My draw through turbo

[advinnie]

Yes I have a boost sensitive fuel pressure regulator fitted in this draw through set up.

[madmike]

Hey Adam, Yep had to 'Learn' to drive a DOCE you could try a 140 & a 152 main

[advinnie]

Well I found out why I’ve been getting all confused with jetting, I took all my jets to a local shop and told them what my issues was with changing the jets and the A/F ratio responding in the opposite way to witch it should. Any way my 160 mains have seen missed stamp and are actually 145’s, my 152 main have been drilled to 172
So started over from scratch with all new jets.
Now this is what I’m running
Idle-.50’s
Mains-140’s
Air-180
Emulsion-F11
Needle-250
Pumps- .50 & .70
Now at idle I have a 16.1:1 A/F
Cruising is at 13.4:
WOT at 10 psi is now 11.4:1
While on a cruise I have 13.4:1 then I floor it the A/F ratio drops to 10.6:1 for a few seconds and then rises to 11.4:1 and stays there till I come if the power.
The throttle response is so crisp and shape now and there is no more hesitation/ stumbling around 2800rpm when gently accelerating witch I had to power through before but now thats all gone

[rubenski]

Great!

[advinnie]

Cheers mate.
Now I’ve finally got around to installing the Oil temperature gauge although the gauge is not yet mounted in the correct position, I was not trusting my “save my bug” oil temperature warning thing that replaces the dip stick cause it was hardly moving but I now know it it’s correct. I have the engine running for 20 minuets then I done a two mile drive back from work and it was a hard/ fast two mile drive as well and the oil temperature never went over 68 degrees C and with in a minute of stopping the oil temp had all ready dropped two degrees. It’s only 8 degrees C out side today so that may not be helping or it could be that the second Oil cooler is to large? And the fan is not running before anyone asked.
Here’s a photo of the oil temp and one of how I’ve installed the oil temp sender. The silver block screws into the case where the stock oil pressure sensor is meant to go and the black union is the turbo oil feed.

[buguy]

That's awesome news. Now you know your not crazy!

[Clonebug]

You should always check every jet for accurate size. If they were used they could easily have been drilled and if new they can easily be wrong.
I had that same problem with my Pict 34 jets.
I ended up getting a cheap set of micro drills and used them to size and drill jets.
I didn't have a tapered reamer but it sure helped to have the drills to check sizes.
Otherwise you are just, as they say......pissing in the wind.

Once it starts pulling hard in third and fourth gear.....you will know you are putting out some decent power when your transmission starts shifting hard or sticking when trying to shift.
You then have reached the next step and spun the syncro hubs hubs in third and fourth. You will then have to pull the trans and get the hubs welded to handle the extra torque.
It's not a big deal but it will be frustrating since you just got it running good.

I did it to my 67 trans first......replaced it with my 68 spare trans and then slipped that one before I got the 67 trans gone thru and fixed.

It cost me $350.00 to have TimsACVW go thru the 67 trans, weld the hubs, replace reverse gear and a new main bearing. Everything else was in great shape.
It shifts like butter now.

[advinnie]

How much boost/power was you putting through them boxes?
All the old jets I had came from eBay.
On a slightly different note I’m looking at fitting an intake air temperature sensor (after the turbo) but was wondering what temperatures are Safe and what’s the limit.

[Clonebug]

My trans went once I figured out how to keep from going lean at 13 lbs. boost. That was when I added the float bowl vent extension to the carb.
Once I was able to make a full pull all the way through third and fourth gear the weakest points started showing up.

Be careful which IAT sensor you get.....you want an "open element" style sensor for fast response.
As for what temps are safe.....it will depend on what you have for timing control.
I have seen boosted temps range from ambient when using a quality intercooler or WI to as high as 265* F at high boost and no intake cooling.

That is where timing control and boost retard comes in.
The warmer the air the less dense it is......therefore the less fuel it will suspend and less power it will make for a given afr reading.

I have not seen a carbed turbo system ever have an IAT sensor installed and log intake temps to see how much cooling effect the fuel gives.

