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I kept saying the tabs will bolt the vband part of the CHRA into the housing! lol

tisk tisk tisk why didnt you at least try man lol... still in the plastic and just trying to eye how it fits. you disappoint me good sir.

the vband ring in the packet is for the dump :) maybe thats why your confused lol

yeah with the 06ll2-20g on the rb25 the egt is getting too hot on 98 as the rear is really too small to for rb25 even with the 10cm. The e85 cheats and allows you to stretch it legs abit.

is that due to the fact the 20g pumps hotter air than the 25g? coz simon and others seem to fair perfectly fine with the T67 25g...... despite having the same turbine wheel

I don't get this "pumps hotter air" that I am reading in threads lately. Where is it coming from?

You spin the same turbo harder for more boost and you will often get higher inlet temps courtesy of compressing the air. The intercooler's job is to remove that heat, which whilst isnt 100% efficient ...will remove the bulk of the higher temps if sized correctly. By the time you add fuel, compress and ignite it I cant see the inlet temps having a dramatic impact on the exhaust temps...it will affect the hp but surely it is negligible with regards to EGT

Then you have the hot side and EGT. They can be higher due to the A/F you are running, the cam and ignition timing etc. Oor higher due to exhaust back pressure in the turbine housing or exhaust system as a whole.

So unless you all go and plumb EGT sensors into your dump pipe with a pressure sensor in the scroll of the turbo then I dont think anyone can comment on whether somehting is fine or not as we dont know the numbers. I know on my old 20G setup with a 10cm housing that the pressure readings I was getting suggested that the housing was too big. My 8cm housing doesnt have a tapping for a pressure gauge so have never measured it...though my TD05-18G 8cm housing does so will be measuring it when I am playing with that setup

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I don't get this "pumps hotter air" that I am reading in threads lately. Where is it coming from?<br />

<br />

You spin the same turbo harder for more boost and you will often get higher inlet temps courtesy of compressing the air. The intercooler's job is to remove that heat, which whilst isnt 100% efficient ...will remove the bulk of the higher temps if sized correctly. By the time you add fuel, compress and ignite it I cant see the inlet temps having a dramatic impact on the exhaust temps...it will affect the hp but surely it is negligible with regards to EGT<br />

<br />

Then you have the hot side and EGT. They can be higher due to the A/F you are running, the cam and ignition timing etc. Oor higher due to exhaust back pressure in the turbine housing or exhaust system as a whole.<br />

<br />

So unless you all go and plumb EGT sensors into your dump pipe with a pressure sensor in the scroll of the turbo then I dont think anyone can comment on whether somehting is fine or not as we dont know the numbers.  I know on my old 20G setup with a 10cm housing that the pressure readings I was getting suggested that the housing was too big. My 8cm housing doesnt have a tapping for a pressure gauge so have never measured it...though my TD05-18G 8cm housing does so will be measuring it when I am playing with that setup

True i think we all may be talking different things.

The problems i keep reffering too with the L2 and some of the other prototypes we see come through are related to backpressure (exh valve to turbo). If we compare SR20 with l2 to rb25 with l2 and assume the exhaust system without turbo (headers, turbine, downpipe, etc.) is the same between both motors we can assume the "base" backpressure will be roughly the same.

If theroetically the backpressure measures at 48psi between the motor and turbine. The 2500cc motor will run into a bottleneck because there is 48psi in the exhaust and only 10psi in the intake (a 4.8:1 ratio). This high ratio keeps the cylinder from scavenging/filling fully and therefore limits power. The 2000cc motor, on the other hand, has 32psi of boost (only a 1.5:1 ratio) to push against the backpressure. Therefore it is able to be much more efficient under these conditions.

The bottom line is, as your motor size increases, your boost level will go down (in order to achieve the same power level). In such a case you will need to maximize the flow potential of your compressor and minimize the restriction of your header system (including the turbine) in order to reach your power goals.

L2-20g is so restrictive on the 25 its is hard to control the heat due on 98 in part to the high ratio of boost to backpressure, therefore we need to run lower boost levels to keep the ratio in check and keep det at bay (diluted charge). E85 allows a more efficientsetup would allow as the diluted charge is still more potent..

We have tested exhaust pressure on a few turbos lately and the ratio of boost to backpressure is way to high, its mostly on guys trying to chase respone via small hot sides on their turbos...

ive found to make good power, generally turboed engine efficiency depends more on low exhaust backpressure than tricks with the cams etc and going too small on the hot side of a turbo and you won’t be able to effectively control EGT’s no matter what.

If you want to monitor heat trends an accurate ir gun will suffice to see trends in temps but a bung is the way to go for real results.

Its hard to control heat at what point, 18psi-22psi where?

cause I have been thinking for a while now to run e85 and low boost for a healthy 280-300..

