Garrett .42/48 for 4.0

4.0 Turbonetics t62 discussion

what do you guys think? too small? just right?

looking for 5-6 psi out of it. should spool up super fast thats for sure, esp with my 10:1 compression ratio. i have a chance to get this turbo for $45. yay? or nay?
No longer going to run the tiny turbo, so discussion will change to this t62 .63/.48 turbo

 

[jd4242]

So what would be best?witch would be more efficient and easyer on the motor?

 

[fishy2k8]

well the advantage of the higher compression in a turbo application would be faster spool times. other than that.. i'd just google turbo info cause im not really sure on the pros/cons to compression lol

a lot of it has to do with final compression ratio vs octane and intake temps

basically, on a 8:1 compression motor with 14 psi boost you can run is about 15.6:1 [((boost psi / 14.7) + 1) x motor compression = effective compression] compression on 93 octane with a decent timing curve. a 15:1 static compression motor would not run well on 93 octane and would not be a very nice daily driver either.

now, on 10:1 compression, to get the same 15.6:1 final compression you'd only need to run about 8 psi. with the high cr, you'll get better low end torque and quick spools and run less boost

as far as which is better, depends on what your goals are and how it will be driven

 

[Jakee]

Good discussion!

I've seen a LOT of builds where people would drop the compression ratio of the piston, dump tons of money on forged stuff, then be unsatisfied because, like Rocket said, they lose the throttle response. The vehicle seems “laggy”. This is pretty significant for a street vehicle. It's no fun to have to floor the darn thing to get somewhere (built motor with low compression pistons), compared to just a little throttle to get the same effect (stock motor with stock compression (higher)). Most that have experienced this dreadful situation has quit. (Also consider the weight of the new parts compared to stock. This makes a difference on the way the motor revs) They dumped tons of money and didn’t get the results they were looking for. They start to think, “why the hell did I do all this; spend all this money on this motor and the boosted stock set-up seemed better. Screw this, I’m done…”

An all out race car is different. Who cares if you have to floor it, that's what it's built for..there's no farting around with the throttle; it's either floored or not.

And this is why the higher compression motors with lower boost settings is the idle street application. And that effective compression ratio formula is good. From what I read, you don’t want to go over 18 to 19 if you’re planning a build.

And thank goodness for knock sensors with these 4.0 SOCH motors..it adds a safety factor with the tune...I mean, you can tune the crap out of the motor and it seems as things change after awhile. It surprises me when I log things to see changes....The load, temperature, octane…etc…I'm constantly making adjustments in the tune.

 

[fishy2k8]

lets just say, i watched and help a friend of mine build his turbo ranger (built 2.3 with expensive forged pistons and rods, 8:1 compression, fairly large turbo, ect) and when all said and done, he was running 285 rwhp on 14 psi boost... now, it could have handled a lot more, but being something he wanted to daily (and blowing 2 head gaskets on his first turbo setup, he kept it conservative. the thing is, the turbo spooled real late and didn't make full boost until like low 4000 rpms. for ripping around on the street that sucks, but damn once the boost hit it was fun!. anyways, after awhile he was tired of it because of the oil blow by he was having and was just plain done messing with it and was done dumping money into it.

anyways, if he hadn't spent a ton of money on pistons (just ran stock forged pistons out of a turbo coupe) and ran a bit of a smaller turbo, i think he would have enjoyed the truck a lot more and wouldn't have sold it (for a too cheap of a price at that).

as far as the knock sensor.. i wish the ohv motors had one! but, since they dont, i did find this pretty cool autometer iat gauge that comes with 2 probes to put in the charge tubes and lets u see the iat's the motor is getting, u can see before and after ic too. pretty cool, and will help keep an eye on the temps on a real hot day, ect. with that a wideband and fuel pressure (which i already have) ill be golden on keeping a safe eye on the motor vitals.

 

[jd4242]

well the advantage of the higher compression in a turbo application would be faster spool times. other than that.. i'd just google turbo info cause im not really sure on the pros/cons to compression lol

a lot of it has to do with final compression ratio vs octane and intake temps

basically, on a 8:1 compression motor with 14 psi boost you can run is about 15.6:1 [((boost psi / 14.7) + 1) x motor compression = effective compression] compression on 93 octane with a decent timing curve. a 15:1 static compression motor would not run well on 93 octane and would not be a very nice daily driver either.

now, on 10:1 compression, to get the same 15.6:1 final compression you'd only need to run about 8 psi. with the high cr, you'll get better low end torque and quick spools and run less boost

as far as which is better, depends on what your goals are and how it will be driven

Wow thats a big difference in boost.good info!

