Intercoolers for dummys

[f-two-fiddy]

its been mentioned several times that adding an intercooler wil add lag. my boost gauge moves slightly slower at first but then takes off quickly. the power comes on quicker now even when the gauge moves slower. You have to remember that the inceased vol of air going into the motor is also going out and through the turbine housing. I used 3inch tubing and a 6.0 cooler and did not FEEL any increase in turbo lag.

Lag is the turbo trying to fill the intake track, now larger, as quickly as it can.

A smaller and more effcient IC will not add lag. If You research some of the better manufacturers, some state .2 PSI pressure drop across their units.

I've read of PSD IC's loosing 3-4 PSI. @ 7 lbs thats 50% pressure loss.
If You have to monkey with the wastegate, You've lost pressure. Trying to up the boost by keeping the wastegate closed longer is heating the intake charge even more.

It all depends on the turbo Your running if it can handle it. I've seen the TD05 Compressor map. It's loosing efficiency right around 15 LBs and up. That's where the air is getting hotter and You not gaining good boost.

Air to liquid IC's are almost always more effcient.

 

[f-two-fiddy]

Good Reading> http://www.turboneticsinc.com/all_about_intercooling

 

[RedTruck]

Trying to up the boost by keeping the wastegate closed longer is heating the intake charge even more.

I'm not really questioning anything else you've got there. It seems like you've really done your homework, but this doesn't seem right. The wastegate starts out open then closes as manifold pressure increases (or wastegate vacuum increases). To keep the wastegate open longer should increase boost and decrease temperature which is what you can do if your boost numbers are low (ie improperly sized or inefficient air to air cooler).

Paul

 

[ameristar1]

Thermodynamics doesn't work that way. The more boost you run, which means the air is compressed more, the air heats up. It's an inverse proportion.

 

[lpennock]

I'm not really questioning anything else you've got there. It seems like you've really done your homework, but this doesn't seem right. The wastegate starts out open then closes as manifold pressure increases (or wastegate vacuum increases). To keep the wastegate open longer should increase boost and decrease temperature which is what you can do if your boost numbers are low (ie improperly sized or inefficient air to air cooler).

Paul

I think you have the logic reversed. My waste gate is held closed by spring pressure and then when manifold pressure reaches a certain level the spring pressure is overridden and the gate opens to allow exhaust gas bypass. Also as you compress gases heat is created so as you increase the boost you are generating more heat in the intake track. Now if you are talking about EGT you are correct up to a point, increased boost equates to more air which lowers EGT; however, at some point the additional heat caused by compression exceeds the amount of EGT reduction caused by additional air and the EGT's start rising again.

 

[RedTruck]

Holy balls...my bad. I blew that one. I always thought the wastegate was a slider valve on the air outlet side, not a bypass valve on the exhaust inlet side. Thanks for correcting me.

Paul

 

[Slade]

I lost 3 lbs of boost with a '01 power stroke intercooler but gained power and a little lag in the boost is fine with me it's not a race car. It was a very cost effective installation and reasonably priced.

 

[typ4]

bob did you wrap the crossover pipe? That will gain a pound.

 

[FordGuy100]

I dont mind if I loose boost if I can keep EGT's under control. I'm going to tow a lot of with truck the next couple months and I need to be able to haul 5K+ pounds without having to watch the pyro like crazy.

 

[Slade]

bob did you wrap the crossover pipe? That will gain a pound.

No I didn't, I guess that will be a future project. What should I use header wrap?

 

[Slade]

I dont mind if I loose boost if I can keep EGT's under control. I'm going to tow a lot of with truck the next couple months and I need to be able to haul 5K+ pounds without having to watch the pyro like crazy.

I'm towing a 13,000 lb + 5th wheel with the fuel turned up and max out at about 1150. Thats with the pedel on the floor pulling grades in 100 deg weather.

 

[david85]

No I didn't, I guess that will be a future project. What should I use header wrap?

Yup. With some difficulty I heard it can be done without removing the cross over pipe.

I just pulled mine to do it though.

 

[Slade]

Why does wrapping the crossover pipe raise the boost?

 

[towcat]

Why does wrapping the crossover pipe raise the boost?

anytime you can keep the heat content in the exhaust it's a good thing.
BUT in the real world, wrapping the pipe has a potential downside....moisture gets trapped and your pipe will rot out.
as a result, I'll give up a little so my turbo system will last a little longer.

 

[ameristar1]

The turbo gets spun not only by the velocity of the exhaust gas, but also by the heat of it. The less thermal loss you have in the system, the more efficient it is.