: big turbo vs little turbo.
06-07-2010, 04:07 PM
Okay, just trying to think outloud here.
So Big turbo vs small turbo power.
assuming 1 psi is equal to 10 hp or so would this be the same for big and small turbos. just at different rpm?
eg : -small turbo 10 psi.
-zetec 130 stock
- 230 crank hp ? with power dropping off at 6k or so?
eg 2: - big turbo 10 psi
-zetec 130 hp stock
- WOuld this still me 230 crank hp? but bring power through till redline?
The only thing im confused on is if 10 psi from the small turbo is going to make the same hp as the 10 psi on the bigger turbo.
06-07-2010, 04:21 PM
Your very close with your thinking , A small turbo will spool up faster vs slower with a big turbo , I am not a big fan of a fast spooling turbo , its a combination that your looking for and many things need to be looked at
small = 10psi
Big = 10-12 psi
Again all depends on thee combination and the turbo
06-07-2010, 04:23 PM
okay, So if i were to run 12 psi with any turbo on my stock zetec, It should put me right around 250 crank hp?
06-07-2010, 04:46 PM
Or in my case my bigger turbo is making 13.75 whp per psi
06-07-2010, 04:48 PM
He has a stock engine and doesnt need a turbo for 500hp so wouldnt need to go that big
06-07-2010, 05:11 PM
Sadly i have a turbo that will support 500 crank hp, But after my 42/48 turbo i always told myself im going alot bigger. because on my poor flowing 1.9 escort i was running out of turbo at about 4800 rpm. with the better flowing zetec i want a stong turbo that would pull to redline. Im willing to comprimise a little bit of lag.
its a t3/t4 54 trim with .63 exh side. Go big or go home :) [woot]
06-07-2010, 07:05 PM
doubt a 54/63 will get you to 400 let alone 500 , thats why it was falling off on the top doubt it can move enough air to maintain higher rpm boost
06-07-2010, 07:45 PM
so what do you think i can expect out of my garrett t3/t4 57 trim? its a .60 A/R on the compressor and a .63 in the hot side. and I plan on trying to rebuild it myself but I want to have it sent of for balancing cause I dont wanna risk it.
06-07-2010, 07:49 PM
57 trim is good to about 400whp. Tim (Turbo Turtle) got a 50 trim to 353whp (with the Roush manifold).
06-07-2010, 07:59 PM
i know your going to hate me because its SPA but this is what i have
Suggested application: 1.6L - 2.5L engines
Turbine Housing: free float
Single:A/R .36, A/R .48, A/R .63 / T3 flange with a 4-bolt downpipe flange
Compressor Housing: A/R .50 please see technical drawing
Notes: good up to 500 HP
Average weight: 9.0 Kg / 19.73 lbs
Turbine TRIM: 73
06-07-2010, 08:54 PM
In most cases take off 100HP from rated , I lean more to the 130 range with the off brand turbos so you should be able to get 370+/-HP
06-07-2010, 09:06 PM
Yeah, my biggest concern was an upper range powerband, I didnt want power to drop off after 4500-5000 rpm. When i build the engine, I may swap turbos for something a bit smaller. This turbo barely fits. It had to be clocked up so it wouldnt hit the crank sensor ( i believe thats the one pointing to the flywheel on the front of the tranny )
06-07-2010, 09:44 PM
Yep, crank sensor. With my setup, it comes verrrry close.
If you're running the SPA manifold, that's the main reason. My manifold puts the turbo out a little further.
06-07-2010, 10:49 PM
Also keep in mind that your hot side AR plays a very important part in your performance.
A smaller AR will spool faster but will become a bottle neck at higher power, a larger AR (for example my .86ar on my GT28rs) will spool a little slower but it will flow amazingly up top.
06-08-2010, 07:46 AM
It all depends on what you want for driveability also. If you want a track car that pulls to 7200 it will not be as much fun on the street. If you are into more street fun you want something at full boost and torque quickly. Nothing improves driveability like 350 + ft-lbs at 3000rpm or less. :)
I will admit I am not as familiar with the flow characteristics of these little motors. Boost pressure is a result of how much flow the motor/heads/exhaust can handle.
A good electronic boost controller helps also. I am using an E-boost II on the marauder and the adjustability keeps boost from dropping off at high rpms. I am getting about 22 hp per 1 psi of boost now. I expect to get every available molecule out of the 66mm up to 6500 rpm with the E-Boost when I get off my lazy-azz and put the forged motor in.
06-08-2010, 10:22 AM
a 50 trim will easily hit 400whp.. i had that exact same turbo and didnt like the fact it took so long to boost.. i mean dont get me wrong but i never took my car all the way to 7200rpm so i changed the hot side to a .48 and now it spools almost instantly and put down over 400whp.. and its crazy fun on the street too..lol..
06-08-2010, 10:49 AM
I also have a .48 spare hotside if i ever want to swap it out.