My Winter Project

[Prof]

Ok - time for a progress update on this !
 
I was never happy with the way the turbo spooled after the wastegate was ported - it stopped the turbo overspooling - but it also robbed the car of a lot of acceleration and mid range power.
 
I also had that oil drain to sort out, as the OMP adaptor that lets me run 2 stroke in the oil injectors meant the stock oil drain could not be used any more. I\'d jerry rigged that with a bit of silicon pipe, but it needed a proper job doing on it.
 
So Oil drain was swapped for a bit of thick (1/2") braided line and some nice ally t04 flanges.
 
Also got an HKS actuator to replace the stock one, who\'s spring was weak and being pushed open by the exhaust gases on acting on the flapper. I had to cut the old actuator off the bracket, as the supplied one wasn\'t going to locate the actuator arm and turnbuckle in the right place. So after some drilling, cutting my arms to shreds getting up under the car, the turbo was out - actuator changed and back in again.
 
Results are looking good - new turbo setup makes 8.8psi just on spring (boost controller off) and holds it rock solid. With a bit of boost controller (15% gain) it makes 11 psi and again it\'s solid - so that\'s my low setting done - just needs tweaking on the gain a bit and the start gain. Then I need to revisit the fuelling maps in the Emanage before I go set the high setting (14 psi) - at the moment the are set to just bog out so that I don\'t push the car too hard.
 
The observant among you will notice the extra metal at the back of the turbo - a modifcation that Rotechniks made to allow more room for the wastegate flapper to open - and it works really well
 
Here\'s a few pics ...

[grinder]

looking good dave

[TiddlesRX7]

Yep, what Stu said. Keep up the good work mate.

[antnicuk]

did Rotechnics make the plate or get it made or is it an after market bit.  I machined a well in the back of my stock plate to allow it to open more.  I dont get boost spike but the poor little compressor cant create enough boost past 5k rpm

I know you have probably posted this somewhere but what is the spec of your turbo?  does it have enough flow ? or does it tail off?

[Prof]

did Rotechnics make the plate or get it made or is it an after market bit. I machined a well in the back of my stock plate to allow it to open more. I dont get boost spike but the poor little compressor cant create enough boost past 5k rpm
 
I know you have probably posted this somewhere but what is the spec of your turbo? does it have enough flow ? or does it tail off?

It\'s the back off an old turbo - it spaces the real back plate another 10mm or so off the exhaust housing - so the flapper can open as far as the wastegate can push it - there is also a nobble on the outside that might need filing down, but when I checked clearance, the wastegate can\'t move the flapper arm that far anyway. It means that a lot more gas can clear through the wastegate.
 
The turbo starts to spool up from about 3800 now (was more like 4000 before) and is on full boost by 4500 RPM - it hold this to past 7000 when on spring only - and from initial testing it seems to hold on the low setting on my boost controller - which takes it to about 11.5 psi.
 
The old wastegate couldn\'t hold the flapper shut, so it was just bleeding off the boost - if I gunned it really hard it would make maybe 13 psi but would drop off really quickly. It would hold 7-8 psi ok. This new wastegate has an adjustable spring rate from 7.5-15 psi, (adjusted by rotating the turnbuckle on the shaft) so I\'ve set it on the low end as I\'m using a boost controller. It seems to be set around 8.8 psi.
 
The rear section of the turbo is a standard HT18, but with the back plate modification and ported wastegates (pretty much taken to the max they can be).  The centre section has 360 journal bearings and was balanced. The front section is a T04B with an a/r .70 compressor housing with 3" inlet and outlet the same as the standard HT18 compressor. It flows a lot more air, but is maybe 500-1000 rpm later in the rev range and holds to redline easily. It\'s easily twice the size of the standard turbo on the front :Giggle.
 
I am still using the stock manifold - but I\'ve got a spare and may experiment with trying to port that out a little - at the very least just to tidy up the sharper edges and make it flow more smoothly. There isn\'t a great deal of metal spare in these anyway and they can be prone to cracking.
 
I wasn\'t looking to make a 500 bhp car, so the turbo seems ideal for my target of 300 at the wheels.

[antnicuk]

I am wondering if my boost is dropping off due to the actuator rather than the compressor not keeping up. I\'m still using the original.  Is your engine ported? if so is it inlet and exhaust ports?

I am using a boost controller which should keeping the wastegate shut if the boost isnt what its set to but if the spring is weak i suppose the exhaust gasses could be pusing it open still.

By 6k rpm i\'m down to 4 - 5 psi. I thought this was down to the comp housing being too small. I have no lag, i\'m on full boost by 3k which peaks at 9 psi but soon drops off.

Who built your turbo and where did you get your actuator?

[Prof]

Could be a week actuator - that bleed off was the exact same symptoms I had. Since I knew the turbo delivered a lot more with a more restrictive wastegate, I knew the compressor wasn\'t giving out.  I suspect that when you port the wastegates, you are allowing a much larger area of flap to be acted on by your exhaust gases, so the spring in the actuator is having to keep the flap shut against more force.  The boost controller works by not allowing the boost to go to the actuator, but can\'t help to keep it shut - that\'s all down to the spring.
 
The only way around that problem other than use a stiffer spring would be to use a 4 port solenoid and a dual port actuator.  That way you could direct boost pressure against the diaphragm in the actuator and assist the spring until you wanted to open it - then you switch over the boost to the other port and it will open very quickly.
 
I was considering that as the next option, but the HKS actuator appears to be man enough for the job.  I got mine from the US - as RHD Japan prices have gone up big time !  Was about £70 and £12 through customs.  Just google for HKS actuator upgrade kit (FC3S).
 
I got the turbo off an outfit in the US - was about £300 delivered - but they didn\'t port the wastegates and there was play on the shaft, so it went off to be rebuilt by Turbo Technics I believe - they did the thrust bearings, seals, porting and used my old turbine wheel and shaft which were fine and then re balanced the whole assembly.

[pdtaylor18]

Good work Dave,interesting stuff as I have yet to see what my hybrid will deliver, same for the exhaust side but mine has a TO4E compressor and upgraded actuator but no idea on the spring rate. Seems a lot of money went into your turbo from start to finish.
I have two spare manifolds that i might play with but as you say they crack really bad,might even get mine repaired but to be honest I am waiting for a aftermarket one to appear at a good price. They do the stainless ones but for the T4 turbo and i have yet to see an adapter that converts from T4 to the bolt pattern on our turbos. I do have an adpater but it does not fit the 7\'s exhaust pattern although I thought it was based on the T3?. Sometimes they do come up in Japan but its just another expence and not really sure how much to gain.
I have taken the turbo on and off at least 6 times so i am quite versed to the knack now, Where did you buy the oil flanges from? just what i need for not only the drain but the feed as well.

[Prof]

The flanges came from Level Zero Motorsports:
 
http://www.levelzeromotorsports.com/store/product_info.php?cPath=23&products_id=48&osCsid=c10c06465e874a0e41e821a6af70f82f
 
I got the brass fittings from a generic plumbing outlet - but one thing I would say - the ally and brass expand at different rates, and the oil will track round the threads - even though they are supposed to be tapered fit.  A little bit of gasket seal or something will be fine - that particular spot on the turbo doesn\'t get as hot as the exhaust housing - so anything that will resist 150 degress C should be ok.