20
lol Mark A ... the first part of that quote is from an Autocross event, where the Omni blew away the field of Vipers on the straights and through the corners. Sorry if I didn't make that clear.

yours,
Dubbya

edit: Also ... I suggested a larger intercooler because irrespective of lag it makes more power (if it's properly setup, some large could make less if setup wrong). My driving style is quick accellerating and slow through corners. That's just how I drive on a daily basis (not at a track event obviously, but I rarely go to those), and I'd make more use of a few extra horeses far more often than I would a much rougher sportier and lower suspension. The ride is harsh enough as it is.
You can argue ballance till you're green in the face, but I only suggested the IC because it makes more horeses in a straight line than suspension.
 
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