Suitability of this turbo?

[mark2]

Would appreciate some comments on the suitability of this turbo:
Kinugawa Universal TD04HL 15T OIL Cooled External Wastegate T25 Flange 6cm 280HP | eBay (http://www.ebay.com.au/itm/Kinugawa-Universal-TD04HL-15T-Oil-Cooled-External-Wastegate-T25-Flange-6cm-280HP-/281370043471?pt=AU_Car_Parts_Accessories&hash=item4182f6244f)


I know the TD04HL-19T is well regarded by the experts here, but this one caught my eye, being significantly cheaper and a bit simpler.


Is a wastegate necessary? I ask because many people seem to wire them shut anyway....Seems to be a saving of around $300 for not having the wastegate.

What are the implications of the smaller compressor wheel on the 15T?

I would be happy with usable boost from about 1000 rpm to 2500 rpm, similar to my understanding of how a GT25 a/r 0.49 would perform.

[Blknight.aus]

Depends on how Mich boost you want to run, without getting too far into it I'd say it'll run out of puff at arouse nd 15 psi at around 3000rpm on the Suzie.

No missing the waste gate won't hurt you on that engine with that turbo.sizing you'll need to adjust the pump to suit tho.

[mark2]

Depends on how Mich boost you want to run, without getting too far into it I'd say it'll run out of puff at arouse nd 15 psi at around 3000rpm on the Suzie.

No missing the waste gate won't hurt you on that engine with that turbo.sizing you'll need to adjust the pump to suit tho.

By 'adjust the pump to suit', do you mean wind out the fuel screw?

15 psi at 3000 rpm would do me - no plans to intercool. I'm trying to keep things simple and the lack of wastegate appeals on these lines. Dump pipe would be an easy job to match up to the triangular flange also.

Seems to have the same turbine a/r (0.49) as the 19T but a smaller compressor and possibly one less blade on the compresser also, if that makes a diference. So without doing the calculations (because I cant), would I be right in guessing it would spool up a bit earlier than the 19T, but make less overall boost, becoming restrictive over around 3000 rpm?

Is it going to be better than one of the factory turbos, as the consensus seems to be that they're not that great?

The price on these is roughly comparable to a second hand T25 + a DIY rebuild kit - so looks like good value.

[Dougal]

You want a wastegate. Without it'll turn into an exhaust brake by supplying too much boost.

[mark2]

You want a wastegate. Without it'll turn into an exhaust brake by supplying too much boost.

So help me understand this. How is wiring a wastegate shut different from not having a wastegate?

[Dougal]

So help me understand this. How is wiring a wastegate shut different from not having a wastegate?

It's not. Both are silly.

Without a functioning wastegate you need a much bigger exhaust housing and performance starts to bring the suck.

[mark2]

It's not. Both are silly.

Without a functioning wastegate you need a much bigger exhaust housing and performance starts to bring the suck.

I still dont get it. I thought there were quite a few on here who had wired their wastegates shut, to allow the turbo to develop the boost it is capable of. If this turbo for example can only make say 15 psi with a n/a pump, why is a wastegate necessary? Does a wastegate do more than just keep boost pressure within safe limits?

I know I'm probably overlooking some obvious fundamental of turbo theory.....

[Dougal]

the wastegate allows more exhaust flow and lower exhaust pressure once enough boost has been developed. Letting the engine rev more readily and produce more power.

With a shut wastegate unless you have the fuel to match the boost keeps climbing, the exhaust pressure keeps climbing and power is lost to pumping loss.

With no intercooler my egt is the same at 20 and 24psi boost. But with the wastegate shut for 24psi the engine hits a power wall around 2500rpm.

