Hello from the UK

1st - 5th gear pull

50 - 100 kph = 4 Seconds
100 - 150 kph = 5 Seconds

4th gear pull

50 - 100 kph = 6 Seconds
100 - 150 kph = 6 Seconds

Well by eye I can see you're quicker from your GPS reading

My figures

16-54 mph= 4 Seconds
54- 103 mph = 10 Seconds

Mikael GPS plot

16-54 mph = 2.5 Seconds
54- 103 mph = 6 Seconds

To be fair that is seriously impressive.

Have som exact numbers here

Mine 2.9 rwd goes (unlightened)

50 - 100 kph = 3.6s
100 - 150 kph = 3.5s
100 - 200 = 9.9s
0 - 100 = 4.5s
0 - 200kph = 14.5

Kryckans 2.9 3d rwd goes (lightened)

50 - 100kph = 3.6s
100 - 150kph = 3.0s
100 - 200kph = 7.7s
0 - 100 5.6s
0 - 200 = 13.3s

But om certain that you would leave us behind with a pull on 4th gear at low speed

Right looks like I need to do another datalog and try and get a 200kph reading. May try as you suggest lifting the rev limit some as I do have a tendancy to hit it rather often. I think the most accurate way I have for timings is still currently from datalogs. I'll added some fomula in excel I think to work out the figures for me. the Zeitronix samples at 67 times per second so I can find out the timing to atleast to one decimal.

Don't feel so bad now as those runs I made had peak boost of 9.7 psi, how much are you running again. Mine is very much even between my friend Twin Turbo running 1bar. I suspect you're running atleast 1.3bar or possibly something more!

I think a single turbo added onto the setup could work well.

Peaks 15psi on both cars, haven´t done any test on higher boost

even more impressive! kudos

Mikael, I'm looking further into the single Turbo route and for me will involve a few changes, mainly cam change, a custom dual I/C and rad setup (will cut out the front crossmember and fit a smaller bar in it's place), obviously manifold & exhaust changes.

However I'm curious as the spec of your GT40 as I'm thinking of either GT35 or GT40 (after seeing you success using it) with a large ish exhaust housing (possibly 0-8 to 1 ar). I'm working on a budget and looking for a decent turbo at a good price.

Regards

Rob

If i remeber correctly it has

Compressor

Inducer 56mm
Exducer 82mm

Turbine

Inducer 72mm
Exducer 62mm

A/R .099

Fabulous, I will keep an eye out for a good deal. Out of interest is yours a roller bearing turbo?

I will be Taxing my Sierra at the end of the month so I'll take her out for a spin and get some datalogs (and blow out some cob webs) with a higher rev limit, I do think power tails off pretty quick though on mine above 6k.

You mentioned the reduced cam over lap is not so good, which is wierd as it's contrary to what I had from my literature. I've not got alot of experience with cam specs but I have similar over lap to standard cam spec. When I order my cam it had a mild duration with greater lift but had a narrower lobe angle and this would have been 111 degrees and I've had this increased to 114 degrees. I found it hard to dial the timing in with this, I think I may look at making an adjustable sprocket, is this something you have done?

Roller bearing is nice but very expensive and not so forgiving with sudden engine stops and so on. A truck turbo is build to withstand very high boost (over 30psi) and can take much damage before it breakes.

The problem with small turbos with very high exhaust pressuare it´s needed to have reducet lob separation so that the exhaust gases don´t get pressed back into the cylinder
On a supercharged engine or a engine with big turbo it´s no problem with high exhaust pressuare so there you can have normal aspirated camshafts to increase horsepower

Normaly would the experts recommend a small turbo to have more power att low revs, but here in sweden we have seen great horsepower with a normal aspirated engine with lower compression and a big turbo.

It´s always a compromise, but i am more into a lot of horsepower rather than early boost, or do as you are thinking, supercharger and turbo.

Look at this swedish Opel (vauxhal) manta with a supercharged/turboed volvo engine

http://www.garaget.org/video/bs01rgolgsd1

The Manta sounds awesome........ ! I need a toothed belt

So is your GT40 sourced from a a truck then? bearing in mind I dont know a huge amount about turbo's, but I was under the impression that diesel turbo's arent good for petrol engines due to the lower EGT's produced by a diesel and have a different turbine blade angle to aid spool up, which render them unsuitable for petrol's.

I am considering a very similar setup to yours with the crossover pipe coming round the front of the engine, however I will be close to the supercharger charge pipe work which may need further fettling to gain clearence, but this not a big deal.

The biggest problem I think I may encounter is the steering shaft on this side (side of the PAS pump). I'm not 100% sure but I think the 4x4 crossmember also take more space. Does your crossover pipe connect to thte turbo manifold from behind the crossmember? as I have diff here. RWD is starting to feel more appealing.

What size pipe did you use for your manifolds and also the crossover?

Rob

Yes its from a truck. No problem with a truck turbo, it´s the racing turbo salesmen who promote special racing turbo, they want to sell of course

On a 4x4 it´s really tricky to draw the exhaust pipes, but i have done it, problem i see is that your car i right wheel steered.

I use 42mm on the cylinder pipes, and 48mm after the collector to the turbo. I measure the pipes on the outside (standard measurements)

Hi Mikael,

I've not made any progress with sourcing a suitable turbo, however I'm also looking at changing my setup to include a charger cooler as it will free up some necessary space (and shorten the distance between the valve and throttle).

I can't see this project happening very soon, but I'm trying to gather the parts on the cheap for a winter project (probably not this year).

I remember you asking for some external video's of my car, well I have some..


https://www.youtube.com/watch?v=b-zxbwmCphM

Rob