I'm thinking about getting an intercooler for my 280zx turbo. About how much of a horsepower gain should I expect out of one?

 

On stock boost, not too much. If you start upping your boost though, you can see considerable gains over not running one. It's not so much that the intercooler adds horsepower (maybe a little because the air is denser), but rather it allows you to run more boost by lowering intake temps (reducing detonation). When the turbo compresses that air, it gets hot, which no good, starts causing detonation. So an intercooler is more of a safegaurding neccesity rather than a power adder. You should definitely get an intercooler though. Especially if you're going to be increasing horsepower, which sounds like you will be doing.

 

And by the way, raising boost is the single biggest power gain you can give your engine. You just have to be careful or you'll be throwing rods out the side of your block.

 

Just make sure you remember bigger is not better in this case, to much pressure drop will take power away.

 

BIG turbo=BIG intercooler, little turbo=little intercooler. (should actually be figured by amount of boost but you get the picture). Also another thing to consider, is that the bigger you're intercooler the more it's going to restrict air flow to the radiator, which can overheating if you're running the stock radiator. That's why you see the JGTC cars running a V-mount setup, so both the IC and Radiator have unrestricted airflow.

 

well, when i read the owner's manual ( yes, i actually read it) it said that anything over the stock boost pressure will cause damage to the intake manifold. is that true? if not, what is the maximum safe boost pressure if i were to get an intercooler.

 

is the owner's manual just saying that for people who think they need 21 psi of boost on a completely stock engine?

 

owners manual states that for their protection...yes it CAN damage it if done improper...
safe are is 10 pounds on stock everything..i woudlnt go more than that, your EFI starts leaning out and could be dangerous

 

There was a guy here in AZ running 12PSI with everthing stock, and his safty valve caught on fire and sealed itself shut..

 

The owners manual also warns against aggressive driving. That is a waste of gas and money. Drive slow and easy.

 

The only part of the manifold you would damage with too much boost is the POV. It would take a whole lot of boost to split that manifold, more than your engine will ever handle.

 

he has to be running more than ~12 psi otherwise hes got cooling problems.. i run 12 psi and i kick *** left and right.. but i also have evrything in good condition.. and is his POV stock or is it modified.. mine opens up at around 12-13 psi.. otherwise the compressed air could just be heating it up and causing it to melt

 

could you tell me what type of aftermarket b.o.v. or p.o.v. or boost controller i can buy and where to get one. Everywhere i look i see that they're universal and I don't want to get the wrong one.

 

If the pop off valve is the pressure relief device located on the intake manifold, I've seen aftermarket relief valves from HKS and Greddy.

 

You aren't likely to find a direct replacement for the L28, could be though. Most applications are universal unless they come in a kit. There are tons of manufacturers out there, just go with one who has a good reputation like the ones Heat Rave R suggested. If you get in contact with them they'll size you up right, though that shouldn't be a problem on a stock engine. When you start running high boost, you're going to need one that has a higher flow rate and stronger springs/diaphrams. As far as boost controlers go, I'd recommend those same two companies. Apexi makes good electronics as well.

 

I have a quick question about the HKS intercooler. I know its expensive but I'm just a kid and don't think I could handle making my own set up. Does anyone else have the HKS and I'm guessing it doesen't, but do they come all setup with a BOV already? Also will it be a restriction in the future because I only plan on going for around 300hp down the road.
Thanks
Rob

 

No on coming with a BOV. Unless you get a whole turbo upgrade kit from HKS (they don't make one for these cars) you'll have to get it seperately. You'd also have to eliminate the POV on your intake manifold when you upgrade to a BOV. They do the same thing, but you only want one otherwise you might run into premature evacuation issues from the stock peice. As far as the intercooler itself goes, with 300hp you definitely want an intercooler. But you don't need a huge unit that's going to completely inhibit flow to the radiator. Get in touch with HKS, or other companies, and they'll point you in the right direction. You want to get one that's not so dense that no air will flow through it, or else the radiator isn't going to get enough air. The really dense ones are more so for if you do a V-mount sort of setup or drag racing where the radiator isn't going to be an issue. Your horsepower goals are reasonable and the intercooler is only there to prevent detonation by cooling the intake air. Too big, and you'll loose pressure. If you're running off the stock turbo or something small then all you need is a small intercooler. Like I said, talk to or email one of the manufacturers and tell them your plans as far as power goals and turbo setup and they'll be able to recommend something. They're not going to tell you to buy the biggest IC they have because they know you wont be happy and that looks bad on them.

 

I didn't think it would come with a bov but it should for over $1200. But I don't see why you would have to eliminate the POV. I always thought the bov and pov were 2 completely different things. The pov protects you incase your boost spikes up or something then the bov protects the turbo. I'm probably wrong though
Rob

 

Same deal. The BOV protects the turbo against compressor surge. All that is is when the compressed air hits a stop and tries to work it's way back to the turbo. With the POV, the air gets trapped in the manifold and has no where to go, so the valve opens up and relieves the pressure in the manifold. The POV doesn't prpvide any protection for the turbo however when the throttle is closed. Not good, especially when running high boost levels. With the BOV set before the intake manifold the pressure is eleviated before it ever reaches the manifold therefore eliminating the necessity for the POV. I don't know what the stock POV can handle as far as pressure is concerned, but an aftermarket BOV will handle much more pressure without a doubt. So in that scenario running higher boost than the POV can handle, if you keep it, you wouldn't be able to run full boost. But again, I don't know what its max pressure capabilities are. So you're not wrong, they both protect against boost spikes, but only one protects the turbo

 

Oh, and it's only $1200 because it's HKS. The name costs more than the product. BUt atleast you'll know its a quality unit.

 

Oh, I figured I was probably wrong, I usually am. So I take it if you just plug off the POV you would be fine right? I don't plan on getting the intercooler any time soon anyways, I probably won't have the money untill next spring.
Rob

 

Yep that will do er. Just make sure it's not leaking when you seal it off. Good luck on your mods. And I wouldn't say you were wrong, you just didn't have all the info. In fact nothing you said was really wrong, so don't knock yourself. And you can keep the POV with the intercooler and the BOV for that matter until you start to exceed the limits of the POV.

 

I have a friend running 24PSI w/water injection on a stock motor

 

Wow, is that a 280zx?

 

No its a 260 with an 81 turbo motor in it.. It is rediculous, he is the inspiration for my project I have alot more motor work done and will be running the same turbo setup so I am hoping for his power at lower boost.. Also he has ran that setup for 2 years now, and has only blew one headgasket..