Is it worth it to purchase a 14b turbo and install ki?

[96gstdsm]

Well i have been looking into getting a new turbo. I plan to get the evo3 16g turbo in the future. I don't feel like spending that much money yet, as i don't know if i will have this car for a long time or not. I love the car but the fwd thing is a bit annoying. But anyways, my question here is, is it worth it for performance to buy a used 14b turbo for around $100 and also a 2g install kit. Would i see nice gains over stock t-25 power and stock fuel system? I would plan to run the 14b around 15 or 16 hopefully. I know bench racing is not allowed on here, but i am just curious as to what sort of gains you are able to get with just swapping over to the 14b before i purchase it. Whats the highest psi i could run while still using the stock fuel setup? Would i get much better top end?
Any input i would really appreciate. I figure if there are nice gains it would be a nice temporary swap.
---Ryan.

 

[IslandTSI]

You8 might see a small gain by just bolting it up. Real gains will be seen when you turn the boost up however which requires more fuel/logging etc.

The 14b is a very capable turbo. I am planning on getting one and using it as I add more fuel untill I feel I can use a 16g to it's potential. You can get a 14b for ~$100 and if it breaks its not expensive to replace

 

[96gstdsm]

You8 might see a small gain by just bolting it up. Real gains will be seen when you turn the boost up however which requires more fuel/logging etc.

The 14b is a very capable turbo. I am planning on getting one and using it as I add more fuel untill I feel I can use a 16g to it's potential. You can get a 14b for ~$100 and if it breaks its not expensive to replace

What psi could i run it with stock fuel setup? Could i run it up to like 17 or 16 psi? If so would that be a pretty noticeable gain? Just trying to see if it is worth it to upgrade for cheap and get enough power to make it worth while.

 

[pooker]

Using the 1g bov you could run that, I think its worth it compare your options. A reputable 16g from a vendor is in the 500 dollar range compared to getting a 14b for 100 bucks. People underestimate them.

 

[Splitpi]

Run 14 psi. You need to get a means to control fuel such as AFC or DSMLink inorder to get a real advantage past that magic 14 psi number (really nothing magical, just a safe and prudent value). Also if you rewire your stock fuel pump you will be set for 550 cc and BARELY 650 cc (at 80% duty cycle) injectors.

If you do decide to turn it up to 17 psi get a logger and make sure nothing bad happens.

Edit:
If you purchase a used 14b thouroughly inspect it to make sure no fins are bent, shafts aren't bent and that their is no in-out, up-down shaft play. Also you can get lucky like I did and purchase a 14b and actually get a big 16G because the seller didn't realize what he had. Course I did have to have mine rebuilt... but it was still cheaper (with getting it professionally ported and polished) than purchasing a new one that was not ported and polished.

 

[gsxeclipse97]

just bolting the turbo up you will gain quite a bit of power. I wouldn't run more than 15psi on a stock system. There was a huge difference in power as far as i could tell. Buy the install kit it will make you life very easy. I didn't and i wish i would have now. So get the kit and when you get your 16g it will be easy just to bolt that turbo in.

 

[96gstdsm]

just bolting the turbo up you will gain quite a bit of power. I wouldn't run more than 15psi on a stock system. There was a huge difference in power as far as i could tell. Buy the install kit it will make you life very easy. I didn't and i wish i would have now. So get the kit and when you get your 16g it will be easy just to bolt that turbo in.

Awesome that sounds good. This is from your personal experience? Does anyone have dyno numbers to show what the different turbo's would do with a stock fuel setup? Or a ballpark figure? Once again i understand the whole no bench racing thing, but when trying to figure out if it is worth it, numbers do matter sometimes. At 15 psi with the 14b or 15 psi with the t-25 would the performance be noticeably faster?

 

[Splitpi]

At 15 psi with the 14b or 15 psi with the t-25 would the performance be noticeably faster?

No, I don't believe there will be any significant difference @ 14 psi. I will look at a the flow chart to verify how much extra CFM @ 14 psi the 14b is pushing versus the t25 @ 14 psi. But I believe it to be little differance if any.

http://not2fast.wryday.com/turbo/maps/

 

[Merkles]

The 14b is a very nice turbo to use until you get all of your supporting mods. Thats what I am doing. It is definatly better then the t-2small because it will not drop off as easy in the higher RPM range.

