turbo question

Topic: turbo question (Read 953 times) previous topic - next topic

turbo question

March 14, 2009, 05:40:45 PM

Hey I am going to buy a T3/T4 for the tbird and was wondering is .60 A/R trim and a stage 3 garrett wheel is going to be overkill?

I am shooting for about 350 whp but want something I can grow into.

I will be using a front mount and 3 inch exhaust.

Also looking for a ranger cam or better.

Any help is appreciated thanks! :hick:

turbo question

Reply #1 – March 14, 2009, 06:03:24 PM

At that power level, 35# injectors probably aren't going to cut it. Just something else to think about. I've heard great things about Boport cams. I have a ranger roller in my car simply because it was cheap and my stock slider was wiped out. I'm saving for something better.

turbo question

Reply #2 – March 14, 2009, 07:20:35 PM

Thanks for the info! I will keep those injectors until I get into the higher boost/horsepower levels.

turbo question

Reply #3 – March 15, 2009, 12:52:05 AM

get a wideband. Best money ever spent. I maxed out the injectors or VAM with 12psi out of my holset at 5K rpm. Just something for you to be aware about. I also like my boport cam, but I wish it would pull a little more vaccuum. I have the 1.9 and his springs. I just got 30psi out of that turbo last night being the first time I drove it this year:)

turbo question

Reply #4 – March 22, 2009, 08:20:30 AM

Which turbo exactly are you talking about?

I have a tO4E 50 trim compressor and a t3 .63 stage 3 wheel turbo and think it's great. Mine's all Turbonetics, but the Precision SC50 is the same thing.

I agree that the stock injectors WILL be too small, and you will need to have a wideband to keep track of AFR if you don't want to be changing headgaskets. Your stock injectors are rated at 36# at 39 psi. When you shop for injectors, you'll find them all specced at a given flow at 42 psi. which is the standard. I'm not sure what max size you can run on the stock computer since I run a Megasquirt (since 2002). Some guys will jack up the base fuel pressure to compensate for a small injector, but suffer rich idling and can run out of fuel pump at high boost since the pump's efficiency plummets at high pressures. I can idle my 65#ers (just) at 12-1 AFR with my base pressure lowered to 32 psi. That gives me an effective 60# injector and a max fuel pressure of under 60# at 25 psi boost. That keeps my pump happy.

I have run a stock Ranger cam, and hated it. Much worse than a good stock TC slider, IMHO. I have a reground higher lift Ranger now, and I wouldn't bother doing it again. It's just OK. If your stock slider cam is in good shape, it's actually a pretty good cam. Just run oil that has some zinc in it.

If you are going to do it, go ahead and get something with more lift and make the necessary valve guide mods to use it. Bo's cams get good reviews.

Better valve springs are essential. The better the intercooler, the less fuel you have to throw at the tune to keep from detonation. My Porsche IC allows me to run a 12-12.5 to 1 up to 25 psi with never a ping. With the old T3 I had to back off a ton of timing and lower the boost to keep from pinging no matter how fat I made the mixture. The 50 trim hybrid makes a world of difference in the amount of COOL air it makes.

Just a few thoughts!

turbo question

Reply #5 – March 22, 2009, 02:48:21 PM

Cool thanks for the info!

The good thing about being at 6500 FT / or higher is that I can run more boost with less fuel because there is less air here. I guess I will have to tinker with my own formula. I am running a .60 trim garrett stage 3 t3/t4 with a .63 hot side right now

turbo question

Reply #6 – March 22, 2009, 05:26:19 PM

Which wheel in the compressor? That sounds like a ~53 lb compressor side, may end up being on the large side for your combo. It will support roughly 550 HP if I recall. Might be a bit laggy for you. Try it and see, though.

Once it comes in it should pull crazy hard to the redline! The effective power band might just be squeezed down far enough to take the fun out on the street.

[SIZE="2"]The good thing about being at 6500 FT / or higher is that I can run more boost with less fuel because there is less air here.[/SIZE]

Not exactly true. At your elevation the boost gage will read less than 0 before you start the car, but it is still calibrated to atmospheric standard. (roughly)

25psi of pressure in your manifold up there next to the Rockies is the same as 25 psi down here at 1200' and the fuel requirements are the same in that part of the map.

What will happen is that your turbo has to consume more of the thinner air to get the same 25 psi built up than mine will. I'm sort of pre-pressurized if you will.

In other words, every rotation of the compressor at altitude can do less work, much like an aircraft propeller as you climb to thinner air.

good reading before spending your money

Reply #7 – March 22, 2009, 06:31:42 PM

http://www.turboford.net/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000050

Corky Bell's book is a good choice if that isn't enough info.

turbo question

Reply #8 – March 25, 2009, 02:53:56 AM

Quote from: flylear45;263285

Which wheel in the compressor? That sounds like a ~53 lb compressor side, may end up being on the large side for your combo. It will support roughly 550 HP if I recall. Might be a bit laggy for you. Try it and see, though.

Once it comes in it should pull crazy hard to the redline! The effective power band might just be squeezed down far enough to take the fun out on the street.

[SIZE="2"]The good thing about being at 6500 FT / or higher is that I can run more boost with less fuel because there is less air here.[/SIZE]

Not exactly true. At your elevation the boost gage will read less than 0 before you start the car, but it is still calibrated to atmospheric standard. (roughly)

25psi of pressure in your manifold up there next to the Rockies is the same as 25 psi down here at 1200' and the fuel requirements are the same in that part of the map.

What will happen is that your turbo has to consume more of the thinner air to get the same 25 psi built up than mine will. I'm sort of pre-pressurized if you will.

In other words, every rotation of the compressor at altitude can do less work, much like an aircraft propeller as you climb to thinner air.

Cool should be nice. Considering the IHI was only boosting 5lbs. I should enjoy this turbo no matter where it starts spooling.