turbo questions

[eckoxl]

As some may know or may not know, I have decided to turbo my grand am. I have been doing research, but I am still stumped on what size/kind turbo to get.

I have been looking at this turbo, with a tial wastegate at 9 psi. I want most of my setup to be v-band, just because, to me, it looks cleaner and easier to use.

Supporting mods will be 3500 heads, performance camshaft (int. 3118, ex. 3118, ICL. 113, LSA .112), ported intakes, comp cams springs, custom log style manifolds, gtp injectors, 2.5 exhaust.

Pretty much I'm just looking for recommendations, tips, anything really.

For goals, I don't really have any. Just a faster, funner car than I have. lol.

[3400beretta]

You don't really need the cam. Save some money. You will not see a benefit from it that is worth while at your power level. There are those on here that will not agree with that, but here is something to think about. You can get a buick grand national WELL into the 10 second 1/4 mile club without touching that cam, which by the way has less lift and less duration that a stock 3x00 cam.

For the turbo, go for at least a large t3/t4 hybrid. Stick with Garrett or other name brand (no ebay chinese junk). Spring for a GT35 if you have the money, although not necessary. Make sure whatever you get has a 360 degree thrust bearing. A full T4 is not necessary, again, but would all depend on when you want boost. I have a T3/T4 60-1, with a .82 A/R hot side, and I do not see full boost (11psi) until about 3200 rpms or so, on a 3500. If you have no idea what I just said, you need to do some research on compressor and turbine sizing. Maximum Boost by corky bell is a good book to start with. PM me if you want to talk about this more.

If you can, stay away from log manifolds. This right here, is much more important than a camshaft right now. Use the money you saved to have some header style manfiolds made up.

I assume you are keeping the car auto? That transmission (4t45) is not going to hold up very long to any sort of abuse. Look into having it built up, or swap to a 4t65hd from the grand prix gtp. This is a big problem you are going to have to address, sooner or later. Swapping transmissions is NOT going to be a simple job, I'm just giving you options.
Also consider getting an LSD unit from jeff at EP (http://www.engineered.net/).

You did not mention anything about intercoolers. Get yourself an intercooler. I bought mine from treadstone performance, they are spearco copies, and are just as good, at less than half the price. Vertical cores (with tanks on top and bottom) are more efficient than horizontal, but are more $$.

You are going to need a larger fuel pump. Watch out for fake walbro pumps being sold on ebay and elsewhere.

Whatever your budget is for this project, expect to spend double. There are so many things you are forgetting right now, that you will have to buy along the way. This is all I can think of right now. Good luck.

[Weatheralls Auto]

Much of what I have read (including here) says Headers for Turbo are really not needed?

I have been planning on making log style manifolds for my Turbo app (mainly room constrictions)

Edit add:
From Boosted section here

Exhaust for a turbo setup: Headers are a waste on a turbocharged engine unless a custom exhaust is needed for mounting the turbocharger. The use of headers for a turbocharged motor will not provide performance improvments as they do a normally aspirated motor. The reason for this is that headers work by using the scavanging effect, and once an obstruction to normal exhaust gas flow that a turbo represents has been attached, the scavanging effect is no longer available.

[eckoxl]

You don't really need the cam. Save some money. You will not see a benefit from it that is worth while at your power level. There are those on here that will not agree with that, but here is something to think about. You can get a buick grand national WELL into the 10 second 1/4 mile club without touching that cam, which by the way has less lift and less duration that a stock 3x00 cam.

Well, I've already bought the cam, so it's staying.

For the turbo, go for at least a large t3/t4 hybrid. Stick with Garrett or other name brand (no ebay chinese junk). Spring for a GT35 if you have the money, although not necessary. Make sure whatever you get has a 360 degree thrust bearing. A full T4 is not necessary, again, but would all depend on when you want boost. I have a T3/T4 60-1, with a .82 A/R hot side, and I do not see full boost (11psi) until about 3200 rpms or so, on a 3500. If you have no idea what I just said, you need to do some research on compressor and turbine sizing. Maximum Boost by corky bell is a good book to start with. PM me if you want to talk about this more.

I was actually looking at this one. (link)

I assume you are keeping the car auto? That transmission (4t45) is not going to hold up very long to any sort of abuse. Look into having it built up, or swap to a 4t65hd from the grand prix gtp. This is a big problem you are going to have to address, sooner or later. Swapping transmissions is NOT going to be a simple job, I'm just giving you options.
Also consider getting an LSD unit from jeff at EP (http://www.engineered.net/).

