Basic turbo tech questions for a newbie :-)

[Phyrexii]

Hey, y'all,

I have always loved the (relative) simplicity of the Buick turbo system (draw thru, compact, etc), and am interested in using it on a custom setup of mine. However, I am having trouble deturmining some basic info on the turbo itself, and am hoping you can help.

I have a turbo from an 80 or 81 Regal, and I know it's an Air research turbo, but which one? A T03? Are there any compressor maps? What is the A/R? Any other info I may be missing? ;-)

I have several projects that I am trying to work on (who doesn't?) - an 83 VW Rabbit (currently with a 1.6L, but may put in a 1.8), but I'm concerned that this turbo is too big. Also a 72 Skylark, and I have a nice low compression 350 for it, but I'm concerned that the turbo is too small - but I could go with a twin setup, if the turbo isn't too big.

Any help is greatly appreciated!

George

 

[charlief1]

Welcome aboard George. Click on the second link in my sig and you should get some answers. Maps are there to so you should be able to figure out what you need to.

 

[Phyrexii]

Thanks! I saw that thread, but I didn't notice pg 2 & 3! (it was midnight )

 

[Phyrexii]

O.K. - Next question - I've determined that the compressor on the turbo I have is slightly too big for the Rabbit, but only below 3k rpm. The assumption here is that there is enough exhaust speed / energy to spin the turbo up to boost under 3k rpm. I have a hard time believing that a 1.6L engine can do this with the factory turbine, but there is precious little data regarding the turbine side (that I can find), and I don't know how to calculate this for sure.

SO, you guys / gals that are experienced with these turbos, what do you think?

 

[charlief1]

Go to the turbo section and look at the stickys there. that should help you some. As far as "turbine", are you talking about the inducer (intake) or exducer (exhaust)?

 

[Phyrexii]

When I say 'turbine', I am referring to the exhaust side. I read thru the stickys as you suggested, not sure if I am missing something.

It would seem to me that it takes X amount of exhaust flow (or volume) to spin the turbo up to boost speed for a given intake air flow. Because these turbo's were designed for a 3.8L engine, I am thinking (hoping?) that the 1.6L will not be able to flow enough exhaust to spool up the turbo at low engine rpm's (specifically, below 3k, where this turbo will be too close to surge), but at higher rpm's there will be enough energy to produce boost. Or, should I assume that the turbine and compressor are matched such that for any given air flow thru the compressor, there will be enough exhaust flow thru the turbine to make boost? (I am also assuming a steady engine rpm - WOT without actually accelerating (on the highway climbing a long hill, for example)).

 

[charlief1]

Well the first thing you need to realize is that the exducer housing is the problem, not the inducer. The earlier cars have a large exducer wheel and the housing sucks. The first of the SFI cars had a better design and the third with the intercooled engines has the best exducer wheel and housing. An original design T3 turbo should have the same center from the research I've done. I've got the turbo off an eclipse here and no exducer wheel and the center is the same as the others from the Regals, just a slightly smaller wheel and different housing. This might be the way for you to go. If I had the exducer wheel for this particular turbo I'd be building it as a secondary for back up. I may still do it because it has a 4 bolt flange inlet instead of the 3 bolt stock design. Depending on the size and weight of the exducer wheel will determine how fast the inducer side will create pressure in the intake. If the exducer is to large it will slow down the inducer due to the fact that the mass of the whole thing is harder to move overall.

 

[dr_frankenstein]

especially if he trys the earlier .82 housings..... talk about blah!

the .63 might be able to do what you want on that 1.6 but I think your odds would be much better with the 86/87 turbo as charlie suggested because of the improved effcieny.

are you staying draw-thru? because I think that something with out a carbon seal would spool faster on that smaller engine.

A.j.

 

[Phyrexii]

So, it sounds to me that (in my case) this is a good thing (that the exducer sucks), because when I plot my airflow on the turbo map, everything under 3k rpm (engine speed) is to the left of the surge line - the compressor is too large for my application. So, I don't want to generate any boost below 3k rpm.

I figured out that if I put this on, and get surge at low rpm's, I could purchase an rpm window switch and hook it up to a solinoid that will hold the wastegate open until the engine reaches, say, 3500 rpm. I'm still on the fence with this project (the Rabbit), because, while I have the whole thing physically worked out (these turbo's look like they were made for this car), I'm not sure the rest of the car can handle it (but what a blast if it did!).

