Spool time t25 vs 14b

[97egl]

Is there any noticeable difference in spool times between the 14b and T25. Looked in some old forums and all I found was people saying the t25 sucks compared to the 14b and runs out of steam around 6000 rpm but couldn't find any real info on difference in spool times. Also if you know of anything that can be done but look factory to decrease spool times that would be helpful.

If you want the full story of why I need to know this keep reading.

Going to be taking one of my cars to a very small 1/5 mile speedway for a 30 minute enduro race. The track is small and slow, running in 2nd gear I am only going to be doing about 3000 rpm coming out of the corners and maybe 5500 at the most going into them. I know the 14b already spools quite quickly compared to larger turbos but on a 1/5 mile track there is only a couple seconds of being in the gas before letting off for the next corner so I want to build boost as quickly as possible. Usually on larger tracks I am exiting corners at 4000-4500 rpm and it still takes a second for the boost to build so with lower rpms I am thinking its going to take the whole straight away to build full boost.

I am aware that I can get in the gas while still in the brakes on corner exit to spool the turbo a little but in the past when I have done this on larger tracks the brakes get so hot the fluid starts boiling and they fade out. I am running DOT 5.1 to try and combat that but all that does is make them go for longer before fading but they still fade out, so I only use that technique when I am trying to get around a difficult competitor.

Thanks guys

 

[chrysler kid]

Most of my spool lag in my 14b is from the front mount intercooler, and not from the turbo itself. To clarify, the turbo will build 5 psi pretty quickly but the push to 15psi takes another second

In terms of competitive nature, I would be more concerned about the health of the turbo.

The t25 is the ultimate turbo for a car driven every day, however the difference in a half throttle and full throttle power is zero. The turbo feels like it doesnt have extra power at full throttle.

The 14b should be happier to send power at the mid to upper rpm range, it probably wont feel like extra power, but the engine will receive more air flow in your usable range.

If you are going to add a front mount intercooler i suggest just skipping the 14b all together, and get a 16g that will push through the pressure loss of a large intercooler without the extra second of "lag"

So yes the car will have extra power in the rpm range youre seeking. As far as being faster, im not sure you would notice much of a competitive advantage. Full bolt ons my t25 made 205 whp, most people with a 14b say they make 210-220 whp.

 

[97egl]

Most of my spool lag in my 14b is from the front mount intercooler, and not from the turbo itself. To clarify, the turbo will build 5 psi pretty quickly but the push to 15psi takes another second

In terms of competitive nature, I would be more concerned about the health of the turbo.

The t25 is the ultimate turbo for a car driven every day, however the difference in a half throttle and full throttle power is zero. The turbo feels like it doesnt have extra power at full throttle.

The 14b should be happier to send power at the mid to upper rpm range, it probably wont feel like extra power, but the engine will receive more air flow in your usable range.

If you are going to add a front mount intercooler i suggest just skipping the 14b all together, and get a 16g that will push through the pressure loss of a large intercooler without the extra second of "lag"

So yes the car will have extra power in the rpm range youre seeking. As far as being faster, im not sure you would notice much of a competitive advantage. Full bolt ons my t25 made 205 whp, most people with a 14b say they make 210-220 whp.

So I actually have a 14b and was wondering about "downgrading" to a t25. It's a factory/stock class so I can't run a front mount. Even if I had to sacrifice a few top end horsepower to get higher boost in lower rpm would be a good trade off.

I guess a dyno graph of the 2 side by side would be the best comparison but I seriously doubt anyone has a dyno of a t25 on a manual transmission car. Be surprised if there is even a dyno of a stock 14b out there since there is no reason to get on a dyno without mods

 

[JusMX141]

In second gear exiting a corner under load at 3000 you'll already be in the power range of either turbo...so I'd go for the one which would pull longer, and that's definitely the 14B.

 

[97egl]

In second gear exiting a corner under load at 3000 you'll already be in the power range of either turbo...so I'd go for the one which would pull longer, and that's definitely the 14B.

Well if you'd use the 14B I'll definitely just stick with that. Thanks!

 

[JusMX141]

The Garrett TB2566 (recognized as the T25) was chosen as a way to boost torque and throttle response on 2G cars after complaints that 1G's were rather lethargic. Intake ports got smaller, throttle body got smaller as well, compression was raised, and rods were lightened to reduce reciprocating mass of the rotating assembly in addition to the turbo shrinking from 43mm to 38.5mm. Had Mitsubishi made the changes but kept the 14B turbo in place on 2G manuals, factory power output would've likely been 20-30 horsepower higher than it was with the TB2566.

Still unsure why they chose Garrett as the turbocharger supplier being they have their own turbocharger company, and even auto 1G's came with a 40mm TD04 13G unit which would've been a suitable size.

 

[curt-s]

I think we can chalk the reasoning up to the same thought process which put low Z injectors in the turbo models.

 

[chrysler kid]

So I actually have a 14b and was wondering about "downgrading" to a t25. It's a factory/stock class so I can't run a front mount. Even if I had to sacrifice a few top end horsepower to get higher boost in lower rpm would be a good trade off.

I guess a dyno graph of the 2 side by side would be the best comparison but I seriously doubt anyone has a dyno of a t25 on a manual transmission car. Be surprised if there is even a dyno of a stock 14b out there since there is no reason to get on a dyno without mods

If youre wondering, the t25 is by far the more responsive turbo. If you said this is in a parking lot autocross event that takes place in second gear at 30mph to 50 mph, this t25 is for you

If its a classification issue, you may be able to bend the rules by stating it is the factory turbo for the 94 mitsubishi eclipse, as the original turbo failed. Thus you should be able to run in the same class as the 1994 eclipse since its the same turbo.

I highly doubt anyone has bothered to port the exhaust housing of a t25, it may offer marginal output gains. But again best case scenario running 18psi with no cat and full turbo back exhaust my 2g made 205whp with an extremely peaked power curve above 5500