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What is an I/C worth?


Guest bastaad525

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Guest bastaad525

What kind of power gain would be considered 'typical' from JUST installing an I/C alone? Assuming everything else stayed the same, same boost level and such, and the car was running 'right' not too lean afterwards or anything. Also assume the I/C is just about the 'right' size... big enough not to effect much of a pressure drop (and the boost turned up a little accordingly to compensate for any) and not so big as to create mad lag. I'm just looking for a ball park figure to expect from a good I/C... I mean we talking something small like 10hp or we talking much bigger gains?

 

I am 100% decided, no more avoiding it, installing my Buick GN I/C is the next big mod on my list (right after I install a relay for my fuel pump)... just wondering what to expect.

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the ic doesnt give you any horsepower at all. what it DOES do is allow your intake charge to become cooler in effect giving you less of a chance of pinging by keeping temperatures down and allowing you to safely run more boost.

 

that will give you more hp!

 

the ic is an integral part the a turbo system in the fact it helps keep things cooler. when the intake charge is cooler like i just said you can run more boost which gives you more hp.

 

did i just repeat myself :?

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Actually with an intercooler at the same psi you get much more horsepower because the air is significantly cooler and hence denser. You have probably felt the difference in a turbo car on a cool 40 vs 90 degree day. An intercooler can drop your intake temperature over 100 degrees.

On a 80 degree day using a intercooler with 70% efficiency along with a one psi drop of boost you will net a whopping 18% gain in HP (assuming charge temperture of 247F post turbo). BTW these are real numbers calculated for boost of 14-15 psi. the gains will be slighlty less for less boost (i.e. less heat) and increased for more efficient intercoolers

SO 18% gain with one psi less boost. then off course you can turn the boost up and let the real fun begin :D

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An intercooler DOES add power, if your fuel system and EFI can support it. I was running a high 14 with my stock turbo, 10 psi. I added my intercooler without changing the boost level (at the manifold), and ran 0.5 second faster with the same 60' time. I also gained 4-5 mph trap speed.

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Last back to back dyno comparison I saw before and after intercooler addition, same boost level: 1ft-lbs and 1hp gain maximum. (I believe on a 1.8L honda engine) regardless, the beauty is you can safely turn up the boost. Don't expect much just from the IC alone.

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Last back to back dyno comparison I saw before and after intercooler addition, same boost level: 1ft-lbs and 1hp gain maximum

Something had to be wrong with the set up. The 18% Hp gain I quoted earlier is from Hugh MacInnes the author of Turbochargers and it's based on accurate calculations. Other dyno runs have shown significant hp gain (~30hp, however I don't remember the details on the set up excpet that the only change was IC, then they turned up boost for another 40 hp gain). If you cool the air, which an intercooler does the air will be denser = more oxygen = more HP. It's not a subjective thing, it's fact. IC will have significant power boost at same psi. It does not matter what that one dyno reading with the honda showed, you will have much more than a few hp gained. And yes, pushing up boost and cooler engine are even more significant.

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Keep in mind you may not see much gain if you are regulating boost pressure at the compressor housing. The reason my setup netted me so much more power is the manifold pressure was the same before and after the IC install, not the pressure in the compressor housing. So I may have had the same boost in the manifold, it was much cooler (denser), so more air = more power.

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Guest bastaad525

Okay so something else is kinda confusing me...

 

Is ping directly the result of running too hot, too lean, both, or either or?

 

The reason I ask is... okay I thought primary cause was due to running too lean. Lean = too much oxygen to fuel ratio. Okay... so add an intercooler = colder, denser air = more oxygen = increased chance for ping? I know in the real world that adding an IC protects against detonation, but with that little formula I just typed out, it doesn't make sense why....

 

I guess as long as the fuel system can compensate for the increased oxygen, but then.. stock ZXT AFM maxes out at 4000rpm at WOT, so after that point, except for following a preset fuel ratio curve, how does the ECU compensate for more and more oxygen, up to the maximum potential of the fuel injectors? Even w/o the I/C, how does the factory ECU even compensate for increased boost at all past 4000rpm WOT?

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Okay so something else is kinda confusing me...

 

Is ping directly the result of running too hot' date=' too lean, both, or either or?

 

The reason I ask is... okay I thought primary cause was due to running too lean. Lean = too much oxygen to fuel ratio. Okay... so add an intercooler = colder, denser air = more oxygen = increased chance for ping? I know in the real world that adding an IC protects against detonation, but with that little formula I just typed out, it doesn't make sense why....

 

I guess as long as the fuel system can compensate for the increased oxygen, but then.. stock ZXT AFM maxes out at 4000rpm at WOT, so after that point, except for following a preset fuel ratio curve, how does the ECU compensate for more and more oxygen, up to the maximum potential of the fuel injectors? Even w/o the I/C, how does the factory ECU even compensate for increased boost at all past 4000rpm WOT?[/quote']

 

The answer is: either. If you don't cool your intake charge, and have the correct mixture, you may still predetonate. If you've maxxed out your fuel sytem (or your EFI), and you intercool it, giving it more air than the EFI can fuel, you can detonate from not having a rich enough mixture.