 

[kevingst]

I used the 14b for awhile and loved it leaps and bounds over the T25. With no means to tune I ran it at 16psi on the stock system. Did the fuel pump rewire and threw on a 190lph walbro and boosted up to 18 with no problems running anywhere from 11.5:1 to 12:1 afr's. Threw on an afc and was boosting 20psi. Ran like a raped ape but would get insane fuel cut on anything less than 93oct, even cut on that on cold days. But at 20psi it was pretty useless above 5-5.5k rpms.

 

[Splitpi]

Assumptions:
Atmosphere pressure = 14.7 psi (sea level)
Gauge Reading = 14 psi (desired pressure at manifold)
Inlet Depression pressure = 1 psi (pressure loss at the turbo inlet due to piping, filter, etc)
Brake Specific Fuel Consumption (BSFC) = .55
A/F ratio = 11:1 (ideal boost fuel ratio when hitting the gauge reading above)

Pressure Ratio = (Gauge Reading + Atmosphere Pressure)/(Atmosphere Pressure - Inlet Depression Pressure) = (14+14.7)/(14.7-1) = 28.7/13.7 = 2.1

From the pressure ratio of 2.1 we can look at the Compressor maps for both the TD05-14b and T25 (I am using the 60 TRIM 0.48 A/R map) and correlate the range of possible airflows at 2.1 pressure ratio. I will call the value "Wa" for the hp equation later.

http://not2fast.wryday.com/turbo/maps/

T25 Max = ~24 lb/min
T25 Min = ~7 lb/min
14b Max = ~32.4 lb/min (lb/min = 162.04*m^3/s)
14b Min = ~9.8 lb/min (lb/min = 162.04*m^3/s)

Then using a guestimate for potential HP based upon ideal conditions and the assumptions above, we use this equation:

HP = Wa/(A/F * BSFC/60) = Wa/(11*0.55/60) = Wa/0.1008

So:

HP (T25 Max @ 2.1) = 24/0.1008 = 238 hp
HP (T25 Min @ 2.1) = 7/0.1008 = 69 hp
HP (14b Max @ 2.1) = 32.4/0.1008 = 321 hp
HP (14b Min @ 2.1) = 9.8/0.1008 = 97 hp

I should note that I am not narrowing the scope of the map to be in a specific VE or Volumetric Efficiancy of the turbo nor at a specific operational speed of the turbo. I.e. going from border line choke to blowing hot air. But say for instance you wanted the turbo to remain in 72% efficiency or better for the assumptions above. Thus going back to the map and looking at the greatest flow rate @ 72% efficiancy and 2.1 ratio we get:

T25 = 20.1 lb/min
14b = 25.9 lb/min

HP (T25 @72%) = 20.1/0.1008 = 199 hp
HP (14b @72%) = 25.9/0.1008 = 257 hp

So I guess I was wrong about it being insignifficant as 50hp at the crank is pretty significant and is a 23% increase in power (with a few cavaet discussed at the end, i.e. if RPMs was not an issue and you could rev to 9k). As a note, assuming 80% duty cycle on the injectors and a BSFC = 0.55, 257 hp at the crank would require 400 cc injectors or well within stock fuel injectors.

Edit:
One final note, for those of you with a big 16G and the above assumptions of peak 71-72% VE:
B16G Max (at 2.1 Pressure Ratio) = 40 lb/min = 402 hp
B16G Min (at 2.1 Pressure Ratio) = 13 lb/min = 129 hp
B16G (at peak 71% VE and 2.1 Pressure Ratio) = ~31 lb/min = 307 hp

However, the true value lays int that the ~71-72% VE streches to about 2.45 ratio @ 34 lb/min or 337 hp or 511 cc injectors. Meaning at 18.9 psi you still have plenty of potential in the turbo.

RPMs:
You can also calculate the RPMs of the engine necessary at a specific VE, psi and air flow using this formula:

RPM = (2*Wa*639.6*(460+Manifold Temperature))/((Gauge Reading+Atmosphere Pressure)*VE*Engine Displacement (in cci))
or using T25 @ 14 psi @ 72%VE and 90 degrees F Manifold
T25 RPM = (2*20.1*639.6*(460+90))/((14+14.7)*0.72*122.04) = 5608 RPMs
14b RPM = (2*25.9*639.6*(460+90))/((14+14.7)*0.72*122.04) = 7226 RPMs
B16G RPM = (2*31*639.6*(460+90))/((14+14.7)*0.71*122.04) = 8770 RPMs