 

[fishy2k8]

with the 5-6#'s i plan to run, my effective compression will be around 14:1 at max boost

 

[jd4242]

How much power do you think it will add?

 

[fishy2k8]

not really sure, i dont have any expectations for it honestly, i just want a cool setup that works good, is safe. with that, ill make plenty of honest power... just remember - there's always someone faster haha

 

[fishy2k8]

Those who have does 4.0 turbo setups and are reading this thread, please post your hot side setups. I'm debating whether to try a hotside in front of the motor or do like others and run it behind the motor. Need to look at it more, but I think it's gunna be a pretty tight with with my headers there too.

Should I keep the turbo exhaust feed the same size as the connecting piece between each side? I'm sure I'll come up with a trick way to fab it up, just cloud thinking right now until I actually start cutting stuff up so I have some idea of what I want.

 

[Jakee]

If you mount behind the motor, you'll more than likely need an oil return pump. If you mount in the engine compartment and above the oil pan, you can use gravity. I'm sure you know this but this is what I would be thinking mostly about at this point in the build.

I've ran into problems with my scavenge pump, but it was mostly my fault (un-plug it and forget to plug it back...etc) But it is a major pain to clean all the oil out of the intercooler if this happens.

I would try and fit in the engine compartment somewhere. If it's just not possible, then find the closest place to the engine you can get. If you want major turbo sound coming from the exhaust then you could mount way in the back past the muffler. It's up to you, I personally like front mounts myself. Just can't beat em..And no oil scavenge pump would be cheaper.

Keep the exhaust feed the same size as the turbo exhaust inlet. The restriction needed to make boost is built into exhaust housing so you don't need to be smaller. And any bigger is probably not going to help any.

 

[Jakee]

If you can, make the merge happen as close to the turbo exhaust inlet as possible. This will help spool (you don't need it now LOL) but later this is optimal.

The wastegate inlet is best to be in-line with the inlet flow. (instead of a 90 degree into the wastegate, try for a direct shot) same with the wastegate outlet pipe when re-entering the exhaust.

 

[Jakee]

-4AN line for the turbo oil feed
-10 to -12AN line for the turbo drain (when using gravity)
-6 for the turbo oil drain when using a scavenge pump


The MAF pipe, like Rocket said, is important to be straight and free of anything that may cause turbulance on the MAF meter. Turbulance makes tuning a nightmare and you'll never get it tuned correctly.

 

[Jakee]

Sorry for being a MAJOR thread hogger here...hehe

I believe the average is 15 HP per pound of boost. So 15 * 5 = 75 HP (this is just a guestimate) Some SU's lower, some higher.

I'm done, the end

 

[fishy2k8]

I'll read all this later! Haha but, I was more so referring to running the exhaust side side connector in the back of motor or front. Not the turbo, that'll def be going on the engine bay.

I got a 1/2" -8 fitting for return, I read that is sufficient, no? It's going in the timjn cover and I have limited room.

.. yeah ill make sure the maf has no turbulence issues

not sure what you mean by 90 degree for the wastegate, was probably just going to mount the flange right to the turbo feed if i can, depends on where the placement of the turbo ends up. with the a/c there i feel like it's going to be super tight... could always toss a/c, but i'd rather keep it.

 

[Jakee]

It'll probably work. The trick is to have the oil flowing out of the turbo, the same, or faster than what is going in.

 

[fishy2k8]

maybe a -3 for feed instead of a -4? shouldn't really matter cause im going to use an oil restrictor anyways

 

[fishy2k8]

got the turbo today. it's super dirty but ill post up some pics after i clean it off. it's got factory stampings on it ill post up as well. gotta figure out if the wastegate can be bypass or not so i can run an external with a lighter spring

 

[fishy2k8]

the only thing i could really make out was the a/r .48 a/r .42 and IDM 5365

 

[rocket 5979]

maybe a -3 for feed instead of a -4? shouldn't really matter cause im going to use an oil restrictor anyways

Keep it a -4 feed. It is much easier to find -4 fittings than -3 stuff since -3 stuff is usually only used for the nitrous nozzle/jet side of the nitrous/fuel lines leading from the solenoids to the nozzle. I cannot think of anywhere else -3 is commonly used besides that.

 

[fishy2k8]

ahh good to know, will do