Proper size turbo for Northstar

[eHoward]

I really hope you buy this turbo, get a good tune, run 9s and make the rest of the junkyard saab turbo buying fiero owners look like the dipshits they are.

I knew you were concerned with negs hehe

I looked on e-bay and there is a GT42 for $1000us, about what I expected to pay for the turbo. I will be looking as soon as I finish my swap, start buying parts.

[Aaron]

Go with the ball bearing unit, trust me.

I'd rather have a ball bearing turbo than an intercooler, let's just leave it at that.

[crzyone]

We'll see. As far as having a BB turbo, definitly quicker spool time, not sure if its worth the extra cash though. Will have to shop around.

If I could get into the 11s I would be happy, thats a wicked fast car.

[Aaron]

It's worth every penny. It isn't just faster spool, they typically run 4-6% higher efficiency's, and are much smoother.

My friend has a 1998 Cavilier Z24 that we turbocharged a while back. We then converted it to the same size unit, but ball bearing. You wouldn't imagine the power gain. It spooled off idle, and pulled stronger and stronger up to 6500rpm. It was the correct sized turbo, and the old one didn't spool until 3000, and the new one did at aout 1500. Plus the lag was all but eliminated. Say 5000 rpm, he'd slowly get on it, and by the time his foot was to the floor, it was at max boost.

[eHoward]

This has been bothering me and I hoped someone else would say something.

The two are not mutually exclusive. You can have both an intercooler and a ball bearing turbo.


I also could see why he might want to save a couple bucks up front and not do the BB and maybe later change out center cartrige for one down the road.

I would take the intercooler any day of the week on a street car over a BB unit. There's a reason why the OEMs use intercoolers on everything, but not ball bearing turbos.

I can do the math, but he's going to give up roughly 50 horse by not using an intercooler while increasing wear.

Go with the ball bearing unit, trust me.

I'd rather have a ball bearing turbo than an intercooler, let's just leave it at that.

[Aaron]

This has been bothering me and I hoped someone else would say something.

The two are not mutually exclusive. You can have both an intercooler and a ball bearing turbo.


I also could see why he might want to save a couple bucks up front and not do the BB and maybe later change out center cartrige for one down the road.

I would take the intercooler any day of the week on a street car over a BB unit. There's a reason why the OEMs use intercoolers on everything, but not ball bearing turbos.

I can do the math, but he's going to give up roughly 50 horse by not using an intercooler while increasing wear.

Go with the ball bearing unit, trust me.

I'd rather have a ball bearing turbo than an intercooler, let's just leave it at that.

I didn't say you can't use them both, I just said I'd rather have the BB turbo. After turboeing a street daily driver, and driving it for 6 months, then going to a BB turbo, trust me, I'd rather have that than the I/C.

Have you driven a turbo car everyday, then upgraded to a BB turbo? I have, and trust me, I WAS AMAZED.

That is the reason factory cars use intercoolers, not BB. First of all the shitty I/Cs they use are really cheap, and secondly, using an I/C is a lot better on the engine, and in factory cars that are going to be abused, but stillneed to last forever, this is important. But if you are tunign it perfectly, and keeping up on maintenance, it will be fine (assuming detanation is kept at bay). But if this were not an issue, I guarantee they'd use BB turbos. It'd be soooo much easier to sell a turbo car that spooled off idle, yet still pulled, and stayed efficient, to 7k. But this is why a lot of people hate the STi, Evo, and DSMs, it takes until 3-4k to get the things moving.

[crzyone]

I would use some sort of intercooler. Air/water, air/air or water/meth injection. Air/air would be pretty pointless in a fiero. Why do you guys dislike water/meth? On top of cooling the charge, the methanol also increases the octane and is more resistant to ping.

Quick spool is a non issue when you have 300lb/ft off boost, plus it would only take part of 1st gear to spool, the rest of the gears would have max boost anyways. Were talking less than a second I bet to spool that turbo.

[Aaron]

Any lag is bad lag. You don't think you hate lag until you don't have any.

The BB will also add power, as they are more efficient, and draw less HP.

[Shaun41178(2)]

The bearings themselves dont' make them more efficient. It allows them to spool faster and accept much higher loads. its the shape of the wheels that make them more efficient.

The GT wheels are just a better wheel and the GT series are normally ball bearing. There are quite a few companies however that offer GT wheels in standard journal bearign setups to help save on the cost.

You will have a n star with 300 lb ft. Lag in that setup is a good thing. It will be fast enough without boost.

Jon tells me his nstar roasts them when the rpms hit 3500 in first gear without a turbo at all. I think he wears 245's in the rear on 17's.

Lag on a nstar is fine.

Just worry about getting it installed and tuned for now. One thing at a time my young padowan.

[eHoward]

WHy don't I like it? Because when you run out of it and you're running a map that's dependent on it bad things happen.

If this was a grassroots car where you're cutting corners to save every penny, I'd approve. but not for a street-car.

I don't think an air to air would be pointless if done right. It will take some effort to do right. The air to water is the easiest to do right. Hopefully Jon will post some pictures of his air to water setup.

I would use some sort of intercooler. Air/water, air/air or water/meth injection. Air/air would be pretty pointless in a fiero. Why do you guys dislike water/meth? On top of cooling the charge, the methanol also increases the octane and is more resistant to ping.

Quick spool is a non issue when you have 300lb/ft off boost, plus it would only take part of 1st gear to spool, the rest of the gears would have max boost anyways. Were talking less than a second I bet to spool that turbo.

[The Dark Side of Will]

Padawan.

