219 replies to this topic

[Soop]

Nice work dude.
Good to see some proper modifications going on!

[acres]

Thanks Soop.

So fired her up last night. Apart from a chronic boost leak and the primary up pipe developing a nice crack, so far so good Build up on primary felt a bit more sluggish but that's to be expected with the leaks but vod was very similar to the stock turbos. That's good news to me as the concern was that it would be worse with the larger journal bearing turbos. Power felt very similar to the vf turbos but again the boost leak is quite bad so this should improve. Peak boost from secondary was close to 1.2 bar. Overall I'm very pleased thus far and feel that there is alot of potential from this setup.

I haven't taken any pics of the engine bay yet but the pipework that loops around from the primary is a very tight squeeze. It is actually wedged against the strut tower.

[Alex]

Nothing a convincing massage from a BFH can't fix.

What up pipes are you using?


(please don't say stock!)

[acres]

Exhaust is stock bar a 3" catback and 3" straight through muffler.
Engine bay was too hot to be investigating where the boost leak was coming from but I'm fairly certain I know which clamp it is. I pulled a dodgy act on one of them hoping it would work it out. I guess it didn't.

[alexGT]

you will get FAR better gains with a 3" dump. the stock is very restrictive.

[acres]

I would think that 3" dumps might be overkill for the twins? but yes the rest of the exhaust will be getting done too. The TMIC is a fair restriction at the moment too. It's intake pipes are a much smaller diameter than that of the compressor outlet.

[alexGT]

I would think that 3" dumps might be overkill for the twins? but yes the rest of the exhaust will be getting done too. The TMIC is a fair restriction at the moment too. It's intake pipes are a much smaller diameter than that of the compressor outlet.

i think the common twin dump setup is 2.5 off the pri and 3" off the secondary. with the secondary size that you have i'd suggest bigger = better. TD04 with 3" dump provides BIG gains on a single turbo barely modified wrx.

[Billsy]

you will get FAR better gains with a 3" dump. the stock is very restrictive.

not really, the std dumps arent overly restrictive. atleast not upto 188kw.

also most tt dumps ive seen are 2.5 on both, there is no benefit in going larger at all. and it makes it harder to fit

[BigWillieStyles]

not really, the std dumps arent overly restrictive. atleast not upto 188kw.

also most tt dumps ive seen are 2.5 on both, there is no benefit in going larger at all. and it makes it harder to fit

Would the larger 26/27 turbos benefit from 3inch?

[acres]

Would the larger 26/27 turbos benefit from 3inch?

Larger compared to what? The 26 has a smaller A/R in comparison to the 14 and 18. None of the VF turbos available are really bigger or smaller though, it's just that some have slightly differing specs on their wheels and different AR ratios. This doesn't really effect peak flow so much but rather alter their response/performance throughout the powerband.

Got home late from work last night but had a quick fiddle with the car and took it for a drive to the servo to get fuel. No more boost leaks - couple of the clamps just weren't tight enough. Just drove it very casually and kept it on primary and I must say I'm very pleased now. Starts producing boost at about 1800rpm and builds up pretty quickly. Feels to be delivering the same power as the VF18 but at a much lower boost - about .4 bar as opposed to .6 bar. And the intake noise! Very cool. Not sure if its the larger turbo, the intake pipe or a combination of both but whatever it is, it makes me smile.
Downside was on the last stretch of road before getting home I thought I would open her up and see how she went. Secondary never came online car surged and staggered forward with zero power. I backed off waited for it to kick back to primary and it was fine again. Did a quick investigation when I got back and the IC valve is working fine, no codes were thrown and the ecv had definitely opened when it was supposed to. Ideas?

[zanzarah]

Larger compared to what? The 26 has a smaller A/R in comparison to the 14 and 18. None of the VF turbos available are really bigger or smaller though, it's just that some have slightly differing specs on their wheels and different AR ratios. This doesn't really effect peak flow so much but rather alter their response/performance throughout the powerband.

Got home late from work last night but had a quick fiddle with the car and took it for a drive to the servo to get fuel. No more boost leaks - couple of the clamps just weren't tight enough. Just drove it very casually and kept it on primary and I must say I'm very pleased now. Starts producing boost at about 1800rpm and builds up pretty quickly. Feels to be delivering the same power as the VF18 but at a much lower boost - about .4 bar as opposed to .6 bar. And the intake noise! Very cool. Not sure if its the larger turbo, the intake pipe or a combination of both but whatever it is, it makes me smile.
Downside was on the last stretch of road before getting home I thought I would open her up and see how she went. Secondary never came online car surged and staggered forward with zero power. I backed off waited for it to kick back to primary and it was fine again. Did a quick investigation when I got back and the IC valve is working fine, no codes were thrown and the ecv had definitely opened when it was supposed to. Ideas?

The ECV may have excessive pretension/lock down! May need to loosen it back? (billsy)

[acres]

The ECV may have excessive pretension/lock down! May need to loosen it back? (billsy)

Possibly. It definately opened though or at least partially as I could hear the difference in the exhaust. When I took it for a drive the first night I started it, it had no trouble getting to secondary. Maybe it jammed halfway open though. I'll check out tonight.