What this means is a 14b at 14 psi will hold boost all the way to red line versus the T25 which putters out at 5608 RPM. Also I should point out that whether B16G, T25 or 14b @ 5608 RPMs @ 14 psi @72% VE and with 90 degrees at manifold (i.e. all variables the same and solve for Wa) you will discover that ALL turbos have a potential for 199 hp at the crank irregardless of model. That is the maximum potential the engine can produce given its 2 liter size. However, as you rev past the RPMs the 14b and 16G continue to make more power as they are still in the VE band. And if you increase manifold pressure you decrease the RPMs when a given flow will occur (assuming same RPMs, VE and temp). The problem with the T25 is anything much past 17 psi is really just hot air and very low VE versus the other turbos. With the above said, the real world VE for 14b is 70% @ 14psi @ 20.1 lb/min and b16G is 65% @ 14 psi @ 20.1 lb/min, meaning your operating the 14b and 16G closer to the surge line (left hand boundry, meaning the turbos are close to being too large for that pressure that you want to have the specific air flow) versus the T25 who is operating closer to the choke line (right hand boundry, meaning the turbo is close no longer efficient < 58% and iternal RPMs of the turbo is nearing safety margins). So with the 16G and 14b you would assume a higher flow rate to compensate and move to a move central position on the map... and adjust fuel accordingly.

One Final Note:
Assuming we could adjust boost and VE remained at .72%, temp = 90 and 5608 RPMs for all turbos, we would find that:

T25 makes 238 hp at 19.6 psi as Measured
14b makes 321 hp at 31 psi as Measured
B16G makes 402 hp at 43 psi as Measured

This is do to the fact that the RPMs were locked at 5608 and I took the max potential for each turbo (though inactuality any turbo that can be at 72% efficiancy across the pressure ratio and flow will make those numbers at that psi). Reality is however that effiency drops considerably so these values will not be realized and not attainable in real life. However, I think I dramatized my point enough at the same RPM and psi of boost and assuming two turbos are operating in the same effiency (VE) and intake temp they will yeild identical power outputs. However if RPM and VE is not specified and only boost is capped, the values can very greatly. Hence when speaking about turbos you must mention the boost you want, what VE and at what RPMs. Then it can be calculated if the turbo is even able to do that or find the correct VE and RPMs. There are so many variables to fully answer such a basic question as I have demonstrated on how to make more or less power based upon RPMs, VE and boost ... but the simplest answer is that they are identical out same boost...

 

[96gstdsm]

Very interesting splitpi. Thanks a lot for that in depth chart!! Well it looks to me like it is definately worth it to get a 14b for the mean time! I am not so great at reading those charts so i have a couple questions concerning it. The 257 hp at the crank is based on stock 450cc injectors and at 14 psi correct? From that info is there something showing the difference in hp between the t-25 and 14b at 14 psi? Sorry for the not quite understanding everything on that chart, I'm new to all the terms. It looks like you are saying the 14b at 14 psi would equate under those circumstances to 257 at the crank. What would the t-25 be at under the same boost level and all?
Thanks again for the assistance!

 

[Splitpi]

What RPM and VE do you want to make 14 psi at? From my chart above the breakdown of the chart (or attempt there of), 257 hp at the crank can be acheived by a 14b @ 14 psi and a VE of 72% by 7226 RPM's.

A T25 won't have a VE of 72% across its chart for 14 PSI. Instead we work the equation backwards and say what will it produce at 7226 RPMs and 14 psi. However this leaves us with two unkowns, Wa (which we need to calculate HP) and VE. Reducing the math, we get:

35.96VE = Wa

But, we know A/F and BSFC and HP, so we can calculate Wa from the HP equation:

257 = Wa / (11 * .55/60) and solving for Wa

Wa = 25.9 lb/min

So VE = 25.9/35.96 = 72% efficiency

Here is the problem however if I look on the chart, a T25 won't correspond to that, meaning that is impossible with the turbo. But I can cross reference 25.9 lb/min flow and 2.1 ratio, I will see that it is past the choke line of the turbo by ~1.2 lb/min. So adjusting backwards the flow to 24.7 lb/min @ 2.1 ratio yeilds 65% VE.

So now we recalculate:
HP = 24.7/(11*.55/60) = 245 hp
RPM = (2*24.7*639.6*550)/(28.7*.60*122) = 8272 RPMs

So a T25 max out at 8272RPMs @ 60% VE @ 14 psi yeilding 245 hp.

Edit:

I should point out that temperature is assumed constant across all VE and turbos... IE w have a very large and efficient IC at work to maintain a 90 degree intake manifold temperature irregardless of how hard or little the turbo is working. So this still isn't a real world scenario... but it is close.

