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lahondal

Which turbo for Turbo8v

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lahondal

Hi all. 

 

We have finished a turbo 8v hillclimb 205, and for this season we have to rebuild the turbo as its smoking badly (and its the second time so we are thinking it dont cope the effort of racing purposes). 

 

So we are about to choosing a new turbo, and we have thought to buy a new GT25R, like this:

 

https://www.dp-engineering.nl/garrett-gt25r-gt2554r.html

 

The engine is a full rebuilded xu10 8v with:

-Dkz cam

-Custom turbo tubular manifold with 34mm ID primaries. 

-Nissan 200sx turbo, a T28. 

-Straight 57mm ID exhaust without any silencer. 

-Front IC. 

 

It delivers 205hp and 310nm at 1bar, with a very flat torque curve. I have attached the dyno plot. The mapper said that more boost was not raising the power, so we think we have a bottleneck somewhere. 

 

We had some disappointment because the power figure as we were hoping for more power, and dont know if a bigger/better turbo will shift the power upper in the rev range and therefore bettee power. 

 

At the moment there is very little turbo lag, which is very useful for racing. 

 

Open to advices about which turbo buy.... 

 

Thanks in advance. 

IMG-20191109-WA0035.jpg

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welshpug

depends very much on space available, the flange you have used and whether you can weld or know a welder that can weld on a different flange if required, we well as the likely downpipe mods required.

 

how much power do you want?

 

probably worthwhile getting a proper turbo camshaft upgrade, 8v cams aren't expensive.

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Tom Fenton

The cam is crap, out something in that lets it breathe.

I finished off a xu9 turbo for Paul Higgs a few years ago, flowed head and a fast road NA cam, it made 250bhp with a roller bearing GT2560 and was fabulous to drive, on boost from 2500rpm and then it would rev to 7000rpm not tailing off.

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petert

You could do like my 16V, with a TD05H twin scroll, internally gated. It makes construction easy and it will have great throttle response. Hard to beat the value at approx. AUS$1800 for a quality custom turbo. As you're making a new manifold, plan it correctly and have 1-4 and 2-3 collectors, mild steel, coated inside and out.

Resized_20200227_173854.jpeg

Resized_20200227_173906.jpeg

Resized_20200227_173919.jpeg

Edited by petert

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wicked
10 hours ago, Tom Fenton said:

The cam is crap, out something in that lets it breathe.

I finished off a xu9 turbo for Paul Higgs a few years ago, flowed head and a fast road NA cam, it made 250bhp with a roller bearing GT2560 and was fabulous to drive, on boost from 2500rpm and then it would rev to 7000rpm not tailing off.

He already has an NA cam, but if budget allows, I would get the catcams turbo cam + remap.

Secondly a better turbo. The T28 seems to let go from 4000rpm onwards. On my previous engine (Tct) I had a dkz cam and TD04HL-15T turbo; it kept up a bit longer,  resulting in similar torque, but more power at slightly less boost. 

My pick would be the GT2560 as well, since you already have the manifold and it probably it is an easy substitute for the T28. 

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camgti
On 4/3/2020 at 9:22 AM, petert said:

You could do like my 16V, with a TD05H twin scroll, internally gated. It makes construction easy and it will have great throttle response. Hard to beat the value at approx. AUS$1800 for a quality custom turbo. As you're making a new manifold, plan it correctly and have 1-4 and 2-3 collectors, mild steel, coated inside and out.

Resized_20200227_173854.jpeg

Resized_20200227_173906.jpeg

Resized_20200227_173919.jpeg

Keep it in ur pants there Pete! 
 

You need more flow from the turbo and cam. A Gt2868 will probably be more of what your after. Shifting the power up that curve a bit. 

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petert

I thought a TD05 was equivalent to a GT28? Sure, you could probably get a 2.5" inlet, but mine is otherwise spec'd for 2L.

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wicked

Without the trim, TD05 doesn't say that much; other that it's a medium sized one.

GT2560 + catcams turbo cam + some other mods have been proven to hit the 300bhp mark, and kicks in hard. Don't think you need a bigger one on a hill climB car.... 

Edited by wicked
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lahondal

Well, we are not searching for a high power target, the car pulls enough as it is, but the turbo needs to be changed (smokes badly at idle, not on boost) and we want to buy it once.