On an injected engine you add fuel right at the valve so you can't really see how much cooling you get if any due to the short time period before igniting it.
I can see the cooling effect with my Water Injection since I know what temp the air will be without it using the RB Racing Calculator.
I get 100 degrees cooling or more with my WI and 30 plus degrees with the intercooler which on a cool day puts me back to ambient temps at 20.5 lbs boost.
That can be a gain 15-30 hp if you do the math.

[advinnie]

Well I’m all ready pulling hard in 2nd gear at 6psi @ 3700 changing up at 4500rpm, then into 3rd with a 5psi boost @ 3200rpm hitting 10psi by 3800rpm, then 4th gear with 7psi and hitting 10 psi around 3500rpm
I’ve had a go at turning off the rpm limiter (set at 4800rpm) but that’s dangerous for me cause the boost kicks in fast when I floor it in 1st gear and I have trouble changing quick enough and end up hitting 6000rpm the same in second.
So is it even worth fitting a temperature sensor in the intake on this bug?

[Clonebug]

You will need to hit around 13-15 lbs boost to get enough torque to overcome the syncro hubs.
The difference between 10 lbs and 13 lbs is a noticeable difference and you have to do it multiple time through the upper gears to get the load on the turbo.
It might not happen right away and you might also not have enough tire to hold it....but once that happens you can laugh and cry at the same time because you are moving up in the turbo world......

That's why I pull my buggy apart every winter.......1....to check everything.....2.......to upgrade the parts that won't hold the power......
This winter it is the Stage I clutch that won't hold.

[advinnie]

I've had an idea (witch is not good ) I'm thinking of making my own T3/T4 turbo but I just don't know enough about turbo to figure out the out come.
What I thinking is that if I use the turbine I have know from my T3 and housing witch is a .36 A/R and use the larger T4 compressor I should get more air flow/boost for the same axle rpm rpm when compared to my current turbo?
But will using a larger compressor cause turbo lag to increase?

[Clonebug]

Yes it will......a larger wheel is bigger and heavier. Therefore it takes more to get it spinning hence the lag.

If you have a T3 turbo it is already on the large side for a 1600 unless you are revving to 7000 rpm and looking for big hp numbers.

I looked a little bit and those turbos will support from 150-325 or more hp depending on the trim and compressor size.
With a 48 turbine housing you are looking at up to 300 hp but without spinning to 7000 rpm you will need 30 plus lbs of boost to support it with 97 CI.

Rpm is where you gain the hp after a certain boost pressure. If you hold it to 4800 rpm you will be lucky to see 130 crank hp at 10 lbs boost.

In order to make 225 crank hp you will need 28.37 lbs. boost to be at my level if you rev to 4800. I have 5 more CI. than you do.

You aren't working that turbo hard enough without getting a bit more rpm.

[advinnie]

Ok I will drop that idea then

[petew]

Cheers mate.
Now I’ve finally got around to installing the Oil temperature gauge although the gauge is not yet mounted in the correct position, I was not trusting my “save my bug” oil temperature warning thing that replaces the dip stick cause it was hardly moving but I now know it it’s correct. I have the engine running for 20 minuets then I done a two mile drive back from work and it was a hard/ fast two mile drive as well and the oil temperature never went over 68 degrees C and with in a minute of stopping the oil temp had all ready dropped two degrees. It’s only 8 degrees C out side today so that may not be helping or it could be that the second Oil cooler is to large? And the fan is not running before anyone asked.
Here’s a photo of the oil temp and one of how I’ve installed the oil temp sender. The silver block screws into the case where the stock oil pressure sensor is meant to go and the black union is the turbo oil feed.

I've got my oil temp sensor in my deep sump. Not the best place for it, but something to show me how things are going. To be honest, it takes a pretty hot day for it to go much over about 50degC. Even on a super hot day, it's never above 90degC. I've got a secondary oil cooler, but no fan and it stays nice and cool. I would ask though, have you got a thermostat on your secondary oil cooler? Coz in cold climates you really need it. I have one. Otherwise, the motor takes ages to warm up, which is not good for it. And on a super cold day, you'll pop an oil line off, like my brother used to in his split bus.