 

[calreef18]

It is worth it to get the 14b, that's what I upgraded to and am still on stock injectors with a rewired pump and I was able to tune to 16psi, but I do have a logger. The pull is definitely nice, even with the slightly boost leak I haven't been able to fix recently. If you are a little low on funds you don't need to buy the whole kit, but it is nice to have. I did mine by reusing the 1g oil return, bought a new feed line and some gaskets, and reused the t25 water lines, just had to bend them,

 

[Merkles]

I did mine by reusing the 1g oil return, bought a new feed line and some gaskets, and reused the t25 water lines, just had to bend them,

You can even re-use the 2G oil return line, it just involves alittle bit of filing down. Thats what i did and havnt had any issues with leaking or anything.

 

[gsxeclipse97]

Awesome that sounds good. This is from your personal experience? Does anyone have dyno numbers to show what the different turbo's would do with a stock fuel setup? Or a ballpark figure? Once again i understand the whole no bench racing thing, but when trying to figure out if it is worth it, numbers do matter sometimes. At 15 psi with the 14b or 15 psi with the t-25 would the performance be noticeably faster?

I don't have power numbers but as far as driving experince there is a large difference in power. But i also at the time had the 7-bolt motor and head apex n1 cat back mbc set at 15psi greddy bov with stock ic piping and intercooler.. there was other stuff on the car but this is the performace stuff that you would want to know for how you car will react

 

[gsxeclipse97]

You can even re-use the 2G oil return line, it just involves alittle bit of filing down. Thats what i did and havnt had any issues with leaking or anything.

I would just buy the kit i tried to use the 2g oil line and that in it self was a pain in the rear to even get off the car. but it is a good turbo.

 

[DSMunknown]

Personally, I despise the J-pipe.

 

[PieEyedPiper]

Great info guys, that write up is awesome.
I'm now seriously considering getting the 14b for my car, rather than port my T-25.

 

[calreef18]

Great info guys, that write up is awesome.
I'm now seriously considering getting the 14b for my car, rather than port my T-25.

Go for it man . The logger function I have probably isn't too accurate, but fwiw on my auto gst spyder I went from 0-60 7.4s to 6.4s after the 14b install.

 

[96gstdsm]

Go for it man . The logger function I have probably isn't too accurate, but fwiw on my auto gst spyder I went from 0-60 7.4s to 6.4s after the 14b install.

What psi was the t-25 at and what psi was the 14b at?

 

[Blackmitzu]

A really good starting setup is a 14b, walbro 255 with 550s and 2gmaf. If you have 550s and a 2gmaf combo you really dont need an safc. This was my first setup on my first dsm and i ran a 12.87 at 20psi. O and you will also need a metal head gasket and arp headstuds to handle the high boost.

 

[RedTurboEclipse]

A really good starting setup is a 14b, walbro 255 with 550s and 2gmaf. If you have 550s and a 2gmaf combo you really dont need an safc. This was my first setup on my first dsm and i ran a 12.87 at 20psi. O and you will also need a metal head gasket and arp headstuds to handle the high boost.

High boost as in 25+ PSI? As there are several posts and claims/logs from owners who have ran 24 just fine, myself included. Or did you mean to say high boost safely without worrying.

 

[Splitpi]

A really good starting setup is a 14b, walbro 255 with 550s and 2gmaf. If you have 550s and a 2gmaf combo you really dont need an safc. This was my first setup on my first dsm and i ran a 12.87 at 20psi. O and you will also need a metal head gasket and arp headstuds to handle the high boost.

Guessing 3200 lbs for you and your car @ 12.8s quarter mile = 356 hp at the crank. Assuming 11 AFR and BFSC of 0.55:

Wa = 35.9 lb/min = 0.214 m^3/s
Boost = 20 psi ~=34.7 psi absolute
Pressure ratio = 34.7/13.7 = 2.5

Looking at the chart, you were at ~65% VE border for the 14b and nearing the choke line but not past it. You could have taken it a little further still, but only seen marginal gains if any due to droping into the 60% VE

 

[96gstdsm]

A really good starting setup is a 14b, walbro 255 with 550s and 2gmaf. If you have 550s and a 2gmaf combo you really dont need an safc. This was my first setup on my first dsm and i ran a 12.87 at 20psi. O and you will also need a metal head gasket and arp headstuds to handle the high boost.

At what psi would I need to replace the headgasket considering it is in good shape now? And arp headstuds I was told I would not need untill I had like over 400hp! Is that not true? If i'm running 15 psi or even like 18 i wouldn't need head gasket would I? Or head studs? Over 15 psi i would need to upgrade my fuel and all though correct?