Already have a rebuilt 4t45 with upgraded parts

You did not mention anything about intercoolers. Get yourself an intercooler. I bought mine from treadstone performance, they are spearco copies, and are just as good, at less than half the price. Vertical cores (with tanks on top and bottom) are more efficient than horizontal, but are more $$.

Thats because I was leaving the real obvious stuff out.

Thanks for all the information.

[3400beretta]

Much of what I have read (including here) says Headers for Turbo are really not needed?

I have been planning on making log style manifolds for my Turbo app (mainly room constrictions)

Edit add:
From Boosted section here

That is 100% correct. True headers work on a scavaging effect, the previous cylinder helping to "suck" exhaust gasses out of the next. Obviously that will not work with a big turbo sitting downstream. However, most log style manifolds are extremely restrictive, vs an individual runner style manifold. I was assuming that you were going to modifiy stock log manifolds, which IMHO is a terrible idea. If you are building your own log style, try to make them as free flowing as possible. Or you can do what I did, get ahold of 2 3500 "front" header style manifolds, and do a custom crossover. The outlets point straight down, and they are *WAY* better than any log setup.

[3400beretta]

And a note on that turbo you are looking at. That is the chinese crap I'm referring to. Its up to you of course, but I would not touch anything like that with a 10 ft pole. They are made with inferior materials, and inferior workmanship. A total waste of money if you ask me.

If that was a real garrett turbo, it would be a good choice, except I would change the a/r on the turbine to .82. With a .63 a/r like that turbo has, it will spool really quick, but pose a restriction in the upper rpms. That is more for a big 4 cylinder or smaller v6. My guess is, that you would hit full boost (9 psi) at around 2200-2500 rpm with a .63 a/r. Again, totally up to you though, depends on what you want.

[robertisaar]

you know, my T70 knockoff(actually very close to a GT3776 in EVERY spec except for the exhaust minor diameter and possibly turbine A/R) shows good specs for a SP3100 trying to reach 410HP...

http://www.squirrelpf.com/turbocalc/index.php?version=4&target_peak_power=410&pr_ref=14.696&engine_disp=3.1&engine_disp_factor=0&target_af=11&bfsc=0.47&max_ic_loss=1.5&rpm_redline=6000&rpm_peak_power=5200&rpm_max_boost=4000&rpm_min_boost=3000&vol_1=87&vol_2=87&vol_3=85&vol_4=84&vol_1=87&vol_2=87&vol_3=85&vol_4=84&intake_temp_1=90&intake_temp_2=120&intake_temp_3=135&intake_temp_4=140&turbo_n=1&map_sel0=43

[Joseph Upson]

Check out the links I posted in this thread;

http://60degreev6.com/forum/f107/is-this-turbo-a-good-option-t45144

Although I hear the ebay turbos are much better than they use to be, after two buyers sold me a turbo that was not what they said it was, I decided not to fool around with them anymore in this area. If you get a great deal on a turbo that is too small for your application, it's still no help. The big problem I see with ebay turbos is that they carry names that they don't meet the specs for. Any "T" series turbo such as 66,67,70 or 76 should have an inducer blade diameter of that many milimeters or at least be close enough to be rounded to it. If not, it's not the turbo they're calling it and you may dump good money on something that falls short of your performance requirements like the two sellers I dealt with must have.

I checked and when the numbers didn't add up, it was dispute, return, and refund.

Get a water cooled housing if you can. Headers are not a requirement but they do offer an advantage over many if not most log style manifolds by design efficiency with individual tube contours that favor good exhaust passage to the turbo as opposed to coming out of a port and slamming into a wall and trying to go left and right. They are also lighter if your stockers are cast iron.

The stock cam will give you the best all around performance since it is already proven and tested with the engine, and if you build a good exhaust system you are sure to reap the benefits of an slightly extended rpm productive power range which a properly sized turbo will add.

Since you already have the cam no problem. What I have learned since my reground camshaft for my turbo motor is that I chose a cam for higher horsepower and rpm. The reason that was a bad idea is because I shifted my torque and hp range further to the right of the hypothetical power grid. I'm a 0-60 street light to street light driver and by the time the fun gets started it's time to hit the brakes. The stock cam would have been perfect providing better low end grunt and I could simply turn the boost up to get the power level I wanted. If you're not racing it then the stock cam is likely the best bet.

Cam upgrades are much better for naturally aspirated engines.

