Corvair Corsa 180 HP Turbo

miniman82 · Post by **miniman82** » Sun Jul 13, 2008 12:27 am

Here's the MAP I've been working on for a couple weeks.

My engine is not stock: .040" over pistons/cylinders, Isky turbo grind, ported heads, free flowing muffler. Using the wideband, I see that I have AFR's in the 12:1 range under boost, so fuelling is accurate with the YH carb.

This map is for hot weather, to reduce the chances of detonation. Cold weather will allow more agressive advance curves, so I'll post up another one when I've got some decent cold temps to play around in.

Have fun with it, but remember-this is just to play with. If you don't know what you're doing, don't play around. I cannot be held responsible for your engine damage! That said, this should get you pretty close to optimal.

miniman82 · Post by **miniman82** » Tue Dec 16, 2008 2:41 am

Update time!

I've moved to Chicago since the original install, so I've had some time to play around with cold temps. Turns out things aren't so different from the hot weather map, but I was able to add some timing in under the boost/high load areas. The biggest change I had to make was around idle, because it wanted to stall sometimes. Bumped up the idle timing, tweaked the mixture and idle screws, and that's now sorted.

One thing I've noticed is that when temps drop below 30*F, it's pretty hard to get the heads over 300*F. I beat on it till my foot gets tired, and it never goes past 300. While that's a benefit to avoiding detonation, it's a pain because it means the engine never reaches full operating temperature. I'd prefer the heads to hover around 350*F whenever possible, so maybe the next change will be a larger diameter pulley for the cooling fan to slow it down. Never though not enough heat would be an issue with an air cooled engine....

I posted the map I'm currently running with. I'll hopefully be able to put more time into it in the near future, but for right now I'm happy with the way the thing runs. According to a quick datalog, I'm getting an honest 10 lbs boost on a hard run through 4th gear so that's good. It's scary fast in 3rd and 4th, so needless to say I can't wait to swap a Weber/SU on this thing, or possibly go with EFI.

NITROPIXIE · Post by **NITROPIXIE** » Tue Dec 16, 2008 5:20 pm

Just a thought, but could you not cover half the radiator up. Something classic cars used to do in rallies back in the old days. That way the rad wont be as efficient and you should get a warmer engine.

DannyP · Post by **DannyP** » Wed Dec 17, 2008 3:54 am

If it is a Chevy Corvair flat 6, there is no stinking radiator! Corvairs were aircooled, unless a Corvair is some variant of a Mini?

NITROPIXIE · Post by **NITROPIXIE** » Wed Dec 17, 2008 9:57 am

Oops, no type of mini i'm afraid

Alexander_Monday · Post by **Alexander_Monday** » Wed Dec 17, 2008 2:36 pm

Miniman: Since you came from CA, I just had to say welcome to winter.

miniman82 · Post by **miniman82** » Sat Jan 10, 2009 1:16 am

I've lived in the snow all my life bro, call it a return home if you like.

I'm from WI, where I'm at now in IL I'm only 1.5 hours from my folks house.

Nitro- a Corvair has no radiator, it's air cooled. If you want Mini stuff, wait till I'm done building my 1293 A+ lump.... I have a 1972 Innocenti Saloon among the other project cars I have floating around. Just got the block machined, and Mini Spares is posting the gearbox parts as we speak!

Ryanesque · Post by **Ryanesque** » Fri Feb 13, 2009 1:32 pm

Now lets see if my map works!

I don't have it on this computer or I'd post it here.

basically I used Brents basic NA map, and then changed the RPM bins to the same as yours, then changed the kp loads to the same as yours. I added more advance than you (10? I thought turbos were supposed to be like 24!?) across a lot of the scale.. we'll see. i start with around 14º and end with about 36º so we'll see.

now i just need some wire and some brackets...

Ry

miniman82 · Post by **miniman82** » Tue Feb 24, 2009 1:43 am

Ryanesque wrote:I thought turbos were supposed to be like 24* across a lot of the scale...

That's the stock curve with a stock distributor. It makes the engine a bastard on hot restarts, and it's not the best scenario for highway driving, either. 24* isn't enough timing on the freeway (unless you drive at 4000 RPM all the time- you don't get more than that below 4K), and 24* is too much base timing for easy cranking. That's why I lowered cranking timing to 10*, advancing to 20 when it catches and runs. I also added 6* of 'vacuum advance' for freeway situations, but the best thing about MJ is the most accurate boost retard a Vair has ever seen! You can forget about the stock pressure retard can on the distributor, it provides inconsistant timing vs boost pressure at best, and no retard if it has a hole in it at worst. Suffice it to say, I'm thoroughly disgusted with the stock distributor. At least I'll never have to deal with one ever again...