 

Who told you a factory EFI won't fuel above 4000 rpm? That sounds ridiculous. It's very simple how an EFI system with an AFM or MAF compensates for more air - it measures it. All factory systems have margin in them so they can perform beyond the original capabilities of the engine.

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Pinging or detonation is caused by running too hot. A lean fuel mixture is one way to cause the engine to run hot. Combine that with increased intake temps by not running an ic and you got a explosion waiting to happen. The excessive heat and pressure causes the air/fuel mixture to autoignite.

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Guest jjohart

Hi. I found the right local installer for my incoming NPR intercooler, plumbing and 3" inch exhaust..being that there is a shortage of aftermarket/turbo/qualified racing shops in eastern Massachusetts, I am expecting to take the car for 5 days of work at Custom Tubes in Woburn, MA. They were referred to me by N.E.Z club, with the caveat that they know a lot about the plumbing and hook ups, but not the "brains" of boost controllers and tuning. I said fine b/c this installer is much closer to my house if there's a problem, but then, I kinda p.o'd the company up in New Hampshire by telling them I'd bring the car up to them once the plumbing and basic system was there.

Actually, I haven't put it to them like that yet, but I am beginning to wonder if the primary installer is going to put me on a short road to ruin if I drive the car up to NH after his work, but before the HKS computer, Greddy Profec B and Bell Progressive Fuel Unit and whatever other fuel pump are in. Is there any danger in operating the car with just the I/C for a short period (2-4 days?)? Am I better off having the first installer hook up the hoses for the fuel computer/boost control, even if he doesn't know how to calibrate? Finally, can anyone point me to a post or link that explains how to make what I've heard is a "pop off valve", or a "cork", whatever it is has been said to be indespensible, but I don't see anyone selling it, so it is custom, right?

Thanks

John

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Guest bastaad525

Sleeper... you misunderstood me dude. I wasn't saying that the system can't fuel for over 4000, I was saying that, as I understood it, the flap of the AFM is moved as far 'open' as it can go, by the time you hit 4000rpm, at WOT. So after that point, assuming the engine is still accelerating, the AFM is not adding or changing any more info and is therefore having no effect on the fuel mixture other than saying to the ECU "That's all I can give captain!".

 

So what I"m trying to figure out, is after that point, 4000rpm, WOT, how does the ECU determine how much to increase the fuel relative to the air? I mean, the only other thing that it sees really changing at that point, is the RPM... and I guess the O2 sensor, though mine is disconnected. And in an N/A car or a turbo where the boost was left at stock, I assume that would be fine... just program in a set fuel curve above that point to match RPM and you'd probably be just about right. But when you start turning up the boost, and the computer isn't programmed for that nor does it really have any way to 'see' how much more air is getting into the engine, how does it compensate for it? Either in the case of just turning up the boost, and forcing more air and hence more oxygen into the intake, or when running colder temps, with an I/C or on a cold day or whatever, where the same amount of air just contains more oxygen... either way, how does the ECU know how to compensate?

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I'm not sure I did misunderstand you. All I was asking was, how do you know that's what the AFM does? I've heard it before from other people, but I don't always believe what I hear. That is a large part of the load/rpm curve that would be missing if the AFM were wide open at 4000 rpm. The reason I disbelieve it is the AFM is not sensitive to rpm, it responds to airflow. So it would max out way early on a boosted car, and I know they don't run bad at WOT.

 

But I don't have much experience with the stupid flapper POS, as I upgraded to a Z31 MAF before I started seriously tweeking the boost.

 

In short, you are correct, all the input the ECU would have is rpm in order to fuel above a certain airflow level, so once you hit it with more boost (or intercooled it), you would run more and more lean with increasing boost. If so, you'd want a RRFPR and a darn good fuel pump. But I wouldn't run one without a wideband and a long dyno session. :roll:

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Is there any danger in operating the car with just the I/C for a short period (2-4 days?)

You can run the car for as long as the chasis can hold the engine :wink: You do not need to make any adjustements whatsoever fot the IC. It's only after you turn the boost up over 11-13 psi that your stock ecu, injector.. might be inadequate.

 

can anyone point me to a post or link that explains how to make what I've heard is a "pop off valve", or a "cork", whatever it is has

at the end of your intake manifold (by the firewal) there is a large emergency relief or pop off valve (same thing). it's job is to release extra boost in case the turbo bypas valve or controller faile. So when the boost goes over8-9 psi, it vents the boost to the atmosphere. You can buy an adjustable one (safest way) or plug the one you have or weld it shut....

I bought an adjustable one from MSA many years back I don't know if they still sell them. Any way you don't need to worry about it until you turn the boost up over 8-9 psi.

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