There is some bias against alcohol injection but it is catching on just like turbocharging. Doesn't matter that you have to increase boost or timing to take advantage of it. The fact that it makes it possible for you to make more power is enough. Look into dual nozzle pre and post turbo injection which has proven so effective it has allowed some to eliminate their intercooler because it was no longer necessary.

Have fun

[robertisaar]

The big problem I see with ebay turbos is that they carry names that they don't meet the specs for. Any "T" series turbo such as 66,67,70 or 76 should have an inducer blade diameter of that many milimeters or at least be close enough to be rounded to it. If not, it's not the turbo they're calling it and you may dump good money on something that falls short of your performance requirements like the two sellers I dealt with must have.

i was pleasantly surprised when my "T70" turned out to be a better fit than what was described, but i wouldn't expect that kind of mislabeling to work in my favor again. the seller i got it from actually has the correct measurements on the site now.

my "T70" worked out to be:

52.7mm 76.1mm intake 48 trim
58.3mm 73.8mm exhaust 62 trim

which i can use the GT3776 compressor map for since that works out to 55 and 76.2mm. the turbine on the other hand is 72.5 and 66.5mm it's close, but i REALLY need to check exhaust A/R. not sure if i should believe the seller's spec of .82 or not...

[Joseph Upson]

i was pleasantly surprised when my "T70" turned out to be a better fit than what was described, but i wouldn't expect that kind of mislabeling to work in my favor again. the seller i got it from actually has the correct measurements on the site now.

my "T70" worked out to be:

52.7mm 76.1mm intake 48 trim
58.3mm 73.8mm exhaust 62 trim

which i can use the GT3776 compressor map for since that works out to 55 and 76.2mm. the turbine on the other hand is 72.5 and 66.5mm it's close, but i REALLY need to check exhaust A/R. not sure if i should believe the seller's spec of .82 or not...

That's roughly a TO4E 46, your inducer is 52.7 mm vs. a true T70 2.72" (69.09mm) and exducer of 3.085" (78.36 mm). That didn't work in your favor unless I'm missing something.

Wheel specs: http://www.turbocharged.com/catalog/comp_wheels.html

I challenged one vendor on the specs stating they did not match what the title indicated. They said that's what their vendor told them. It's apparent they know they are mis-identifying (false advertising) but since a lot of buyers are not aware of what makes a particular turbo what it is, they never check to confirm. Some unsuspecting buyers find out too late and try to pass the turbo off on someone else as the same thing they purchased it as, hoping the buyer will not investigate to make sure.

[robertisaar]

T70 + 3100 is a bit much for what i had in mind. but it seemed like a deal, so worst case scenario, it could have been used for something else.

i guess that compressor wheel is actually damn close as well. it sucks that i can never find a exhaust wheel that matches though... the T4 O Trim is close, but i don't know if i could fit in the the housing without clearance issues... or if i measured it wrong, who knows, it's been almost 4 years now.

/hijack.

[Joseph Upson]

Ok, relative to the engine yes you're in good shape.

[carbon]

As far as the cam thing goes... there is a lot you can do with a cam with forced induction. The thing that you have to remember is that the whole point of using forced induction is to get more air/fuel in the combustion chamber to increase power... if you use a cam with a larger overlap and longer duration designed/required for N/A power you will be blowing a lot of the charge strait out the tail pipe. You need to use a cam that has been set up with forced induction in mind.

[Joseph Upson]

As far as the cam thing goes... there is a lot you can do with a cam with forced induction. The thing that you have to remember is that the whole point of using forced induction is to get more air/fuel in the combustion chamber to increase power... if you use a cam with a larger overlap and longer duration designed/required for N/A power you will be blowing a lot of the charge strait out the tail pipe. You need to use a cam that has been set up with forced induction in mind.

It's not that simple, that's why it's so controversial. You can have all the overlap in the world and if it's combined with a restrictive exhaust system it can do just the opposite blowing exhaust gases back into the intake. It's a balance between boost pressure and exhaust back pressure not just overlap alone so a cam with overlap is not necessarily a bad choice. Low to no overlap is however a safety when you don't have the tech know how and flow dynamics for your build.

[Weatheralls Auto]

So you are saying, having a nice lumpy idling cam and turbo counter acts each other?

I know this is dumb, but I was thinking about changing cam, but just because I wanted and like the sound if a lumpy idle.

If that defeats the purpose having Turbo, I am glad I never ordered one and will completely forget about it now (and use that $ for something else lol )