RS2 - a new lease of life

[AndyP]

I think we must have entered a rift in the space time continuum, first Jamo was agreeing with Dimitri, and now Vas, whats going on??

[Error404]

[A80Avant]

I have no idea what prj is writing. Happier that way

[Ross]

Haha, i saw this earlier and decided I'd reply later. See where it was going...

Decisions decisions eh... I've decided to stick with the 3B cam if it's the same as ABY. If I get an ADU cam at some point I'll maybe make the swap but sounds like it's not such a comprismise up top to not have it. Besides, JP has already timed it up, shame I didn't check out the cam lift before - just assumed it was 7A.

I think it's shocking that Dialynx sold 3B cams as "performance" and of course kept the RS2 cams in the deal :corey:

I've already decided on #6 hotside as I'm after a 'street' setup rather than raw power. I don't want to lose sight of that - I was close to going down the power route, but originally I wanted slightly earlier power and/or ar least better off-boost driveability.

I was concerned this wouldn't make my goal of 400hp, but seeing Dmitri's base map on a turbo with the same hotside come in at ~400hp made that decision final. I've gone for a different coldside, bit of a gamble but I'm hoping it pays off with peak torque around 3800rpm in 3rd and good early, progressive spool and still ~400-410hp.

[macspring]

I think we must have entered a rift in the space time continuum, first Jamo was agreeing with Dimitri, and now Vas, whats going on??

Well observed.

[macspring]

Ross,

Based on the information available to your right now, when you you reckon your turbo will kick in ?

Perennial question I know, but still interested.

Thanks.

[Ross]

Today i got a little distracted, seeing as I couldn't continue running in the engine I took things apart instead.

Comparison of old vs new K26/7:

The hotside is a K26 #6 on both. The old wheel is 55.5mm, and cut back blades, vs 55.0mm on the new. This should help spool a little.



The coldside is where the difference is... wheel is huge in comparison!



...and fitted.





Do two bodge's make a right? The old set-up measured boost for the WGFV from this nipple tapped onto the inlet tract. Surprisingly, it's airtight and threaded, so a nut and lots of PFTE later it's blanked off. Anyone have a spare plastic intake tube



I wish I could have got the images of me lifting the downpipe with an old seatbelt whilst Pete levered the turbo onto the EM with a big screw driver... oh, and reclocking a turbo is ALOT easier when done before fitting the turbo

Next job, obviously, is to put everything back together, and get out and see if this thing starts making boost before 4k. Need to sort the linkage again as it's come loose, change the oil and replace the coolant that is now all over my garage floor. About 1/3 of it ended up in the bucket i placed underneath the turbo

[newsh]

I think I've got a couple of tubes here Ross, I'll have a look.

[Ross]

Cheers Newsh, if you have one spare I'll take it. part-ex on the old one if you like

David - my hope is for max boost ~3800rpm in 3rd vs current 4000rpm. The hotside exducer size is similar but does not have cut-back turbine blades which will aid spool, and hopefully is a little more efficient. As the old one made 365-375 I would be concerned, except Dmitri's current K26/7 uses the same. His log (attached) from an ealy map (i.e. not optimised) shows 1.9bar at ~3900 and 0.5bar+ at ~3000 with 1.55bar at the redline. That will do me fine.

That said... I'm happy with the massively improved response and 'grunt' off-boost. It really has transformed the car's round-town driving and that has to be to the credit of JP's head work.

Initially I was concerned about making peak boost 500rpm earlier, about 3500rpm was my goal. What I've learned is that actually i want is better round-town driveability which means better off-boost performance and a more progressive (earlier) spool to get rid of the 3-3500 'dead spot'. Even if peak boost is at 4k like my current turbo, if it's coming in from 3k combined with the improvements from head porting I'll be very happy. Currently I don't see over 0.5bar+ until >3500rpm; Dmitri's log shows 0.5 by 3000rpm.

I have gone for a different compressor wheel, a bit of a gamble but in theory it is better. I couldn't say no - it was the pioneering side of me that decided to try something unproven

I was hoping to have a bit of a play today but I had a set-back yesterday when i checked torque on the cam cap studs and two were knackered. Hoping to replace these and get it running again in the next few days.

[Ross]

I've had a few set-backs here... a minor oil leak on the turbo oil inlet (again!), coolant leak, boost leak and then a 'dead' boost gauge... combined with no spare time

I had to replace the oil inlet gasket again - I used a new one last time, but there was one tiny chunk of the old one stuck to it that had gone unnoticed. I cleaned up the flange with a blade and this time no leak Air leak was a couple of worn jubilee clips that I finally got round to replacing, and the boost gauge was 'dead' because the line from the IM to the ECU had a kink in it so no air was getting through

I'm not sure on the coolant leak - I can't see anything leaking, even an hour after parking the car after a run. But there's always a small puddle after a few hours One concern - I'm going to have another go at ensuring it's bled properly - sounds like a kettle is boiling in the pipe to the top of the rad for 5-10 minutes after shut down, and there is alot of pressure to release, would have normally related this to a potential HG issue

Continuing to put miles on it this week... I gave it a bit more stick, up to about 4200 rpm with the WGFV in so i was seeing a bit more boost :mischeif: I don't think I can really evaluate properly till it's mapped but I think it is safe to say the 3-3.5k 'dead spot' is something I will have to live with I wasn't WOT but felt it come alive at 3500rpm and at 4k it was pulling really hard. 4th gear I saw close to 1.5bar and backed off, revs were at 3700rpm, decided playtime was over.

Inially I was a bit disappointed to see no improvement in response, but I don't think it's worse than the old K26/7, and if it gives me an extra 50hp on the top end then I'll be happy... I've got to get more miles, a 3" downpipe and map is required first :mischeif:

[A80Avant]

Ross, a bit of tweaking of the throttle response to the boost curve will allow for some improvement on the dead spot. Motronic easily can adjust to give more boost on part throttle

[tscheel]

I'm not sure on the coolant leak - I can't see anything leaking, even an hour after parking the car after a run. But there's always a small puddle after a few hours

I had exactly that on my 7A - it was the water pump bearing that was gone after only 3 years of service. I was being too cheap when I prepared the engine for installation - cheap part. Now it has a Febi pump.

One concern - I'm going to have another go at ensuring it's bled properly - sounds like a kettle is boiling in the pipe to the top of the rad for 5-10 minutes after shut down, and there is alot of pressure to release, would have normally related this to a potential HG issue

[Jamo]

Rs2 water pump is no cheap part oem / tps only last time I bought one
Good work Ross I love it when I see on Facebook your wife moaning about you working on the car means you have the eye of the tiger back!

[prj]

You should be more satisfied with the performance once it is mapped :mischeif:

[macspring]

Thanks for feedback Ross, but as Dimitri says, once it's mapped will tell the full tale.

I'm happy to wait until then.

Kind regards.