Choice of Intercoolers?

[John Haggerty]

Brothers,

I've been watching e-bay and looking for an intercooler. If I go for one off a 6.0 L OEM, I'm hearing that it might have too much flow and add lag. My first thought is bigger is better. Is that true? What intercooler do you guys think would be best work for my truck? I'm thinking an intercooler requires some front end modifications no matter what. Is that true? Keep in mind I don't tow anymore and the truck is my daily ride. Also, I'd probably go Ken's pump, injectors and 3.54's (and new hard mounted Passport detector) at the same time.

Thanks,
John

 

[82fordtruck]

I know a lot of guys on here disagree with me, but here's my opinion:

A bigger intercooler is always better, within reason. It can't flow more than what's there now, so it will not flow too much...

The issue is a pressure drop. A big intercooler will have a pressure drop. I think this is acceptable. A turbo injects more air into the engine. Specifically, more oxygen is what the engine uses. As the air cools in the intercooler, it becomes less dense and contracts. There is no loss of oxygen, unless there's a leak. So, the lower boost, at a lower temp is preferable to hotter air at more pressure. You can also turn up a turbo to compensate for this.

I look forward to someone disagreeing with me here.... I'd like to debate the physics of this. Maybe I'm wrong?!?!

 

[F350camper]

I like the 6.0 IC. I think it would be a cool install. It is big though. You may want to see what would have to change between your grill and a/c condenser. I wouldnt worry about it being too big. I don't think you would be able to find a place to mount one that is too big.

 

[Freight_Train]

well,You actually want a pressure drop.The hot air on the inlet side of the IC will be thin and when it gets cooled it becomes more dense due to shrinking.This shrink causes the pressure to drop but you get a cooler more dense air charge.Which,if you hook the wastegate up to the outlet side of the IC then it will behave like there is less boost cause in reality there is less going into the engine.

 

[towcat]

I know a lot of guys on here disagree with me, but here's my opinion:

A bigger intercooler is always better, within reason. It can't flow more than what's there now, so it will not flow too much...

The issue is a pressure drop. A big intercooler will have a pressure drop. I think this is acceptable. A turbo injects more air into the engine. Specifically, more oxygen is what the engine uses. As the air cools in the intercooler, it becomes less dense and contracts. There is no loss of oxygen, unless there's a leak. So, the lower boost, at a lower temp is preferable to hotter air at more pressure. You can also turn up a turbo to compensate for this.

I look forward to someone disagreeing with me here.... I'd like to debate the physics of this. Maybe I'm wrong?!?!

keep in mind there is more than one dynamic at play here. Pressure drop is one thing, turbo lag is the larger issue when the IC is too large. larger IC is good for the heat soak, but there comes a point when the lag ceases to be annoying and becomes dangerous. If you are prepared and have tuned your vehicle for it, ie. a drag car, that is fine. controlling "explosive" Hp in a straight line is ok. But in the real world, that can be dangerous. I used to play around with Buick Gran nationals and the powerband with a large IC is a close example to dangerous. I knew when that sucker kicked in, and a few times I would stand on the throttle as I go into a corner and the power would kick in midway. next thing you would see is a car frying the tires and powering through the remainder of the corner sideways. I've learned by trial and error over the years with turbos and IC's that you need to find a balance between boost, pressure drop and turbo lag. A turbo that is overboosting is inefficient, too large of a pressure drop defeats the purpose of a turbo and turbo lag will leave you napping at the lights or spinning out of control. Oh yea, I sold my GN in one piece, with no battle damage

 

[82fordtruck]

Towcat -

I had not considered that, but I think that could be addressed with making sure that the tanks at the end are not too big. Your concern is one of volume, correct?

I wouldn't think those are too much larger in volume, they would have to flow a similar amount, only at a higher pressure

 

[h2odrx]

keep in mind there is more than one dynamic at play here. Pressure drop is one thing, turbo lag is the larger issue when the IC is too large. larger IC is good for the heat soak, but there comes a point when the lag ceases to be annoying and becomes dangerous. If you are prepared and have tuned your vehicle for it, ie. a drag car, that is fine. controlling "explosive" Hp in a straight line is ok. But in the real world, that can be dangerous. I used to play around with Buick Gran nationals and the powerband with a large IC is a close example to dangerous. I knew when that sucker kicked in, and a few times I would stand on the throttle as I go into a corner and the power would kick in midway. next thing you would see is a car frying the tires and powering through the remainder of the corner sideways. I've learned by trial and error over the years with turbos and IC's that you need to find a balance between boost, pressure drop and turbo lag. A turbo that is overboosting is inefficient, too large of a pressure drop defeats the purpose of a turbo and turbo lag will leave you napping at the lights or spinning out of control. Oh yea, I sold my GN in one piece, with no battle damage

WOW
i'm glad i don't have a turbo?

 

[towcat]

Towcat -

I had not considered that, but I think that could be addressed with making sure that the tanks at the end are not too big. Your concern is one of volume, correct?

I wouldn't think those are too much larger in volume, they would have to flow a similar amount, only at a higher pressure

Volume is the biggest part. but keep in mind that you can't choke down the airflow to compensate. let's say yo have a IC with a large heat sink area and small tanks. you can keep the pressure up at the tank level by controlling the size, but how will you handle the pressure drop from the increased core area as the air hits the IC core? I guess a good analogy would be like a river you go whitewater rafting in. In areas, the water is moving very fast and other areas where it pools. the pooling area can handle a larger volume of water, where it takes more time to fill therefore it is slower.
Realistically, we have two practical choices. On one end, there is the factory 7.3 and 6.0 IC. They are a full height IC and prolly the largest we can physically fit onto the front of the truck. The other end of the extreme is the IC's sold by Hypermax and ATS. They are the "half height" IC's. the full height IC's are prolly the best you can get for colloing the air charge. the half height ones are at the minumum for the job without too much compromise.
here's what I found on my truck. The half height does a pretty good job and I have no complaints. Also, the half height does not signifgantly block the AC condensor but will impair the cooling capacity of the AC. I am running R134 freon and not by choice either. R134 needs higher pressures to work right and on a hot day, that pressure hits the vent valve on the AC compressor very easily. So....that's you food for thought for today.

 

[towcat]

WOW
i'm glad i don't have a turbo?

keep in mind my example is using a "hot rodded" gasser. Diesels are alot more sedate.