Having a Y2K engine will help with the boost issue. The Y2K engines had subtle chamber tweaks and a slight drop in compression (10.5 - 10.3) so that they could make full rated power on 87 octane as opposed to 91. That means that when boosting the engine you have an extra 4 points of octane rating to play with while still remaining on pump gas.
The Y2K cylinder heads also ought to be more turbo friendly than the earlier engines. The early engines have perfect intake/exhaust flow ratio for N/A performance. The Y2K engines have upgraded intake ports but compromised exhaust ports such that the port flow ratio is better suited to turbo use.

1st gear with a turbo will be useless for everything but parking.
Does the Y2K intake manifold have a backfire valve like the early manifold? It would be a small flap on the end of the manifold opposite the TB. It will have a small spring holding it closed, but will lift with a few inches of positive pressure in the manifold.

[Aaron]

The early engines have perfect intake/exhaust flow ratio for N/A performance. The Y2K engines have upgraded intake ports but compromised exhaust ports such that the port flow ratio is better suited to turbo use.

Do you know the ratios off hand?

I'd also like to see flow charts!

[Shaun41178(2)]

Any lag is bad lag. You don't think you hate lag until you don't have any.

The BB will also add power, as they are more efficient, and draw less HP.

I have been corrected off the forum and I guess this is true. You were correct. thanks Howard

Ball bearings in essence would make it more efficient(even if not reflected in the comp map) as it would take less hp to spin. Less friction would mean more overall hp. Not sure if its a measureable amount though or if that amount is worth the extra $500 price tag for BBs

I would go air to water. As small as the bolt on kits for the 3800 are, they drop temps by 100 degrees. Before the intercooler the outlet temps on the blower were at 300+ degrees. After its down around 220 ish I think.

So even a small air to water would be better then nothing. With an air to water you can practically put it anywhere.

[Aaron]

Any lag is bad lag. You don't think you hate lag until you don't have any.

The BB will also add power, as they are more efficient, and draw less HP.

I have been corrected off the forum and I guess this is true. You were correct. thanks Howard

Ball bearings in essence would make it more efficient(even if not reflected in the comp map) as it would take less hp to spin. Less friction would mean more overall hp. Not sure if its a measureable amount though or if that amount is worth the extra $500 price tag for BBs

I would go air to water. As small as the bolt on kits for the 3800 are, they drop temps by 100 degrees. Before the intercooler the outlet temps on the blower were at 300+ degrees. After its down around 220 ish I think.

So even a small air to water would be better then nothing. With an air to water you can practically put it anywhere.

Exactly, their added power comes in less hp draw, which is not reflected on compressor maps (tho it should be). $500 is a lot, but IMHO totally worth it. The difference was AMAZING.

I too would go air/water, like a Vortech unit. It is just a 8" x 8" x 3" square rectangle, with an inlet one side, and outlet the other.

[The Dark Side of Will]

WHy don't I like it? Because when you run out of it and you're running a map that's dependent on it bad things happen.

How often do you run out of gas? Can easily use a water/alky tank large enough to last for several tanks of gas, depending on usage level, of course.
When you run out of gas, your engine stops. When you run out of water/alky, your engine blows up. Do you think you'd EVER let that level get low enough to cause a problem?

[Aaron]

WHy don't I like it? Because when you run out of it and you're running a map that's dependent on it bad things happen.

How often do you run out of gas? Can easily use a water/alky tank large enough to last for several tanks of gas, depending on usage level, of course.
When you run out of gas, your engine stops. When you run out of water/alky, your engine blows up. Do you think you'd EVER let that level get low enough to cause a problem?

When you aren't used to it being there, and rarely fill it up, yah. I agree, in a way you are asking for problems, and you will be much better off, in power and reliability, with an air/water, even if it costs more.

This isn't the project to go cheap on. As I say oh so often:

Fast, Cheap, Reliable. Pick two.

[crzyone]

Good info so far, thanks guys.

There shouldn't be much heat at 5-7psi, not like running 15+. I will run an air/water. It should be fairly cheap to do. A small car rad, hoses, small electric pump, the only pricey item is the intercooler its self.

I had an 85 turbo Lebaron with a 3 speed auto. I know allll about lag. I would be concerned if I had a 4cyl with 100lb/ft off boost, but with 300lb/ft I'm not overly concerned about it. The GT42 will harldy have to work to make 7psi.

Padawan.

Does the Y2K intake manifold have a backfire valve like the early manifold? It would be a small flap on the end of the manifold opposite the TB. It will have a small spring holding it closed, but will lift with a few inches of positive pressure in the manifold.

It does have an opening at the back, the hose connects to the valve cover. Looks like it can be plugged fairly easily?

You can see where the hose connects to on the left valve cover. I imagine its like the pre 2000 engines.

[crzyone]

This isn't the project to go cheap on. As I say oh so often:

Fast, Cheap, Reliable. Pick two.

Definitly not cheap. Definitly going to be fast... Not to sure about reliability though.

My ecu cost more than my entire 3.4dohc swap.

[crzyone]

Wow, they are more expensive than I thought.

PWR barrel intercooler 6" diameter with 3" inlet and outlet can flow up to 920cfm.

2510062 6" x 10" (19" Length) 920 CFM $805

2508062 6" x 8" (17" Length) 920 CFM $705

2506062 6" x 6" (15" Length) 920 CFM $605

Since I will be running low boost with an efficient turbo through a big intercooler I think the 15" should be be plenty. What do you think?

[Aaron]

I totally agree.

And yah, that is REALLY expensive. But it will pay off, trust me. You will be breaking many a engine mounts :la:

Furthermore. What I meant byt he cheap part. You can still go cheap on this project. Cheap isn't cheap in general, it is cheap on any 1 part. Like fixing your car with dimes (Even though quarters would work better...lol).