Intercooler or Meth injection.

[madolive3]

I'm relatively new to this forum and I haven't mastered the search function yet, but I did try. This is not a which one is better question..... My question is for you CA. S30 owners. I have a 77 that I will be putting a 83 l28et into. I would like to be able to boost up to 14-15 psi. Of course at those levels I have to cool the charge. I don't think an IC will pass a visual here in CA. I know there are some CA guys here with IC, how do you do it relative to smog? I'm thinking a Ho2 inject system would be less noticable and take up less room under the hood....

Thanks Bill

[datz280]

I also have a 77 that will need to pass smog. I don't have my swap done yet. When I mount an intercooler I was thinking of keeping the stock J pipe and swapping it in for the smog test. At that point the intercoler is there just for looks.

[cockerstar]

I wouldn't be running 15psi on water injection only. Cooling the air charge via intercooler lets you make the charge much denser before it hits your intake resulting in more 'umph' at the same pressures.

[Brad-ManQ45]

You should have no problem passing emissions with an intercooler, which is before the fuel/air mixture part of controlling the engine.

 

It has the added benefit of taking thermal stress off the engine.

 

I personally wouldn't contemplate H2O or methanol injection until I got over 15 lbs of boost.

 

THe main reson for this attitue is that up to 15 lbs boost, assuming that one has an adequate I/C, yuou DON'T NEED anything else.

 

Without the I/C, you are somewhat limited in how much boost, and even if you use some gorm of liquid injection, you have to be sure you DON'T RUN OUT of the cooling liquid.

[datz280]

You should not have problems with tailpipe emissions. But in Calif. you need to pass a visual as well. As I understand the rules anything that alters the air or fuel that was not there stock will cause a person to fail.

[proxlamus©]

Intercooler...

 

it always works.. its cheaper.. there is no pump to go bad.

 

Meth costs money every time you fill up. why bother?

[jgkurz]

My opinion is you should definitely get an intercooler first then add methanol injection if needed. An intercooler is a core component to any well built turbocharged engine. Case in point, look at all the OEM engines with turbo's. Most have intercoolers with no other charge cooling mechanism. Methanol should considered only if you can't run your desired boost with only an intercooler.

[Tony D]

To answer the question about the SMOG check--which I think it the pivotal point:

Turn your boost down, and stick your J-Pipe back on it. Paint your intercooler black so it doesn't draw attention. As long as the system remains 'as manufactured' it will pass the visual. It will be one day out of every 730 that you will have to run that way. Shouldn't take you 1/2 hour to accomplish, and then stick it back on.

 

If it's connected, and it doesn't have a CARB EO # on it, they can fail you on the visual (and paranoid techs these days will not hesitate to do so and most 'check only' stations, and you will have to go to a referee...

 

Do you want that hassle?

 

For the hassle once every two years, just swap the J-Pipe back on and pass the SMOG Test.

 

Now, as to 'either or' it all depends on how hard you boost and how long. It's not like you have a Saab with a 2.5 gallon windshield washer tank hidden inside the left fenderwell... your methanol supply will be limited, and the more you boost the more you use. So if you boost early, and boost often it can be as much of a drag as refilling a NO2 bottle...

 

A proper intercooler can be integrated and cool you fine to stratospheric levels, and methanol will add some power at the upper ranges.

 

I ran 21 psi with no intercooler, and the old Reliable Spearco Water Injection unit running ethanol/methanol/isopropyl/water for years on both my early Turbo Z and that was after I took the unit off the Corvair which had it on there forever (er...like installed some time in the 70's or early 80's!)

 

I don't know about people saying liquid injection will 'limit' your boost levels, Multistage turbosystems on pulling tractors run water injection through four stages of external compression to boost levels of over 150psi in the manifold. It's all a matter of each stage compressing and adding heat. And when you add heat at pressure the amount of water the air can hold in suspension goes up each time. If you start out with a low relative humidity your first stage can inject a LOT of water for heat removal. I think the 'limit your boost on liquid only' is a spurious contention.

 

Clear as mud now? LOL