looking for parts

[SE7EN]

I am looking for some aftermarket internals before i think about installing a turbo i just not sure were to look for them.

can someone tell me were to look for some aftermarket parts for a 91 XLT 4.0 5speed.

I am looking for, please let me know were i can find any of these please.

Cam- bigger then stock, "what is stock duration & lift?"

Pistons- is stock size good for turbo 9.3:1 or is there anything lower and or a little bit bigger .020 or .030

Valves- is there anything to upgrade here?

Valve springs- is there anything stiffer that can handle a little more rpms with turbo?

Crank- is there anything to upgrade on this?

Headers- i plan on adding a turbo so i dont want to buy them if i wont need them.

 

[Donner]

Yo! How ya doin'? These parts and items, are you looking for new, used; online purchases, etc... and have you looked through the For Sale Forum? Also, search Turbo, and you'll find some builds that might help you out...

 

[Cobraguy]

turbo=pressure. That means you should upgrade your internals to forged where possible. Now, the 4.0 is pretty good as is. But if I were building an engine for a supercharger or turbo (and I've built a few) I would first determine my boost requirements and go from there. Your turbo supplier will be a wealth of information. Build an engine with forged pistons and lower compression. Move the top ring land down on the piston if you can find one. Leave the piston clearance on the loose side. Camshaft selection isn't as critical on boosted applications as na apps. But you do NOT want to go too big on a turbo. You'll never get the thing spooled up and it will be a pig to drive around town. Use good bottom end components and be meticulous in your assembly. Finally, talk to turbo guys. A lot. Find out what they did wrong, right, and what they wish they had done. Do your research and find a good supplier. There are some pretty shady ones out there. The good ones will have a good rep among the turbo boys. Also, go with an intercooler if possible. You won't be sorry.

I've just touched on the surface of this subject. I could write for a couple of hours just on the piston selection process. I highly recommend books written by Richard Holdener. He's done more research on boosted Ford's than anyone I know.

 

[SE7EN]

turbo=pressure. That means you should upgrade your internals to forged where possible. Now, the 4.0 is pretty good as is. But if I were building an engine for a supercharger or turbo (and I've built a few) I would first determine my boost requirements and go from there. Your turbo supplier will be a wealth of information. Build an engine with forged pistons and lower compression. Move the top ring land down on the piston if you can find one. Leave the piston clearance on the loose side. Camshaft selection isn't as critical on boosted applications as na apps. But you do NOT want to go too big on a turbo. You'll never get the thing spooled up and it will be a pig to drive around town. Use good bottom end components and be meticulous in your assembly. Finally, talk to turbo guys. A lot. Find out what they did wrong, right, and what they wish they had done. Do your research and find a good supplier. There are some pretty shady ones out there. The good ones will have a good rep among the turbo boys. Also, go with an intercooler if possible. You won't be sorry.

I've just touched on the surface of this subject. I could write for a couple of hours just on the piston selection process. I highly recommend books written by Richard Holdener. He's done more research on boosted Ford's than anyone I know.

yea i was going to buy another cavalier and turbo it so i have done plenty of research on what i would need for a turbo such as forged pistons, lower compresion, but im not sure if they make a lower compression piston for a 91 4.0 do they? i cant find any but maybe im loking in all the wrong places.

i believe the stock Compression on a 91 4.0 is a 9.3:1 right? do they make anything lower?

this is why i am asking were i can find the parts i need and since i dont need a different crank i wont worry about it. b ut any idea's were i could find parts i need?

also i will find a way to be using an intercooler.

i have never heard of moving the top ring on a piston land down?

before i forget what is the stock cam specs, i found these specs on a cam at autopartswarehouse

"Duration 270 Intake/284 Exhaust, Valve Lift 0.500 Intake/0.500 Exhaust, 112 Degrees Lobe Angle"

is that what stock is or is this bigger then stock?

 

[Cobraguy]

Piston manufacturers will move the ring package (and therefore the top ring) down on the piston in boosted applications if they have the room. This makes the engine much less prone to detonation. Vehicle manufacturers try and bring the top ring up because it makes the engine run cleaner. But that can enhance detonation. Not good on a boosted motor. So if you end up ordering pistons, ask them about that. As to lower compression pistons, if they aren't available, you have two choices. (1) machine a set if there is enough material (doubtful) or (2) order a set custom made. (expensive...but a lot of guys do it) Otherwise, just run the stock compression and limit your boost. That will probably be more than sufficient for you anyway. But an 8.5:1 motor with the right ring package would sure make for a fun application!

 

[turbo cat]

I still havent broken my motor yet. full 92 oem longblock with unknown miles (yard motor) no tuned just tricked and ive pushed my little gauge to over 15psi. The weak link so far is the headgaskets and or cracking heads. Ill have more info on which is the case whend i finally pull it apart. 9.3:1 is fine any lower and spool time will suffer. The 4.0 is a torque motor not an all out HP motor thsi is why I have a very small turbo that can spool before peak torque. Dont go too big on the turbo youll regret it. As for the cam save your money as a bigger cam will eat your gas money, kill spool time and cause reversion problems up high. The main focus for big boost is NEW cylinder heads (ones that woulnt crack) good headgaskets and a fuel system up to the task and the tuning for the ecu to keep everything alive (I dont even have tuning for my truck yet and still havent broken the motor) when i bought the truck is had a blown HG and going up a hill it lost all the water, overheated and started the death rattle...detonation so bad that it blew the HG out everywhere, cracked the heads all over the place and broke the valves but the pistons were good to go. this is before i knew how strong the 4.0s and i got to find out with first hand experience how strong the bottom end is. The crank is forged along with the rods. if you want t oyou could upgrade the hardware to ARp stuff to put some insurrance on the bottom end

 

[SE7EN]

wow thank you, you just saved me money, lol (that just reminded me of the insurance commercials).

do you have any turbos in mind that arent to big, i went to this website and found this turbo http://www.cheapturbo.com and here is the spec of the turbo i found

$619.00

Product Description
COMPRESSOR SPECS:
flow: 46lbs/min 588cfm
50 TRIM WHEEL
TURBINE SPECS:
.48 A/R HOUSING
STAGE 3 WHEEL
oil lubricated centersection.
supportable of 400whp!


any other ideas, or what specs should i be looking for? i may be able to order it through my work instead of ordering off the internet. i want one with an external wastegate

how about this one
http://www.turbochargers.com/store/product_info.php/cPath/21_37_222/products_id/1581

 

[turbo cat]

Stay away from the ebay/chinajunk turbos. They can come apart, have bad casting flaws, not balanced....i pulled mine off of a 80s chrysler 2.5L turbo. Its a 50 trim garret(formally airesearch) T3 with a .48AR exhaust housing. I bought it for 16$. If you want a nice fancy new turbo you may look into master power turbos.There a brazilian made garret knock off that sells for half the price with the same quality of a garret.if i were you I would snatc hup a Tbird Turbocoupe T3 with a .68ARhousing