Is this going to work or should I cut my losses here and just ditch it for a T67 comp

Its hard to control heat at what point, 18psi-22psi where?

cause I have been thinking for a while now to run e85 and low boost for a healthy 280-300..

Is this going to work or should I cut my losses here and just ditch it for a T67 comp

we can make more power on less boost. E85 will help out.

But when you factor in the power people are making , you are asking the lil 20G wheel to flow around 590cfm or 42lbs ...if you look at the compressor map thats right at the end of its efficiency. Sure the E85 will help it along....but a turbo can only flow so much air. So the whole more power at less boost? If you are already making 280rwkws, by more power do you mean 5-10rwkws at 2 or sp psi less???

Guess it's application dependant really too

Doris running hard on the limiter it might be a struggle with heat..

I drive like a little old lady in comparison so it won't as much an issue and maybe is worth the sacrifice for low down response and possibly/hopefully a punchier midrange :D

But when you factor in the power people are making , you are asking the lil 20G wheel to flow around 590cfm or 42lbs ...if you look at the compressor map thats right at the end of its efficiency. Sure the E85 will help it along....but a turbo can only flow so much air. So the whole more power at less boost? If you are already making 280rwkws, by more power do you mean 5-10rwkws at 2 or sp psi less???

around 300max @ less boost generally.

If theroetically the backpressure measures at 48psi between the motor and turbine. The 2500cc motor will run into a bottleneck because there is 48psi in the exhaust and only 10psi in the intake (a 4.8:1 ratio). This high ratio keeps the cylinder from scavenging/filling fully and therefore limits power. The 2000cc motor, on the other hand, has 32psi of boost (only a 1.5:1 ratio) to push against the backpressure. Therefore it is able to be much more efficient under these conditions.

thanx for the explanation there btw .While i get the basic principle here, any chance you could elaborate on how you get these backpressure figures...or are they just derived from testing..

if you have 48psi and 10psi intake, then double the intake to 20psi is that going to double the backpressure pre turbine as well, and how come the 2L has 32psi of boost?

I have been looking at buying one of these turbos, but it seams they are not water cooled. Is this correct? Any real disadvantage to this?

This is the one I'm looking at http://www.ebay.com.au/itm/Kinugawa-Turbocharger-4-Anti-Surge-T67-25G-T3-10-cm-V-Band-Housing-/290714087600?pt=AU_Car_Parts_Accessories&hash=item43afe8f0b0#ht_2379wt_1396

Target is 450hp with a little room for more when a 3L goes in.

You can get a water cooler variant, it will be badged as a TD06SL2 25G

as long as it has the 4" cover and the T3 10cm V band rear it will be the same item with a different CHRA.

However, the water cooled version has the normal TD06 shaft (thinner) and the oil cooled T67 version uses a TD07 shaft (thicker and stronger)

There doesnt seem to be a disadvantage to the T67 mang, but whats wrong with your HG?

thanx for the explanation there btw .While i get the basic principle here, any chance you could elaborate on how you get these backpressure figures...or are they just derived from testing..

if you have 48psi and 10psi intake, then double the intake to 20psi is that going to double the backpressure pre turbine as well, and how come the 2L has 32psi of boost?

we had a period of time when some of the proto turbos coming through would take 8 -10 degrees less timing so we used the egt port in the housing to measure EGT and Pressure (thie pic attached is not mine) to determine exactly what was going on in there pressure wise.

1-8NPTfittingsinturbo.jpg

thanx for the explanation there btw .While i get the basic principle here, any chance you could elaborate on how you get these backpressure figures...or are they just derived from testing.. if you have 48psi and 10psi intake, then double the intake to 20psi is that going to double the backpressure pre turbine as well, and how come the 2L has 32psi of boost?

Ratio works as follows as we work back from the large engine will small turbo scenario.

48psi in exh manifold and only 10psi in inlet manifold works out to a ratio of 4.8:1 in theory if we were to try and get the same 48psi of back pressure in the exhaust manifold on the 2l we would need to have 32psi on the intake based on the 1.5:1 ratio (derived from testing).

You can get a water cooler variant, it will be badged as a TD06SL2 25G

as long as it has the 4" cover and the T3 10cm V band rear it will be the same item with a different CHRA.

However, the water cooled version has the normal TD06 shaft (thinner) and the oil cooled T67 version uses a TD07 shaft (thicker and stronger)

There doesnt seem to be a disadvantage to the T67 mang, but whats wrong with your HG?

Noting is wrong with the hypergear turbo it still works perfectly. I have upgraded to a top mount manifold and Tial WG so the whole setup has changed. I need a new rear housing for the ExGate.

I can sell the turbo to a friend(Including dump oil lines intake pipes 3 actuators) buy a new one and have some cash left over to go towards making a new dump

I was looking at getting Hypergears gt35r equivilent but have not seen any proven results.

Really just weighing up the options i have

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