R5 - 172 Turbo Project **Updated**

Quote:

---

Originally Posted by Scoff

PS looking again at ashy's plot I'd say some inlet cam advance would help to bring midrange up a bit more and make peak HP a bit lower down. Maybe a good thing if it's predominantly a road and track car.

---

I keep trying to persuade him to wire in the solenoid but hes having non of it.

It's an interesting comparison Ashy's vs my Trophy, when Scoff was mapping it I popped up for a catch up with both him and Ashy and I was shocked when it made exactly the same as mine did at 1 bar, we both made 340bhp ish. I've always been led to believe that the bigger the turbo the less boost required for more power :rolleyes: I must admit that the GT28 .86 housing flows exactly the same as the GT30 .63 housing so that could account for some of it but I honestly expected the 60mm turbine wheel and the tubular manifold to prove it's worth on Ashy's.

As it's all unfolding I probably should of just stuck with my logg mani and fitted a stronger box, admittedly Ashys seems to flow better at the top end as like Tutuur points out mine starts to drop off whilst Ashys was begging for more boost :D It makes me wonder about dyno tuning as Paul @ RStuning has built several megane forged lumps on GTX3071/76 and there all making 450bhp @ 1.5 bar which using Scoffs conversion would make it a 180 bhp N/a lump which is unlikely due to the lower comp.

Matt, Andrew Cooke had me looking at Evo cams (kelfords) and comparing things like where peak power came in, what rpm was needed, how crap lower rpm was and idling issues, overlap etc.... we both came to the same conclusion that what I'm using was the best compromie. I have a spare set you can use but, obviously I'm using VVT and your not so your limited on the inlet cam choice. I would probably get a 182/197 head.

Mine and Ashy's for easy comparison.

http://i274.photobucket.com/albums/j...ps35c50f01.jpg

http://i274.photobucket.com/albums/j...rophysep10.jpg

----
but I honestly expected the 60mm turbine wheel and the tubular manifold to prove it's worth on Ashy's.
----

Like I say steve, you can't magic up airflow from thin air :) At those power levels the smaller turbo in your case is still flowing adequate, so there is next to no advantage from ashy's larger turbine, etc. Raise the boost to 1.7 bar and it's a different story.

Compression ratio doesn't affect matters as much as you might think. For the rule of thumb to work we ignore the drop in power which might happen at NA because of the low CR.

More like 190hp at NA for those 225 engines if they're making 450hp at 1.5 bar. Nothing is 100% efficient :) I guess they have cams in them.

Yeah they have custom catcams to help them flow a bit better.

He recently did a rs250 forged with stock cams and a gtx28 turbo on a tubular manifold and it made 399bhp and 360lb/ft at 1.4 bar which I suppose is quite comparable with Ashy's power wise but shows that the slightly restrictive cams and smaller turbine wheel are helping the torque

That was the most we could get out of my set up, any more increase in boost just saw the EGT's and and Torque rising but no increase in BHP

Went for a drive tonight, pulling up a hill in third, full boost went for 4th, foot down then nothing, lost all drive.... :eek:

Managed to free wheel into a nearby industrial estate and pull over. Selected gears fine, no loud bang or noises, engine running sweet... Assumed the worst, diff / gearbox failure :cry:

A-framed her home, had a quick look underneath and found it had destroyed a CV joint on the passenger side :eek:

https://www.rtoc.org/files/Technical%...ment/image.jpg

Funny how its killed the VW cv not the Gtt one!

Oh we'll least the engine doesn't need to come back out :agree:

Impressive..... and annoying lol

ohh err..... surprised like you said the vw side let go:eek:

i dont think anybody else who is running this set up has broken the inner vw cv before the outer:scratch:

maybe its just bad luck that the drive shafts inner cv were worn/weakened before they were modded to fit the 5 :crap:

Quote:

---

Originally Posted by Tony Walker

Impressive..... and annoying lol

---

Think that's hit the nail right on the head..........

Or maybe it's time to turn the boost down LOL :laugh:

Noooooooooooooo:wasntme:

the bolts on the inner are quite common for backing off. maybe a couple of bolts came loose and bang. make sure the next ones are lock tighted.

Quote:

---

Originally Posted by Tony Walker

the bolts on the inner are quite common for backing off. maybe a couple of bolts came loose and bang. make sure the next ones are lock tighted.

---

Yeah I've had that before on my old passat, however these had done less than 100 miles since putting the engine back in :crap:

Ash!

What injectors are you running? By the looks of it they are 630cc deka's?
I've been having trouble idling with them.

What are your pw's at idle? Or don't you have wari on your laptop yourself?

Cheers

Yes mate 630cc Siemens Deka Injectors, my idle is fine... Duno what the PW is at idle, I use a DTA ecu and the software is on my other laptop... I'll check at the weekend :)

Thanks mate! Everywhere i read people are having no problems with the 630cc's but i'm idling around 11:1 with 1.3ms which is about lowest it will go without going very unlinear.

hi mate,

did you have a look? i guess you're running sequential too btw?

cheers!

New poster! (less than 10 posts)

Superb read Ashy!

What seats are they?

Quote:

---

Originally Posted by Ian M

What seats are they?

---

Post 268 ;)

New poster! (less than 10 posts)

Sorry missed that!

Maybe i missed it but how did you seal up the oil channels in the cam?

I'm in the process of fitting 172 cams to a 225 engine so need to block the holes.

He made some dowels and also blocked up the hole in the bolt.;)

How's the car mate, still going strong?

I'm in the process of building a 225 engine into my 197 and thought about this thread, convinced me into going big turbo instead of bodgering with an hybrid td04 shitcan