 

We search for a easy replacement turbo maybe thinking on a future engine upgrade like cam for example. Not so ambicious to 300hp, maybe 230ish mark is really fine for us. 

 

We will need to upgrade some parts too when doing that power rise try, like inlet piping (2" at the moment) or exhaust. 

 

Forgot to say the car haves an ecumaster black ecu, so remapping is easy (a 3hour trip to mapper only). 

 

Room is not a problem as i have done the manifold myself thinking in a turbo upgrade, so i have done it as a top mount turbo, i have attached a pic. 

 

Flange is t25/t28 pattern. 

 

Thanks for all the replies, im happy for that. 

3456998343477469861.JPG

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opticaltrigger
On 4/2/2020 at 9:12 PM, lahondal said:
On 4/2/2020 at 9:12 PM, lahondal said:

It delivers 205hp and 310nm at 1bar, with a very flat torque curve. I have attached the dyno plot. The mapper said that more boost was not raising the power, so we think we have a bottleneck somewhere.

 

Hi Iahondal, great to see your car back again, and looking good.

If you have a data log from that dyno pull above, it would be great to see it, things like the IAT's, ignition advance, duty cycles, etc.

 

I agree with Wicked on the cam and definitely on the GT2560 . Perhaps it's that which bottlenecks things for you a bit.

If you did go for the combination of the Catcam and the GT2560 you could dial in the power that you want with that, and it would be a really, really tasty motor. Especially with that ECU Master you've got it running through... ( Nice one.... ).

 

Great project Iahondal,

All the best,

O.T.

Edited by opticaltrigger

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wicked
On 4/4/2020 at 10:22 PM, lahondal said:

Well, we are not searching for a high power target, the car pulls enough as it is, but the turbo needs to be changed (smokes badly at idle, not on boost) and we want to buy it once.

 

We search for a easy replacement turbo maybe thinking on a future engine upgrade like cam for example. Not so ambicious to 300hp, maybe 230ish mark is really fine for us. 

 

If you really don't want more power in future, the GT2554R is also a valid choice; bit quicker spool and probably plug and play on your current setup/manifold.  But if you ever want to go for higher power, you need to buy twice. 

The GT2560 can midrange rpm easily pump 1.4bar cold air even with turbo cam and bang 400+Nm on tct engine, so your clutch needs be capable of that and decent boost control as well...  So best choice well be dependent on your (future) budget. 

Edited by wicked

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lahondal

Some time passed from this post. 

 

This week should arrive the catcams turbo cam, the gt2560r turbo and MLS headgasket for reliability reason as we have at the moment the stock turbo HG. 

 

Hope for bump up the power at least 25-30hp and we will be superhappy with that. 

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Daniel306

Iv got a GT2871r. it will make 14psi by 3000 rpm in Close loop boost and still on the standard cam

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lahondal

Hi. 

 

Some time passed and finally i have followed the advises and managed to start the car again. 

 

Final modifications were:

 

GT2560RS

Catcams turbo cam + pulley

Mls headgasket

New 3" downpipe and exhaust with side exit. 

Revised turbo air inlet (3" and cold air from bonnet scoop). 

Revised (44 to 48mm and minimum bends) turbo to ic pipe. 

Revised turbo oil outlet. 

Fitted turbo water cooling. 

 

The turbo makes a "coasting down bearing noise" right after shutdown engine, i think can this be normal on BB turbos??? 

 

hdr.jpg

 

Hope to hit the 230mark.

 

Will post results when covid allow us to take the car to mapping. 

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petert

That looks great. Looking forward to seeing the results.

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wicked

I think it should easily make the 230mark. 

 

I had 225bhp with TT manifold, TD04HL and DKZ cam @0.9bar and a friend make 240-ish with TT manifold, GT2554 and catcams. 

The TT manifold doesn't work very well with high flow and gives reversion -> knock.
Given that you have a tubular manifold, you will have less issues with knock, but we aware that the catcams has significant overlap and make it sensitive to knock if the exhaust manifold is restrictive.

From my experience, single elektrode (NGK BPR*ES) spark plugs work best to avoid knock. 

With the catcams, your powerband will move up in rpm and that likely will make you hit the 230mark already with similar torque/boost you have now.

 

Keep us posted...

