couple t25 questions

We may earn a small commission from affiliate links and paid advertisements. Terms

Matts96HB

.
Moderator
VIP
I bought a T25 from a guy for 120 shipped. I knew it was going to need some work, I'm starting by replacing the wastegate. It has some shaft play, and there are some marks where the fins hit the housing. It was recently rebuilt, so I'm not sure if the marks were from before the rebuild, or after. It doesnt seem to be touching now. My question is, how much shaft play is acceptable? And if its too much, what needs to be replaced to fix it?

Another question: cooling. Do I need to run coolant/water through this as well? If so where should it come from?

Any help is appreciated.. thanks..
 
there should be a place to run oil to and from the turbo...some are water cooled as well; those have a place to run coolant to and from them along with oil, but I've never dealt with a water cooled turbo so ask an expert. what kind of turbo is it?
 
Last edited:
ALL turbos have shaft play. it is just a bearing device afterall. it should spin freely and not wobble, but it will move a mm with your force.

if the turbo was meant for water cooling, its best to water cool it.
water lines are best/easiest to tap from up by the throttle body. just make sure you have a good loop with easy returns, and no air pockets.
 
Turbo's when you shut them down coke, which is the oil burning due to no flow, water cooling helps control the over temp issue and adds life.
 
For the money you spent on that why did you not just get an ebay turbo? even if the turbo is a POS and will only last a year you could at least match it correctly to your engine. A T25 is just about large enough for my lawn mower. Yes you can over boost them to 10 psi but the eff drops way off and all you get is hot air with more change for detonation. If you are running the normal 1.6 -1.8 honda engine you should be looking at a T3/T4 57 trim turbo.
 
And how does it not match my engine? For my power goals, its a decent turbo. This is a thread asking questions about a turbo I have already bought, so I really dont need your comments unless they are helpful.
 
I'm not trying to flame you about the turbo, but with you goal of 250 whp I think you will have difficulty meeting your goal with that small of a turbo. The turbo will be off the compressor map prior to max torque, and out of air on the top end, but it will spool right off of idle so thats in its favor. I would suggest you go to Ray Hall Turbocharging - Java turbocharger flow map calculator and compare your turbo and a correctly matched turbo and see the differences between the two. I have used T25 turbo's and after swapping the turbo to a larger one I gained roughly 50 whp at the same boost level due to increased efficiency. And yes ebay turbo's can and are pos but I have been running two cars with ebay turbo's with zero problems for over a year, each turbo was roughly $145. but its your choice of course, I'm just trying to give you a suggestion to save you some problems that I ran into as in bad turbo matching to engine.
 
I have used T25 turbo's and after swapping the turbo to a larger one I gained roughly 50 whp at the same boost level

captain ovbious.gif

due to increased efficiency.
not necessarily true.

efficiency doesn't mean it makes more power. simply put, a bigger turbo will 99% of the time make more power than a smaller one (assuming of course, we are in limits of motors and such... you get my point)
 
Pissedoffsol, I should have been more careful in how I phrased my comment, the larger turbo due to its larger size and "pumping efficiency" will be more effective in moving air then the smaller turbo. I will know that this issue is a dead horse as in topic so I was giving a short answer.
 
I understand that I probably wont hit 250whp with this turbo. I know I will probably be upgrading, which is fine with me. I want this to be something to learn from right now, I figure a small turbo is a good starting point. Plus, the gears are so damn short, dont I want something that is going to spool quick? Its a b16 tranny. 4k @ 70 mph
 
Good planning as to "starter turbo" and such. Something to think about also is the mounting flange, if you run a T25 you will need another manifold when you are ready to upgrade, if you use a T3 you will have a lot more options for turbo's that is. How I look at it now is if possible I try to have an upgrade path for the future as in reusing manifolds and such.
 
b16 tranny on an ls motor FTL. lol

Well, yeah for all motor it would have been good but for boost i think id rather have a gsr or ls with an after market lsd on it. But, this is what ive got, so I'm kinda stuck with it.

As for the planning. The only reason I stuck with the t25 is because ill be driving this for spring and summer then I'm off to college so this will see minimal driving during the times im away at college. Then when I get out ill buy a DD and have this as a project.
 
I have used T25 turbo's and after swapping the turbo to a larger one I gained roughly 50 whp at the same boost level due to increased efficiency.
If you were running a DSM T25 that's most likely because it's holding boost longer. What you're describing would only be accomplished by a bigger turbine wheel.
 
Thanks for all the responses guys.

I have more questions. Here we go. Im having a massive branfart right now. Cant remember what I need to buy.

Here's what I have so far:
Garrett T25
Boost, Oil Pressure, Air/Fuel Gauges
Greddy RS BOV
Manifold (On the way)
Ext. Wastegate (on the way)
3" Downpipe (getting from a friend)

As far as I know, I need:
Intercooler
Charge piping
Oil Feed/Return lines for the turbo
Injectors/Fuel pump for ~220-230 whp
and
Fuel management. As far as fuel management, what would you guys recommend? This is an obd2 car, with an obd2 ecu. What would be a solid way to tune this setup?

Again, any help is greatly appreciated
 
convert to an obd1 ecu and run crome if you wanna do it cheap, neptune or hondata if you wanna do it best
 
Back
Top