[Blknight.aus]

run with whats dougals saying for the application your looking at setting up, it will be better than a NA 4bd1 at the bottom half but will hit a wall Im gussing around 3K RPM@~15psi.

having had a slightly better look at the numbers (and it wasnt that good) I dont think that exhaust back pressure is whats going to kill you in your intended application I suspect it will be compressor slip first and then you'll choke up on the the turbine..

very very vaguely

if you're going to run without a wastegate you want to run some higher pressure and flow rates on the compressor side (really really simply you want a bigger/better compressor wheel than the turbine) you also want a very fast free flowing exhaust with a larger apature on the turbine housing exhaust.

A wastegateless system should never be permitted to hit compressor slip as once that occurs the turbo can "run-away" as theres less load on the compressor wheel once it starts to slip. what follows after that is s quick death of the bearings/shaft and in extreme repeated cases shearing off of either the wheel as a whole or blades

[isuzurover]

I still dont get it. I thought there were quite a few on here who had wired their wastegates shut, to allow the turbo to develop the boost it is capable of. If this turbo for example can only make say 15 psi with a n/a pump, why is a wastegate necessary? Does a wastegate do more than just keep boost pressure within safe limits?

I know I'm probably overlooking some obvious fundamental of turbo theory.....

Some of us have a relatively large turbo that works very well on the highway, but which came from the factory with a wastegate set to 9 psi. In this case wiring it shut is ok, as the turbo only ever manages to reach max desired boost anyway.

[rar110]

the wastegate allows more exhaust flow and lower exhaust pressure once enough boost has been developed. Letting the engine rev more readily and produce more power.

With a shut wastegate unless you have the fuel to match the boost keeps climbing, the exhaust pressure keeps climbing and power is lost to pumping loss.

With no intercooler my egt is the same at 20 and 24psi boost. But with the wastegate shut for 24psi the engine hits a power wall around 2500rpm.

For years Ive had a valve setup to vent pressure before the wastegate actuator (activates about 9 or 10psi) which deactivated the actuator keeping the wastegate shut. This improved the 4BD1 performance IMO and resulted in lowered EGTs. My theory was not enough air was being pushed into the motor because the turbo wasn't working to full capacity due to too much exhaust bypassing.

Tonight I acted on Dougal's post and adjusted the valve so it vents less and theoretically let some pressure to the actuator, causing the waste gate to open to some extent. This improved the performance again IMO and again lowered EGTs in the higher rev range. The engine seemed to rev easier and run a little quieter.

My Auberins boost gauge is not set properly so I don't know for sure what boost I'm running. It reads 5 or 6 psi at idle which isn't right and reaches about 26psi. Maybe its boosting to 20psi.

Maybe Im imagining the whole thing. At least the lower EGTs are a measurable improvement. Is there a wastegate actuator that's set to 20psi.

[Dougal]

For years Ive had a valve setup to vent pressure before the wastegate actuator (activates about 9 or 10psi) which deactivated the actuator keeping the wastegate shut. This improved the 4BD1 performance IMO and resulted in lowered EGTs. My theory was not enough air was being pushed into the motor because the turbo wasn't working to full capacity due to too much exhaust bypassing.

Tonight I acted on Dougal's post and adjusted the valve so it vents less and theoretically let some pressure to the actuator, causing the waste gate to open to some extent. This improved the performance again IMO and again lowered EGTs in the higher rev range. The engine seemed to rev easier and run a little quieter.

My Auberins boost gauge is not set properly so I don't know for sure what boost I'm running. It reads 5 or 6 psi at idle which isn't right and reaches about 26psi. Maybe its boosting to 20psi.

Maybe Im imagining the whole thing. At least the lower EGTs are a measurable improvement. Is there a wastegate actuator that's set to 20psi.

And your T28 is larger than most of the turbos people are using. So your improvement is smaller than most would get.

I bought a 22psi actuator off Ebay and currently running it. I had to run a lot of preload and it's holding boost at 20psi on my T25.
Without the wastegate I had boost climbing to 24psi but less power (exhaust was being choked and would hit a wall around 2,500rpm) and the same EGT. With the functioning wastegate I can rev out to the governor.