Ok i have been planning an engine swap to a L67/32 and 4t65e since spring... with the plan to come together around spring or summer next year. i have now given plenty of thought to it all have are going in new direction.

instead of the 3800. i am going to keep the LQ1. i have a friend who has successfully swapped to a 97 LQ1 pcm harness and trany, so i will have access to help trouble shooting if i need it. So here is the plan... my questions will come shortly....

Stage 1:
- use the money i saved to buy a perf built trany that can handle 350-400 hp
-modify or buy 97 lq1 harness and PCM
-Use my current engine and push tuning now that the 4t60 wont be limiting its power

Stage 2:
-buy another Lq1 and rebuild it for a Turbo.
-break out the TI-85 and begin my number crunching. pick a perfect CR for the turbo
-Dust off the plans for my custom intake manifold!!! with intake manifolds long runners help make low end and short help top end. same thing with volume of the intake manifold.. the larger the volume the more top end and smaller the more lower end. Using all of this, i hope to build a Turbo manifold that will give me the widest power band i can have.

So....Here is my question/ info i ad looking for. I am reading thru that book Maximum Boost again but it has been some time since i last read it. does anyone know off hand a way to pic CR for a turbo i know most people go with a t3/t4 hybrid for these cars... but i really want to know why... don't want to do something just cause everyone else did it.

also i'm thinking about using one of the cheaper ebay turbos that are designed for like 12-15 psi and running them at 5-6 psi i would rather not run an inter-cooler, but if i do, I may up the boost to 9 psi. of course KR and tuning will be considered as i fine tune the boost.

Help and suggestions are welcome!

 

Good luck man, this should be interesting to see what could come from it.

 

be sure to update us with this, should be awesome!

 

heck yeah. this should be VERY interesting this is gonna be one wild z34

 

Do you mean AR for the turbo? I was thinking CR = compression ratio of the engine since you were talking about a rebuild above- but I'm thinking you may mean AR?

IMO, I wouldn't. You get what you pay for, and close tolerance stuff spinning crazy RPM isn't a great place to skimp. Sure it can't do a ton of damage when it goes bad, but I still don't see the point in putting all the fab time into it, just to short change yourself with a cheap knockoff turbo. I'm sure they're not all bad, but I've just seen 2 locals (one here, one back at home)- and both had problems in abnormally short periods of time (shaft play, oil leakage, etc).

Any reason why you don't? IMO, not running an A2A IC on a turbo is leaving a nice bit of easy/relatively cheap power on the table. I can understand if you're just wanting to skip it now to keep in budget or something- but I'd definitely plan to add one long term. If you're wanting to keep it under a certain power level, you could always back the boost down until you go to the track or want to do a serious race.

 

I see your point about the a2a intercooler. I just wan to minimize the install. But yeah it's worth doing. Turbo is prob the last part of my project anyway. Trany, rebuild engine, then turbo. Thanks for the I site. Will keep all informed

 

Sure it can. I've seen plenty of centrifugal compressors (turbo and centri blower) cause engine failure. When the compressor decides to eat itself, all of those metal shavings find their way into the engine oil and catastrophic bearing failure usually results.

If your compressor is self lubricating, it might be worth gambling on, but if it uses engine oil, no way.

You'll definitely want some means of cooling the charge. Believe me- I'm currently running a non-cooled centri compressor on my Mustang. It traps 92 MPH in the 1/8 mile and is an absolute beast down low, but once the IATs heat up it dies (relatively) on the back half of the track and only manages to pick up another 21 MPH. bleh

Look into meth injection- it's super cheap and easy to setup. You'd want to configure your tune to pull timing once IATs rise past a certain threshold in case it fails, of course. I've got one coming in this week, as a matter of fact.

 

This should be pretty cool

 

keep us up-to-date on all your car projects

 

as for a cheep turbo, low boost wont kill it as fast as 10-15+ psi. im not one of the ricers that are going to crank up the boost and blow it up. i have done some research and seen that most of the bad results are with people who didn't spend the time to break in the turbo. some of the ebay turbos even say they aren't for daily driving! but some are. also it only makes sense to run an additional filter on the return oil from the turbo.

who knows by the time i get far enough along i may have he extra cash to spend on a better turbo but my current budget just doesn't call for it.


as for the inter cooler... i just might put one on. Meth injection is just asking for problems. it is fine for the track but not on a DD. yes you can tweak your bin to make it slightly safer but when the pump dies or stops spraying there will be a delay before the IAT's catch up and by then the damage is done