[acres]

Scored the night off work and got home early yesterday arvo so I made a thorough investigation of what was going on. Put the car into diagnostic mode and discovered that the ECV and IC valve were both operating corrrectly, all the solenoids were clicking and everything seemed to be working properly in general. So I pulled the TMIC off to check the pipework and make sure the welds and rubber hoses were holding up. After removing it I realised what the problem was. This pipe was too short so there wasn't enough rubber extending over the pipe to get a good seal.


So as you can see I have cut a 15mm extension from a bit of left over pipe, ground back the paint and welded them together. I gave the pipe another couple of coats of paint let it dry for 20mins and then baked it in the oven for another 20min. Now there is plenty of pipe to clamp too and enough rubber to create a good strong seal. I also replaced a cloth collar I made for the primary IC intake pipe and replaced it with a better, rubber collar. (It wasn't leaking as far as I can tell but the rubber is more reliable). Also the rubber hose used to connect the secondary's bypass valve to the adaptor on the pipe pictured above had been almost blasted off. I fitted a small clamp to this too. (I never bothered fitting a clamp to this in the first place as it is 19mm hose stretched over approx. 24mm pipe and was on incredibly tight anyway).
So I fitted it all back up, let her idle up to operating temp and reset the ecu again. Went for a nice casual drive for 5 min keeping off boost while I let the ecu settle in before I opened her up on a nice stretch of road. And, well a picture tells a thousand words.....



For those that are imperial minded that translates to roughly 30.57 psi of peak boost!!! Although I doubt the accuracy of this reading as I have noticed that the boost reading will jump slightly while shifting but none the less this is a massive amount of pressure -> obviously why the clamps weren't holding. I shifted somewhere between 6500 and 7000rpm. The power at this point was well beyond my initial expectations and again that induction noise is just fantastic. The combination of whistling from the larger compressors and the sound of the air rushing through the new intake pipe is awesome particularly once that secondary hits.
Now Im not silly I won't be driving the car at boost levels like this without further mods as obviously something will pop. I might try and get that wastgate actuator for the secondary back on somehow as this will aid in controlling the boost. I also definately need to do something about the exhaust leak in the primaries up pipe. I got under the car while it was unning last night to check the leak and it is quite bad. It will definately be hampering performance of the primary and VOD. Speaking of VOD it is definately no worse with these turbos in fact I would say it has improved slightly. The length of the VOD is the same, the secondary takes the same time to kick in as the VF19, but the drop in power felt like it had reduced.

So overall I couldn't be happier with the results. Once I get around to sorting the rest of the required mods - full exhaust including headers, new ECV, dual core FMIC, passive IC valve (like Billsy's), fuel control (parralell rails & regulator) and a tune to suit - I have every confidence that this setup can deliver truly blistering performance for a TT. Beyond this there are also the capabilities for some aggressive headwork and an extension of the rev limiter. Flow can be easily increased from these hybrids to match the incresed rpm by simply switching out the comp wheels for some larger 15g, 16T, etc. wheels.



Looks completely stock to the untrained eye.



Primary compressor outlet is rotated in the opposite direction from the VF18. Pipe work is wedged under the fuel filter and against the strut tower.

[Dylan]

Nice work mate, good to hear you're pleased with the results - I look forward to reading more about this !

[buzzda]

Good to hear it's all coming together and working nicely. I wouldn't mind seeing this in the flesh when it's all done.

[Billsy]

very encouraging results indeed.
will be very interested to see a overlay of the 2 dyno graphs once tuned, to compare vod and initial boost response.

whats it like to shift into? is the hole left by a 2L trying to spool 2 tdo4's rather massive?

[acres]

Thanks guys, anybody is more than welcome to check it out. Might have to sort out a power run before moving onto the next exercise. I have a graph from not long after I did the initial conversion (about 2 years ago) so would be interesting to see the difference they make on paper, while everything else is still the same.

I haven't really pushed it too hard yet - bit scared of breaking it - just ran it out in 3rd gear so unsure how it will cope shifting into the hole as yet. I'll update though when I have spent a bit more time driving it.

[Soop]

Might be wise to start working on another short motor

[acres]

Took myself on a bit of a solo cruise through springbrook yesterday arvo and gave the car a bit of a rough time to see how the hybrids respond. I am happy to admit I was wrong about initiating pre-spool sooner to help combat the VOD. The ecu has decided to do this itself and is cracking the ecv open at 3000rpm while in 3rd, 4th or 5th gear which with the factory, leaking headers is limiting primary boost to about 1/3 bar. This is having a big effect on primary power. I still think this won't be as big a problem once I knock up the new headers though. While in 2nd gear the ecu is still holding off pre-spool till about 3500rpm which is giving much stronger primary power.
Shifting from 5th to 3rd at 60km/hr - straight into the vod (just over 3500rpm) - isn't the best. It immediately brings the secondary online and you are left with a pretty sluggish build up as it struggles to spool. Power during vod is really no worse than the 18/19 was at this point but it takes untill 5000rpm before the party starts which is a real drag.
What I did find very effective though was when accelerating moderately hard through the gears if I kept the shift points under 3500rpm then the secondary stayed offline and the primary was always on boost. It accelerated very well like this and felt very torquey compared to the old VF18.

Aaron

[tmh983]

very interesting. I'm keen to try and make a one way valve arrangement for the ICV, I reckon that is probably the first place to find improvements in the system.