Nistune Forums

chris might want to try zipping it. or email and I'll upload and link to it

MichaS14a wrote:Sorry but I don't see an attachement.

all fixed... zipped a doc file... added a second one but not as effective as it has no hole in it and looks harder to adjust.. let me know how all you DIY'ers go out there the ore the merrier...

chris

Ahhh, thank you @chris!
Now I can download the attachement.

But I have personally no use for it as I already use an Apexi AVC-R as boost controller (for more than 2 years now) with good results.

all good just a little bit of fun if one of your mates gets into turbo's..

Will get them bitten by the boost bug...

I think there is a big field of application for this informations in any case.
Thank you for publishing this!

alright now back to my car as I am back at work...

I am seing a dip in the top end boost it is peaking at about 16psi... and falling back to 14 in second gear...

so in the top end I am pushing 100%pwm so I will get the 65 value drop it down so there is less bleed in the middle section of the map like 40 %... then crank up on the spring pressure a bit in the "T" to bring the boost back up.. This should then help the wastegate close back up in the top end by supplying less air throught the ball / spring and being able to vent the same amount..

well I got better results... just tweaking the boost maps..

I have to bleed a little more on the mid section and it is working well however you have to keep the car well loaded I will have to get out some 25ltr containers... although I might get a dyno for the day.. as it is safer..

I am more than happy with the results and will pst some picks of the install / setup.

The new bttom end tourque actually gave me 50 ks more out of a tank... who says boost control cant give economy.. dont wory about leaning up the light cruise...

going to go and get some dyno time to map the boost again under the same conditions so I can do a comparison..

also doing some other things just to see if there is a difference before the dyno..

ported to 3"





ported with sought of surge cover but the slot is just infront of impeller blades..





What do you think ? you cant see the surge slot but it is about 1mm..



I can swap from solid no 1 to ported.. to see if there is a difference... without taking the turbo off ....

also 550's will go on and also z32 just for safety, last time I was pushing the duty cycle a little..

I suspect the ported cover may make a bit of difference but it's unlikely your surge ports will cos there's no way that compressor will approach surge on a SR20.

10 points for being willing to experiment though. More power to you Chris!

PL

yeah I am kind of guessing witht he surge slot... however it is different.. I was looking at a HKS gtrs i think turbo.. it had a bolt on surge cover.. doing a bit of research...

The surge slot is there to be able to unload the compreessor wheel should the engine not use as much air as the turbo is supplying.. it does this by being able to recirculate the air from the compression side to the intake side of the compressor wheel at light loads.. The stalling effect of the compressor wheel is like a kangaroo hop.. it costs you a bit in compressor efficiency though but only in low boost at light loads..



it is simple as soon as there is back pressure on the blades it gives the air a path to escape without stalling the compresor..

As you can see the surge slots are below the impeller blades..

I moved the surge slot infront because I am not interested in preventing surge... but more interested in more top end and hoping the the slot will work like a venturi.. Driving that car with the gtrs turbo I was very impressed with the top end boost.. and the only thing that I can think of is the the surge slot is working like a venturi at high rpm allowing more flow at less of a restriction..

reason is that as the inlet air speed increases the way in which the compressor blade pushes the air to the walls and drags it in goes further inside the turbo so no longer pushes the air through the recirc slot..

like any venturi if you have a flow passing a slot especially when it changes down in diameter you can make a venturi so in theory it should work..

Anyway time will tell, but my thoughts are that it wont make all that much of a difference on such a small turbo.. but hey lets see..

I can tell you why the GTRS has more top end - it runs a 71mm comp wheel instead of the 60mm wheel found on the T28.

PL

ah ok, it just was so different.. it built boost slowly then once it got up over zero it snapped to 15psi like no tomorrow wasnt feeling like lag.. maybe it was the cams in the car i dont know..

got a little bored so decided to play around a little more with the compressor cover.





as you can tell I was really bored... Honing the casing is not fun.. got rid of all the sand / moulding / caseing marks.. anyone ever tried that ? how did you do it ?

well the compressor housing is in.. I have taken it for a little spin.. seems a little bit stronger but really nothing to write home about.. I changed over to braided lines and also now running 3" all the way to the turbo accept for the standard 60mm AFM.. which will go to z32 eventually. The plan i to go to work on one for a week then change over to the other for the week and evaluate...

1. was it a waste of time...
2. which was better the one with holes or without holes..
3. is the standard one good enough with the billet adapter..