Rodger

 

pmsl, oops, you know who i mean

 

indeed.

 

and who is clarke???

 

RCM are out of stock at the moment We have a few catch tanks rattling round, Ill adapt one of those to fit

 

I have a feeling the minimum size of tank for circuit racing is 2 litres?
the object is to prevent oil on the track messing up everybody else's day!
When you're on the edge, oil is a bad thing to find.

 

I think more people reading this thread are worried about ruining their engines on track due to oil starvation, rather than what the MSA have to say about the catch can sizes. (2 litre for upto a 2000cc engine, 3 litre above that, speed events need just a 1 litre tank)

The recirculating system isnt really a catch can in the normal sense, it's more a condensor designed to feed the expelled oil and condensed oil vapour from the breathers back into the engine. The ideal setup for circuit racing a turbo engine would be to vent the recirculating system to a second catch can that is there to comply with MSA requirements, you would only get a very small quantity of condensed oil vapour deposited into that compliant catch can as a result.

 

Just get rid of the PCV valve. You dont need it, it's only there to comply with emisions regs for production cars. (which you are bypassing as soon as you fit vent to atmos breathers anyway). The last thing you want is any oil vapour in the inlet tract, it lowers the efective octane of the fuel and increases the chances of det.

 

so just blank from what i have?

 

If i understand you earlier posts properly, you have the stock piping from the PCV to the turbo inlet pipe removed, and the port on the inlet pipe blanked. You then have the pcv valve piped to the catch tank instead.

If so that seems pretty pointless to me in terms of using a PCV valve at all. All that does is give the posibility that if the catch can fills you will be able to dump a shed load of oil straight into the engines inlet plenum under vacumn, which could hydrolock your engine and bend you conrods if you injested enough oil in one go.

 

John is quite correct, although he's further on around the track than you are JD! I've been trying to indicate that we are on a horses for courses thing here, and not everything suits everybody. The only alternative would be to fit a full return system to anything over 350 bhp and on decent tyres just to be on the safe side. I'm happy if my customers are!

 

confused now alan, should we blank off my pcv valve and have it all vent to atmosphere?

My set-up i was lead to believe when originally installed, was that under no boost the pcv is still returning into the inlet manifold as normal & then vta (via catch tank) on boost.

Best of both worlds in a road/track car?

 

Some breather info here

Breathers

 

Nice clear info there, thanks Andy.
I tend to have an "if it ain't broke don't fix it" attitude, pretty much what your info says.
We appear to now have two camps here, those who are out and out racers, who need an approach which may not be required by more weekendy warriors!
The difficulty is knowing at which point you need to switch from one system to another. I know I'd know when circumstances required it, but how about the chaps out there with thier modified road cars?
Can anybody state a criteria?

 

As a guideline I'd say anything used on the road at over 400bhp or on any car that is going to see 1/4 mile or track use.

My spec C for example lives quite happily on the road without a breather system but 5 laps on track and its filling the intercooler with oil !

 

so thats me completely confussed! i have totally standard breathers and will be doing some track work this year (starts next month at castle) on r888's which are already fitted. I did a 1/4 mile last year and had no probs but clearly i need to now get someting else sorted, but what? its a 94 btw. please!!

 

Under no boost(vacumn) the airflow through the PCV valve is in the direction of the plenum, i.e. air flows into the plenum and then directly into the engines inlet ports. Under boost no airflow goes through the PCV valve, it's efectively a bung.

On the stock setup this is done by teeing into the turbo inlet pipe just before the turbo, the crankcase breather also joins the inlet pipe at this point, so you have the PCV valve and the crankcase breather and the inlet pipe all joined together at that one point. The camcover breathers then T into the inlet pipe just after the flexi join from the Airfilter and MAF sensor housing.

Your descriptions of your system are somewhat confused so to clarify.

Where does the pipe attached to the PCV valve go? Is it to the turbo inlet pipe or is it to the catch can?

 

I would say the safest advice would be that if you intend to do any track driving with any tyres capable of more grip than a stock road tyre like a T1R, T1S etc, (slick or R style tyre like the R888, 048R etc.) you should install a recirculating breather system, irespective of how much power you have.

On standard grip 17" Brigestone SO2 PP road tyres (which were about as grippy as you got from a stock style tyre) i found a breather system wasnt esential at 300BHP power levels, but you still do get some small oil use so need to check the levels regularly during the day. I would sugest the later spec cars with their grippy Bridgestones need a recirc system as soon as you start tracking them even in stock trim.

Fitting a baffled sump will really be based on how much cornering G you can pull, in reality most people dont corner that hard, even when they think they are on the limit they dont hold high G for much of the corner, if the driver is getting the most out of an R888 and the car is a good one in terms of setup, you will hit oil surge issues with a stock sump, the really good drivers/cars will hit surge issues even with a baffled sump and will need a dry sump system.

 

the inlets before the turbo are blanked.

the pcv is in the manifold connected to the block with a tee piece. when there is boost the pcv is closed and the breather is piped to the catch tank, when no boost pcv is open so vents as per stock into the manifold.

as stated above by Alan "if it aint broke, dont fix it" not had any issues to date.

 

Then why did you ask questions about your breather system?

It's a forum, discusions tend to expand on the initial post, and in this case it's been a worthwhile expansion to the thread in a number of areas.

(as an aside, with your setup if you had a good launch and threw oil out of the block breather, as soon as you go to shift a gear you will suck a load of oil into the plenum because you will have a vacumn in the plenum during the gearshift)

 

oh well, will leave as is till a problem arrises.

 

jonfelstead- thanks for your advice! jd- i spose this isnt a good time to ask you wot make and grade of oil you use

 

Silkolene Pro-R 15-50

 

 

no problems

 

Hang on a minute ... all the information is related to oil surge, which is what the sump baffle is supposed to fix and is therefore very relevent. I think the info posted by JohnF is very interesting and useful to any of us who will be pushing our cars power in the future. It's of course completely your choice whether you decide to follow that advice or not.

I find it amazing that so many people on SN offer advice (often with very little relevent knowledge), but when an expert like John comes on here and gives us advice based on his many years of experience you effectively say his advice is not welcome.
No wonder a lot of the experts can't be bothered to post here any more.

 

maybe i worded it wrong.

I was not saying his advise is not welcome, wa just trying to get things back on track.

But be fair on my behalf, I do not know who JohnF is?

 

JF is god

 

that helps

 

It looks like you guys have moved on in discussion, but if you were wondering, here are our test results. Test was conducted on a stock engine, with the twin scroll pan, and stock narrow oil pump. Excuse the lame chart - I don't know how to make a chart on a forum post.

RPM / Factory OIL PRESSURE / BAFFLE PLATE OIL PRESSURE
750 / 22 / 22
2000 / 91 / 92
3000 / 98 / 99
4000 / 104 / 104
5000 / 105 / 104

Crankcase vacuum was not present at anytime during this test even at part throttle and the PCV attached. There was zero vacuum until 5000rpm. The crankcase pressure increased linearly from 0 @ 5000rpm to 20kpa @ 6000rpm. This engine used for this test has stock pistons/rings. Engines with forged pistons will have even greater crankcase pressure readings with a wet sump oiling system. It does not appear that the rubber flaps can be sucked upwards due to vacuum.

Is there a problem with a stock engine and the Cosworth baffle? We do not think so. If there was, the problem would have shown up in our earlier testing. We are absolutely confident that there should be no oiling issues with the Cosworth baffle.

If anybody has any questions, feel free to email me directly at eric.hsu@cosworth.com.

Thanks for your time guys.
Eric Hsu