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lahondal

Well, in reality its not a "pure" tubular manifold, it still have not equal lenght runners, 38mm ID pipes IIRC. Cilinders 1 and 4 have a 2.5x aprox more travel than 2 and 3, and then discharge in a common little chamber. 

 

I dont know its performance as i have built it myself only hoping that would be better than the crap original manifold. 

IMG_20200924_201246.jpg

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wicked

Time will tell.... 

 

Still it looks better in terms of backpressure compared to OEM or TT manifold. 

The TT manifold is great wrt form factor and spool, but not for high end. Just not meant for big HP numbers.

dp-engineering-turbo-tu-8-valve-manifold

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lahondal

Hi all again. 

 

Yesterday we took the car to the rolling road. Good news about the previous little problems that now are all solved and the session was perfect in terms of reliability. 

 

Not so on power target. The mapper managed to reach bit more of 223hp, (194atw), but said that it haves a bit of surge at about 3700rpm (i hear "something" too and ask him, and he confirmed that its surge), and have boost fluctuations in high rpm range. 

 

He said that feels like the engine is not coping with the boost at high rpm (1.2bar) and thinks the intercooler setup is very inneficient and restrictive. 

 

We have a iat rise of 25degC on a 10seg pull, reaching 50 or even 55degC and the power marks were going down slowly throught the session. So next step is upgrading the inlet cooling. 

 

He said that engine is claiming for less advance than normal on high rpm, about 2deg, and the high inlet temps make him set a protective retard function based on inlet temps to retard up to 3deg more. 

 

But this is not definitely a solution. Egts will be a problem to take in account too. 

 

First plan was fitting a larger/thicker air-air IC, but then the watercooler idea came across, and we are thinking on fitting a T16 watercooler+radiator. They seem to be the same as 605/xm 2.5td watercooler system and seems to be a easy fit. 

 

Someone have tried this cooler and know if they suit the power target? 

 

I leave a dyno plot. Thicker line is a standard cam timing pull, and the other a slightly retarded cam timing pull. 

 

Thanks for all. 

 

IMG_20210219_172421.jpg

Edited by lahondal
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petert

Why don’t you make a custom rad/intercooler, rather than trying to squeeze in the T16 unit? You definitely need to lower the bottom of the radiator, if you’re to have enough cooling efficiency. Also, does the oil cooler need to be that big and up where it is? If it’s dry sumped it can be significantly smaller. Mine is down near the bumper and horizontal. Following with interest.

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lahondal

Well, the plan is to use the 605 rad because seems to be almost a perfect fit in place on the actual intercooler, very low and wide profile and with the correct in/out places and size. Leave a pic. 

 

The watercooler thought in the t16 unit, but there are loads of ebay units that will fit but im unsure of the performance they brings. Sure better than actual setup but dont to buy twice but avoid to throw 1000euro on watercooler setup. Anyone tried one of these? 

 

Also we are thinking on change the inlet manifold too. Plan is have a lateral TB instead of the rad-pointing TB that we have now. I have a pair of gti manifolds and a aluminium turbo manifold to chop and go custom, but dont know what to do. 

 

41bOgrqcTGL._AC_.jpg

s-l300.jpg

7932477797331603870.JPG

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welshpug

focus ST or Landrover freelander 2 intercooler looks like it would fit, they are efficient oem cores  (same part!) 

 

bigger is not always better, especially with cheap far eastern sourced cores, a well specified oem core can be vastly superior and lighter.

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welshpug

Your intercooler piping look horrendously long also, you could easily lose half the length!  

 

and lastly you have no ducting/shroud to direct air through the core, air/liquid will take path of least resistance, going around the core instead of through it.

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lahondal
3 hours ago, welshpug said:

focus ST or Landrover freelander 2 intercooler looks like it would fit, they are efficient oem cores  (same part!) 

 

bigger is not always better, especially with cheap far eastern sourced cores, a well specified oem core can be vastly superior and lighter.

Thinking on fit a stage2 airtec focus st intercooler and keep it simple. 

 

No idea how to cut the length of the ic piping with the cooler in the same place... 

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SRDT
On 2/20/2021 at 4:52 PM, lahondal said:

we are thinking on fitting a T16 watercooler+radiator. They seem to be the same as 605/xm 2.5td watercooler system and seems to be a easy fit.

I have been told that they are not exactly the same, and not just because of the "TURBO" plastic thing.

It shouldn't be a problem when you are making a custom engine anyway.

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