 

[charlief1]

Well for 1 thing, if you leave the gate open the wheel won't spin near as fast to get you spooled up when you get to 3500. To do the set up justice you really need to down size the exducer and leave the gate closed until you get the boost you're looking for. This would be a good use to go external instead of internal gate. They work much better at getting you spooled up because they only open when target boost is reached, unlike the factory design which opens slowly at lower boost until you reach the maximum boost.

Wondered where you been hiding lately Aj.

 

[Phyrexii]

especially if he trys the earlier .82 housings..... talk about blah!

the .63 might be able to do what you want on that 1.6 but I think your odds would be much better with the 86/87 turbo as charlie suggested because of the improved effcieny.

are you staying draw-thru? because I think that something with out a carbon seal would spool faster on that smaller engine.

A.j.

I plan on using an old (dead) Q-jet as a throttle body, but keeping the CIS injection already in the car - so it will still be a 'draw thru' design from the seal's standpoint. I am using the cold start injector for fuel enrichment, and I am mounting that before the turbo (where the egr valve is (was)). This also allows me the option of switching over to a carb if the FI isn't up to the task (Imagine a Rabbit with a Q-jet sticking out of the hood! MWAAAHahaha!)

Also, if I choose to abort this project, I will switch focus over to my Skylark, which will be draw thru (although I will need a twin setup, and a little more engineering).

Ultimately, for the Rabbit, I am not looking for super high power. Ideally, I only want to produce maybe 120-130 hp, and I'm happy if it doesn't get there till the upper rpm's. I know I could simply get a T25 which is much better matched for this engine, and set it up as a blow thru, but how much fun is that?

I LOVE turbo's, but this is my first project (I used to have a 300ZX turbo). I'm just having a little fun here...

 

[dr_frankenstein]

Well for 1 thing, if you leave the gate open the wheel won't spin near as fast to get you spooled up when you get to 3500. To do the set up justice you really need to down size the exducer and leave the gate closed until you get the boost you're looking for. This would be a good use to go external instead of internal gate. They work much better at getting you spooled up because they only open when target boost is reached, unlike the factory design which opens slowly at lower boost until you reach the maximum boost.

Wondered where you been hiding lately Aj.

I reckon that those compressor maps are kind of funky, something is not quite right. I have seen the stock .63 housing on VWs before, not inline, but aircooled flat 4s. A local buddy of mine is working on one now... and a friend in cali has one successfully running. So thats a little food for thought.

where have I been hiding?................................

uh I have mostly busy with those stupid plates I contracted them soldiers to build. it turned out to be really hit and miss.... some look like they were machined with a hatchet, or some were wicked out of tolerance.

if you want something done right, do it yourself.... been trying to learn how to use a CNC mill without any kind of CNC experiance..... LOL I can machine..... just nuthing this fancy!

A.j.

 

[Phyrexii]

if you want something done right, do it yourself.... been trying to learn how to use a CNC mill without any kind of CNC experiance..... LOL I can machine..... just nuthing this fancy!

A.j.

A.J. - a little off topic here, but you might want to check this out:
Sharpening Skills in Online Classroom

This 'school' has virtual classes in everything machining, and it's not too expensive (I think it's $64 a month with 3 month min, but for schooling, that's a bargain - IMHO)

 

[charlief1]

You don't need to use a cnc Aj. All you really need is a decent mill and a turn table set up. Not hard at all. To make the concentric part you can use a small lathe about 6" should do fine. You need some more time in shop class bud. lol

 

[dr_frankenstein]

LOL, thank you gentlemen both very much!

im on the cnc because once its set im looking to make 20 of the T04B/E/S plates at a time so a total of 60 units would take forever by hand.

now as I quit hi-jacking....

for the 1.6, I do have a small 4 bolt turbo from a toyota I reckon? that has the identical compressor wheel and housing as the buicks, but has a super tight .63 housing that looks better on the exhaust side than the 86/87 units.... I can find out more if interested....

for your 350..... with twins.......... the stock 86/87 turbo will be a perfect choice, carbon seal, good size compressor, tight turbine........ I think it would spool fairly fast and make solid boost for a V8.

:biggrin:A.j.

 

[charlief1]

The only addition I can think of on the 350 is if my turbo project works as well as I think it should then I'd go this way for better boost. Smaller exducer and a much bigger inducer would allow for better charging of the engine for sure.