Friend has an 87 TII , 190k on chassis , 60k-ish on the engine , stock ports.

Stock turbo started burning oil upon purchase of car. He pulled it off and it just puked oil all over the place so the seals are diffenetly shot.

Well he had some money saved up and decided to play the go big or go home stategy. He purchased a Garret Gt 40 from ebay , its basically new , he paid 400ish for it , it has an AR of I think .96 is that fine or did he go too big?

We did all the basic maintenance to it:

New plugs
wires
fuel filter
oil change
mazdaspeed motor mounts
koyo rad

Thing he purchased so far:
Walbro 255
Garret Gt40 .96 Ar
Microtech LT8
Hks 42mm(I think its 42mm) WG , 5lb spring
HKS mani
SSautocrap 3in turboback

He still needs:
1600ccs for the secondaries , should he keep the stock 550 primaries or go bigger?
Oil Lines = what size should they be AN wise , what about the restictor
I think he is going to get an HKS cai.


He's leaving the clutch stock for now thus the 5lb spring. Boost will be upped after new clutch is in and he actually has something bigger than the stock 16s that are on it to put it to the ground.


Anyway other than a new clutch what else is he missing to have a reliable 300-350whp since it is his daily driver?

Thanks in advance

 

It should produce very low numbers such as your goal at that level boost. GT series turbos like high boost numbers to be in their efficency

 

The wastegate is too small.


-Ted

 

Uh, where exactly does he say what PSI he will be running? 5lb wastegate spring does NOT = 5psi max. Try again..

Yeah, go with a big dog wastegate. 60mm anyone?

 

if he paid 400 for a gt40 then it's not going to last long cause for some odd reason dispite all the threads preaching against ssautocrap turbos people still insist on getting them.

edit: also the guy about the psi thing is right. A rule of thumb with wastegate springs and boost is 2xthe wastegate spring is the max boost and so that is 10psi witch is also not much at all! But try again.

 

Despite the wastegate, isn't a GT40 overkill on stock ports!? 350HP on a stock block is pretty high? No?

 

Yes, that's not exactly an ideal turbo choice for the goals.

 

Hmm so the 5 psi spring will actually produce 10psi? Anyone care to explain to me why that is , technically speaking?

Also the GT40 is a real Garret not some ebay ssautocrap knockoff. Its actually a truck turbo I think. Two of my friends have other GT40s and they bought theirs new for 700 so this seemed like a good deal at the time thus the purchase of it.
I am aware that it wont be efficient at low psi but the whole reason for it so to have the ability to upgrade down the line.

Is there anything else thats missing that I havent covered?

Also the car runs great now thus the stock ports, when it goes kaboom it will definetly be streetported thus the Gt40 should have some use.

Lastly wastegate size , whats the smallest one that will do the job and if one was trying to save some money which ones should he consider?

Thanks again.

 

that gt 40 cant be too much bigger then my mp t-70 on a stock port s4 motor. There is lag but boy ohh boy is there power. lol

im thinking of going with a smaller hot side a/r. right now its a 1.0 and i get full boost late... at about 4.5k or so.

that turbo should still make ~400whp at 15psi...

ohh and i have a 50mm WG.

dunno if any of that helps or not... hope so.

 

The 5psi spring will produce 5psi of positive manifold pressure if you do not raise it with a boost controller. A boost controller allows you safely to double whatever pressure the spring is rated for.

People are so easy to jump on others with low post counts on this board...Discouraging. He did not list a boost controller in his list nor is the lt8 capable of boost control (might be wrong here). Is it not possible to correct/add onto what someone has said without being insulting? Are there any other boards that are decent?...

 

your right the lt8 can not control boost.

 

dude, a GT40 turbo is way to big. This is a turbo designed for for somthing like 600hp, or at least upper 500's. I dont think its going to spool well on a stock port.

 

Thanks a lot for the info.

Boost controller will be added to the list.

 

One of the main reasons he chose to go GT40 was the price and the headroom that came with it. It wasnt just a blind decesion, I personally dont know enough on the subject or care to know enough because I am not at that stage of my project yet but I have two other friends who use GT40s for their custom turbo setups on other cars and by using compressor maps, the conclusion that they came upon is the Gt40 maybe be a bit laggy but it should be alright, as in full spool should be I think 4000-4500 which isnt too bad.

 

Doesn't a stock port have a limit to what amount of HP it can produce?

 

carlbyck made over 500 on stock ports. thats plenty.

 

No ****? That's awesome..

 

I'm not turbo expert either, but the car might be like this:

1000rpm; nothing, 2000rpm; nothing, 3000rpm; nothing, 4000rpm; nothing, 5000rpm; nothing, 6000 starting to boost, 7000 near engine blowing insanity then redline. I guess you could tone down the big surge with a boost controller.

But i dont really know, try it and let us know what happens!

 

I'm just curious to see if this is actually a gt40r or not.......Its a 2000 dollar turbo new! Any pics?

http://www.atpturbo.com/root/maps/gt40r.htm

That level of boost might not work to well for you, turbo surge what?

 

yeah, i was about to say. If it is a real GT40 turbo, thats a great deal. I have heard there is chinese copys out there, i wonder if its one of those.

 

Another thing, a lot of those ebay turbos arnt what they say at all. They also make outragous claims like " this gt28rs turbo can make over 600hp!!!!" I think the gt28rs is the OEM turbo on the nissan SR20det engine and good for about 350hp...

You said this GT40 you got has an A/R of .96? You better check that again because garrett doesnt make a GT40 with a .96 A/R

 

gt40r
Turbine
-Wheel: 77mm w/ 78trim
-Housing: .95 ar, 1.06 ar

Compressor
-Wheel: 88mm w/ 52 trim
-Housing: .58 ar


The gt28r has the same wheels that the t28 off of the s15 Silvia whatever edition had on it. Different from the gt28rs. The 28rs is also a good 300-500 dollars more then the 28r depending where ya get it from. The 28r produces a much better torque curve as well and maxes out only 20whp less then the 28rs' capabilities
gt28r>gt28rs. Dont buy the hype Sport Compact Car throws out there
gt28rs
Turbine
-Wheel: 53.85mm w/ 76 trim
-Housing: .64 or .86 ar

Compressor
-Wheel: 60mm w/ 62 trim
-Housing: .60 ar

gt28r
Turbine
-Wheel: 53mm w/ 62 trim
-Housing: .64 ar

Compressor
-Wheel: 60mm w/ 60 trim
-Housing: .60 ar

 

GT40R is not the same as the GT40..The GT40 lacks ball-bearing, so it would probably have different specs. (Like GT35 vs GT35R)

 

thats IF the apex seals dont go through it.

 

The GT40 is a non-ball bearing good for about 425-450. Think of it as a non-ball bearing GT35R (same cold side).

Pretty much the same as the Blowzilla.