lag time

[Guest hgray14]

How much difference in lag time is there going to be between a .54, .63, .81 and 1.00 A/R on a t3/t04 turbo? I will be running an '81 turbo engine in my 72' 240z and am curious as to how long I am going to have to wait for spool up. Like most everyone, I want to be able to blow away the 'Stangs at the stoplight as well as get some killer top end power and am trying to get a feel for what kind of compromises I am going to have to make to have either one or the other.

 

Also, I keep seeing t3 and t4 turbos on e-bay. How hard is it to make my own t3/t4 hybrid?

 

thanks again for all the help. I am new to turbos and want to get it as close to 'right' for my application on the first go around. ...then again, I do have another '72 sitting in the back yard so I guess I could do it all over again.

 

Houston Gray

hgray14@aol.com

[Lockjaw]

There are only 4 turbine housings for the T3, unless you get some of the new garret stuff I don't know about yet.

 

There is a .36 ar, .48, .63, and .82 . Those are the standard housing's. The stock turbo is a .63. The smaller the ar, the faster the turbo spools. I would not go below a .63. It is probably the best all around turbine housing for the Z car and a T3.

 

If you are going to get a hybrid, I would recommend a stage III turbine wheel, and a V trim compressor wheel, or the H3. I have the H3. I could not get the perfomance out of the H3 I wanted until I got over 12 psi. If you are not going to intercool your car, I would stick with the stock turbo. With an intercooler, the stock turbo is supposed to make about 245 hp at the crank.

 

You will need some way to add fuel enrichment to your car with a hybrid turbo if you run much over 10 psi, IMO.

 

You would be better off to buy a turbo from someone who knows what there are doing.

 

http://www.mjmturbos.com/ try this link and look around he has several differnt turbos with pricing. If you use a T04B, it fits pretty well, depending on turbine housing, the T04E may require a spacer. T04E is a better housing if you plan on running alot of boost, T04B is better if you stay under 20 psi.

 

I have the B housing. I dyno'd 307 Hp to the rear wheels at 21 psi. I don't know what that works out to at the crank. Probably about 375 or so. A V trim would not be far from that.

 

Good luck.

[Guest hgray14]

Thanks Lockjaw,

 

Your reply helps to clear some things up for me. I have seen a lot of numbers listed for turbos other than what you listed so I guess they are either running something custom, did the math themselves or just don't know what they are talking about. I will be running an intercooler and will be looking for a lot of power. The .63 sounds like the best bet my first time around.

 

thanks again

 

houston

[Lockjaw]

Well they could be talking about the T4 housings, and Garrett does have some new ballistic housings that are creepnig into the market, mainly in their ball bearing turbo's. Those are pretty pricey, although they are cheaper to buy from Ray Hall in New Zealand. At least from where I have looked.

 

You will like the hybrid. They make lots of power for their size. Intercooling is a very good idea, and a 3 inch exhaust will really wake things up for you. Be sure it put you K&N filter in front of the radiator so the turbo is injesting cold air, and get a blow off valve.

[Tony240ZT]

Something I noticed about my t04b/t3 hybrid is that the car isn't so freaking touchy now. Before I would give it a little throttle and boost would sneak up on me quick and the car would act like I put my foot into it. Pretty jerky effect, I guess the larger 65mm throttle body played a large part in this combined with the small compressor. This quick respons I had lead me to believe I would have a lot more power if I gave it the rest of the pedal, but nope, not much left after that uncontrolable peak.

Now the car is much more driveable on the streets. Boost is much more predictable and the trasition is smoother.