I need a wastegate desperately!!!!

[maggotcorps]

I am just about to start putting my engine together (944 turbo '87) after taking it apart and porting the head, my wastegate when i took it off was completely seazed, and the problem i have now is getting hold of a wastegate. I've found plenty of dual port wastegates but have absolutely no clue whether this will be suited to my car. What does a dual port wastegate do that a standard one doesn't and would anyone recomend a dual port instead? Somebody told me it would also make the same noise as a dump valve which is definately something i don't want, is this true?

 

[MNUVVR]

A friend of mine has just put a duel port wastegate on his 944 and I can confirm it does not make a psssshhhht sound on deceleration.It has eliminated nearly all of the lag though and the bugger can keep up with me in my 930. Damn him.

 

[Diver944]

The standard wastegate uses a simple spring to keep it closed until a set pressure is reached. When that pressure is reached the wastgate opens and your exhaust pressure bypasses the turbocharger and goes straight down the exhaust pipe

A dual port wastegate also has a spring but it also has a second port that you can use to adjust the pressure at which the wastegate opens giving you a lot more controlability and also a much better way of keeping it shut. The standard wastegate (even a brand new one) starts to open long before you have reached your set boost level. This increases lag and lowers the power output but makes it very gentle to drive. A Dual port will stay shut until your desired pressure is reached so the turbo will spool up much quicker (reduced lag) and can hold a higher level of boost (if you want it to)

Wizard on this forum has a Lindsey Dual Port wastegate for sale at £150 because he has sold his car. IIRC it is less than a year old and I recommend it is a bargain to replace an old and worn wastegate. It will not make any whoosh noises as that is the dump valve, not the wastegate

 

[maggotcorps]

I gotta say, this forum is awesome. Cheers dudes, every question answered. I'm onto wizard now, try and get the waste gate. Cheers.

 

[wizard]

ORIGINAL: Diver944



Wizard on this forum has a Lindsey Dual Port wastegate for sale at £150 because he has sold his car. IIRC it is less than a year old and I recommend it is a bargain to replace an old and worn wastegate. It will not make any whoosh noises as that is the dump valve, not the wastegate

Too right its a bargin for the gains you can achieve!

 

[wizard]

You have mail!

 

[chrisg]

Mr Wizard, if by chance you don't sell the DPW, let me know ! I'll happily take it off you !

 

[sawood12]

DPW all the way - a single port wastegate is costing you at least 20bhp on a standard car. Bear in mind with a DPW you will also need an external boost control system - ranging from £40ish for a Manual Boost Controller (MBC) which is basically a mechanical pressure reducing valve, or an Electronic Boost Controller (EBC) which are £300+ for one worth having. Obviously EBC is the best way to go but is pricy. MBC's work perfectly fine also. You will aslo need chips. I ran my DPW on standard ECU chips for a while and had overboost problems because the boost builds up so quickly and early compared with standard it tricks the ECU into thinking you are about to overboost and retards the timing.

Just to add to Pauls explanation, the single port wastegate has a diaphram exposed to manifold pressure at one side pushing against a spring. The spring is rated according to the boost pressure you want ot achive so when the manifold pressure achives that pressure the wastegate valve is open and dumping exhaust manifold pressure. The problem is that the wastegate valve opens long before you achieve your intended boost pressure because a spring is not an on/off device and will deflect with a lower pressure applied on the diaphram hence increasing turbo lag.

you can get MBC's from Promax and you can run with standard chips if you set you boost pressure to a little below standard pressure - i had mine set to 0.7 bar, but ideally should swap out your chips as your DME has a boost map and if your boost is building at a different rate to the map then it will trick the ECU into thinking something is wrong.

A DPW has the manifold pressure on one side of the diaphram and a second pressure signal on the other side of the diaphram so as the manifold pressure builds you have equal pressure on both sides of the diaphram and the wastegate valve is positively held firmly shut allowing boost pressure to build as quickly as it possibly can and minimising lag. Once the manifold pressure achived your target boost pressure that you've set your boost control device to the pressure remains constant as the manifold pressure increases therefore opening the wastegate valve and regulating the pressure at your set target boost pressure.

Once you've had a DPW you'll never go back.

 

[George Elliott]

You wont go wrong with that DPW imo, - but am I the only one with a MBC which suffers a bit of flatulence at its set point (17psi) in my case.
It would distract a lesser driver[][][]

I may change to an electronic control.
George
944T

 

[sawood12]

I've got an MBC and havn't noticed any problems, though EBC is high up on my list also.

 

[Diver944]

George, when I had my MBC fitted I didn't notice any flatulance at the point of opening [&:]

When I first fitted my EBC I had it mounted to the chassis with rubber washers and I could hear the solenoid clicking on and off like crazy [], Now it is loosely cable tied to a rubber pipe and all is peace and quiet once more []

 

[wizard]

I had the Greddy Profec II - a black art to setup!

I think Matt (Magotcorp) is at the top of the slippery slope!

 

[random hero]

If matts at the top of the slipery slope then i must be stood right next to him !!! Ive got the pro-max bost enhancer already and am planning a chip set / dpw when i can get hold off them. I'm wanting about 260bhp out of my car ,will this do it or what else would i need !!!

 

[wizard]

Have a look at Ricks website, http://www.cannell.co.uk/944%20UK%20League.htm this will give you a good idea of what gains can be achieved. (Scroll down the page a little to see the car type and enhancements made and what gains delivered)

 

[random hero]

Thanks for that ,i will study it properly later on ,i also have to fit a B&B Tri-flow exhaust as well !!

 

[Diver944]

Random, I had a DPW, Guru chips and a MBC and IIRC hit 287 bhp with my smaller 220bhp turbo so you should reach your target easily. My chart is on Ricks table for LIL5766

 

[random hero]

Ideally i was hoping for 280 which looking at the chart looks possible,trouble is once ive got 280 i no doubt will want more like 300 !!!

 

[Diver944]

ORIGINAL: random hero

trouble is once ive got 280 i no doubt will want more like 300 !!!

I see what you mean, earlier on today you wanted 260 and it's already escalated to 280

 

[poprock]

Just seeing that chart makes me want to step out on to the slippery slope "¦ dangerous stuff!

Since we're on the subject of explaining what the bits and bobs of a turbo actually do and why "¦

I have an adjustable single-port wastegate fitted to my 944T "¦ currently with a 10psi spring set. I have a 17psi set in the garage. If I make the change, what effects can I expect?

 

[random hero]

ORIGINAL: Diver944

ORIGINAL: random hero

trouble is once ive got 280 i no doubt will want more like 300 !!!

I see what you mean, earlier on today you wanted 260 and it's already escalated to 280

Its not my fault ,i looked at the cannell list and saw what was possible, but as the car will be used on the road as well as track use i need something thats drivable for every day use !!!