998 KP35
Turbo Mini Forums

Bit of quick advice needed. I have fitted a small kp35 turbo from the Renault 1500 diesel range with the aim of good low end boost on a stock 998 . The first start up on axle stands revealed huge boost levels with a couple of throttle pumps and without load, which is a bit of a supprise and maybe a concern that the turbo could easily overspeed. What is more of a problem and not something I considered, is that the wastage actuator opens at around 1.5 -2 bar ( way too high for my engine). Is this about right for diesels? The real question, any recomendations for cost effective actuators that operate at around 0.5bar, with the idea of bleeding off to raise boost levels. Ebay seems to have stock actuators with no pressure spec or £100 plus actuators. Is .5bar maybe not popular? I don't want to butcher my T3, but are these actuators available still?

Edited by Jd24-7 on 2nd Mar, 2021.

I’ve a stock T3 actuator you can have for £5 + post if it’s any use to you?
Though the turbo sounds like it’s far from suited if you’re seeing boost from simply revving it without load.

Phil.

WWW.TURBO-MINI.COM

As the KP35 run actuator pressure, i'd either change it out for one like Phil is offering, or see if lowering the pre-load works. This turbo is designed to spool quickly on a low revving 1.4TDi.

Little bit of a belated update.
This 998 was only ever meant to be used to get the car back up and running whilst I rebuilt its old 1275 turbo. I put in with all the original t3 setup and ran it. The t3 being completely wrong for the 998, only served to let me sort the plumbing and get all the old carb and fueling working again. (20years ina a shed) what did work at well was realising that even a slow mini is fun to drive.
Unfortunately, the engineer in me started tinkering and I ended up with this tiny kp35 turbo fitted and producing good results. The downside was fairly uncontrolled boost which I discovered was down to the wastegate being unable to relieve enough exhaust. Even with the gate wired fully open I could get well over a Bar when flat out.
So, to today's little update. I added a remote wastegate to the exhaust manifold and I now have very good control and I am able to keep boost at 0.6-0.7 bar which the engine seems happy with.. No engine mods, so I am pushing against a wall of 998 cylinder head!
This is never going to make massive power, but it does make the car a lot of fun to drive around town and the local dual tracks /roundabouts . I've covered about 1000miles and most of those miles have been thrashed miles, so I am quite happy with how it has held up. I haven't set the ignition up, I have 35 degrees off boost and about 20 everywhere else. I haven't strobed it to see if that is in any way correct, but it runs OK for now.. same with the fuel, std mg turbo setup
This is clearly not set up or dynoed, so for a bench mark, I use a friend in a clio 2.0. This supprised me massively, as I kept up (just) up to about 60mph on flatish stretches of road between roundabouts. The clio could probably do this all day, whereas the mini would probably fail in a cloud of metal and smoke !!

So the budget so far.
998 £150
Chineese turbo £65
Homemade manifold parts and exhaust mods <£100 not 100%sure what I paid.
Dump valve, Ebay special £55
Hoses and stuff £50
Carb and plenum etc not sure, I paid £25, 25 years ago
Megajolt Not sure , bought it 7 or 8 years ago
Fuel pump - used £10- £20?? Bosch similar to 044


Would I do it again? - yes
Same turbo?- maybe, they are cheap and compact, but there is likely a better choice.
Is it worth turboing a 998? Oh yes, why would you not
Value for money? Definitely

As a sideline, vinyl seats in this weather are dangerous!!!

Sounds like a lot of fun!

Seem to remember people on here drilling out the wastegate hole to help against overboosting/boostspikes(?) not sure if that would in your application though.

Dazed and Confused....

It's quite possible that some fettling of the wastegate orifice would achieve the same result, but I went with the external gate as it seemed to offer the best chance of success and minimal risk. As a downside, its a bit of a pain to fit, exhaust in/out etc, but function wise it is spot on.

i send you a message Jd24-7
I have exactly the same problem(boost problem)
KP35 turbo,stock998 ,dhla carb and side mount turbo with intercooler.
maybe my turbo is slightly different but with wastegate wire open the car only hit 0.3 bar