southern boost
Member
- Joined
- Feb 23, 2002
hey guy you need to listen to steve, azgn. they r pretty swift on these cars and what they are sayin is correct. I just bought my gn and having to learn alot but i have tech. for years on cars. i know one thing these guys are very smart on their tips and they dont talk for the heck of it so listen.
Steve Wood
Active Member
- Joined
- Jul 18, 2001
Originally posted by southern boost
. i know one thing these guys are very smart on their tips and they dont talk for the heck of it so listen.
Well, AZGN is a man of few words and he really knows his stuff. Me, I am fuller of it than any Christmas turkey!
Steve Wood
Active Member
- Joined
- Jul 18, 2001
Originally posted by Quickturbosix
Hey Steve do you have a map of the 45? I just talked to John Craig about this last week. I think the 45 would be in the surge zone at 16psi. The 63 might work out better, depends on its map. But being smaller then the 45 the surge zone should be lower.
Is this the correct thinking???/
Still trying to figure this tr stuff out...2 GN's later
I have the original 45. John brought out the 45A about a month after I got mine. I have never seen a map. I kinda doubt anyone has taken the trouble to make maps for most of these "Mix and Match" turbos.
Where I have problems with surge is at very light throttle coming up a freeway ramp or easing by someone at speed. When the boost is between 0-5#, and the throttleblade is maybe 20% open, it goes into never-never land and is shaking and sputtering and will not accelerate until I lift and then give it a bit more throttle. It is not a problem at lower speeds or when I give it a healthier dose of foot. You can hear the the turbo chattering and trying to spool. It happens more when I am in traffic and have to ease into the pedal rather than being able to drive it like it was built to be driven. I think I am usually around 2000 rpm in third when this happens.
I have heard a number of others with similar experiences. It just wants more air.
This size of turbo is on the lower end of "Race" and we are pulling the surge zone into our operating band on the street, I think. It's a great turbo!
Steve Wood
Active Member
- Joined
- Jul 18, 2001
Okay, Do you have TA heads, or GN heads on the TA block?...If yo have GN heads, unless someone decked the heck out of them, You are running lower compression than most of us. That means you need more air into the cylinder than the rest of us to get the same power. This may make the car a bit slushy on the street at low speeds.
In general, I would think you have a pretty good combination, but, I think your injectors are a bit small for the size of turbos you are looking at. Altho I run 75# injectors, 65# units would probably be pretty ideal for a 45 size turbo that was going to be twisted to 26# or more of boost.
You did not say what converter you are running but it is very important to match the converter and turbo if you want to enjoy the car.
If you want to push the 530-540 hp that I think is practical for an ungirdled block, I think something in the line of a PTE53, 54 would match very well. This will put you into the tens unless you weight about 400#.
A PT 53 is rated at 610 hp and the 54 at 620. Your 55s will match up well with the 53 and I would suggest 65s for the 54.
I would suggest a 3200-3400 rpm stall converter that would allow you to build at least 10# of boost against the brake without taking all day to do it.
If you want to step up to a 45A or 66, then I would suggest 65-75# injectors, and a converter that will allow you to pull the 10# of boost at 3500-3600.
Just be warned that the 53 up are capable of flowing enuf air to blow the crank out the bottom. The smaller the turbo, the more fun the car will be to drive in every day traffic.
These cars are all about combination. If you get one thing out of line with the rest of the parts, they don't work as well.
K
KwikerSilver
Guest
The heads are Buick heads, and i wanted lower compression. The convertor is a o pump 5 disk vig that i think stalls at 3200.
The only way an engine makes power is by pumping air. And there are just a few ways to get more air through the engine. Easy way, turn up the boost! 20 pounds will push more air through the engine than 16. Period. Next, turn up the rpm. But that puts more strain on rods, crank, etc. and requires more cam, which kills low rpm power. Either of the above is helped by porting and polishing, and a better IC will cool the air more, making it denser, thus more power at the same pressure. Finally, as the saying goes, you can't beat cubic inches. But a bigger turbo will NOT flow more at the same pressure. The engine will only take what the engine will take. If you want to feed it more, you have to up the boost, up the rpm and/or improve the flow path by P&P. Oh, you could run on alky, it takes less air for a given horsepower, and will respond to all the above.
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