dumb intercooler question

For the type of driving you do, and the mileage of your car, save your money to buy a 3.29 trans.

Sir Psycho Sexy wrote:

For the type of driving you do, and the mileage of your car, save your money to buy a 3.29 trans.

Grocery gettin, work commutin Buick. with just a lil bit of a need for speed

I would like to get hood cowl to accommodate a gen V sittin on a full size IC sittin on a 1" phenolic spacer.. but....

she really needs paint and i know the trans is the weak point right now. If IC will give me 30+WHP then i may consider a 10% increase in power but if it's any less than that, I dont think itd be worth the dough right now. But how would I know until I do it and test/dyno? I feel like this whole 3800 game is a big experiment. The truth may be out there but I can't find it

Intercooling lets you run higher boost and/or increase timing, that's it. There's no power gain unless you tune spark or drop pulley size. E85 gets you the same thing; it's a kind of a liquid intercooler.

If you've reached the desirable timing curve for WOT (there is a limit) running E85, and you're running within the M90's boost efficiency range (also limited), intercooling may be a waste.

Focus on breathing mods.

AA wrote:

Intercooling lets you run higher boost and/or increase timing, that's it. There's no power gain unless you tune spark or drop pulley size. E85 gets you the same thing; it's a kind of a liquid intercooler.

If you've reached the desirable timing curve for WOT (there is a limit) running E85, and you're running within the M90's boost efficiency range (also limited), intercooling may be a waste.

Focus on breathing mods.

AA, this is what I was thinking. If I can max out with a 2.55" pulley with 0 KR than what more can an IC possibly do?

Some people disagree with this and say an IC will still add to torque #s and make gainz. Where is the ncbi equivalent of a 3800 science reports when you need it?

You know, those people could be right, technically. When the IC cools the air, it becomes denser, but this happens after the MAF sensor, so the PCM wouldn't know to add more fuel. If you tuned your fueling table to reflect the extra density from the temperature drop, maybe some extra power could be had.

I meant the primary purpose of IC is knock reduction, not power gains. I shouldn't have said "no power gain", but for the money it's a terrible investment for that purpose. On the other hand, every bit helps. I've never run an IC, so maybe it is more than a little bit.

AA wrote:

I meant the primary purpose of IC is knock reduction, not power gains. I shouldn't have said "no power gain", but for the money it's a terrible investment for that purpose. On the other hand, every bit helps.

Whaaat?


The air leaving the blower under boost (assuming more than stock) is usually over 150F higher than ambient intake air. Extra flow through the motor only has a minor impact on that heat, dollar for dollar. When you go into boost on a cool day, the air entering the intake would sear your skin.
If the concern is that it'd be redundant to intercool because you're running on e85, remember how hot things are in the combustion chamber. You can't really overdue it on cooling efforts there. If you weren't running an xp cam now, I'd be suggesting to get a cam, but having already improved flow through the motor quite a bit with that, I'd be looking at intercooling at this point before getting heads. Don't forget also that cooler air means denser air, which translates into higher VE just like more flow through the motor does except, like AA said, it's invisible to the maf sensor so that's where AFR tuning comes in.

I dare say I don't even like to consider an IC a kr control mod necessarily. It's affective at that because often people are already running a smaller pulley and pushing things before they get an IC. Tuning being unchanged from before to after, the AFR would be much richer before the ic (because you have more air with the pulley but it's hotter air so the affect of the smaller pulley is reduced a bit) so if you have kr at that point and it's already rich because of the overstated maf due to the lower air density, you're just in bad shape to begin with and the newly installed IC fixes it because it not only pulls out the heat but also puts the perceived air (by the maf) back on track so actual afr is better and you get a huge bump in power.
The premise of all that is that the tune & hardware of the 3800 isn't so great for resolving true air density at WOT. It's completely dumb to how hot the air charge is after it passes the IAT. It's fine while in closed loop because it'll just look at o2 and trim against the result AFR (plus you're not pumping out all that heat right then) but open loop (every time you get on it), you can get into trouble if your result air charge temp is a lot higher or lower than what the tune anticipates at WOT.

Yeah, I see your points. There are different basic approaches to building power on these engines. Intercooling supports the idea of "I can boost more because KR is eliminated" more so than "cooler, denser air allows more fuel to be added", IMO. Knock reduction is the main advantage, even though there are some obvious gains from cooling, like the bump you get driving on a crisp, fall day vs. hot summer.

E85 does the same but different - it allows more fuel to be added because it's A/F ratio is higher proportion of fuel, and it the alcohol cools combustion temps, so can boost more and fuel more. So I get the idea - more fuel equals more torque for a given amount of air crammed in.

But looking big-picture, it's "better" (my opinion) to flow more AIR through the engine, using less boost. More fuel gets added, M90 is happier, and MAF increases = HP. That's what heads will do for you, and with E85 you could get by without IC and still have room to improve with exhaust mods.

Imo, dollar-for-dollar, heads alone > intercooler alone for making HP. And the way you are making that power (with better breathing) should be more durable due to its simplicity. With heads, the engine is working like an more efficient pump; with IC it's more like regulating an overflowing dam of air. Not saying "big boost" is bad for everyone, but every breathing mod I did to my engine made me want to breath more boost less. Also pushes the torque band to higher RPM, for more usable power, but that's another chapter.

How much weight do you think an intercooler set up adds? radiator, coolant tank, hoses n stuff? ~40lbs?

Awwright gents... I've read the arguments for and against intercooling in this thread, but one thing you haven't addressed is intake air temp.

If you are able to cool the intake charge before it hits the MAF and relocate the ACT sensor, why not gain air density before the supercharger ever sees it?

In theory, cooler air in to the blower results in a more densley packed charge, and if the cooling happens before the ACT and MAF, the PCM responds accordingly.

My solution is a small R134a coil (run off of Buick's OVERKILL climate control system) in the intake duct hose.

It would take very little modification to the HVAC system and only about 4oz more refrigerant to fabricate the part into the air duct through the muffler opening and a modified manifold with two small switches/servos on the a/c lines.

My logic is for those of us in the Southwest who drive to Vegas in the summer (ambient air temp can be over 120 degrees on a regular basis).

Thoughts on an R134a pre-cooler?

manic
(36 year pro, 25 years ASE certified...RETIRED)

The supercharger itself heats the air. Anytime you compress air, it's temperature goes up. Cooling it before the supercharger would have a minimal effect I think.

LARRY70GS wrote:

The supercharger itself heats the air.  Anytime you compress air, it's temperature goes up.  Cooling it before the supercharger would have a minimal effect I think.  

Maybe cool the air before & after instead of just before? Those would be two small evaporators.