Saturday 10 April 2010

Flowbench testing

Just a bit of a write up this week on some parts brought in by Andrew Grogan for testing.
Andrew looked high and a low for a really good Evo 1 to do a restoration project on, but sadly settled for a Winner red.

He then proceeded to pull it to bits and is reconditioning everything which could be and replacing everything which couldn't, we are talking about a full-on nut and bolt restoration here, every step and every part has been methodically logged, pictured and written about and lot of people eagerly await the results of his years of hard work.

All results below were taken at 10" of depression.

First up on the flowbench was a mildly reprofiled throttle body, it looked really nice and I would have put money on it giving 2 or 3cfm extra, result? Zero improvement over standard.

Well it could only get better and next up was a bit more interesting: An OE intercooler with the end tanks removed and a new more modern core welded inbetween them. The exit/entry pipes had been mildly re-profiled and polished, the quality of welding was superb and we counted less tubes than the OE 'cooler meaning it had larger section ones fitted. Looking into the core you could see it was a more aerodynamically friendly affair, but still tube and fin construction (see earlier intercooler article).




On the bench the OE intercooler flowed 153cfm.
The re-cored one flowed 165cfm.

So not a bad result for a simple core change and a bit of cleaning up, I think they could have got more by changing to a bar & plate type, or at least, it would have been interesting to test one anyhow. As outlined before if you want more power then get more airflow by trading up to larger section core, but if you want to keep your integrale looking standard whilst gaining a bit and lightly modernising it then it's not a bad mod.


Andrew then brought in a head he had done by someone without a flowbench so had no figures for it. It had been very tidily done, no major changes to the port geometry or valve and seat angles, just some rounding off of the short-side-radius and knife edging on the port splitter.



A stock head flows 137cfm
And his was up to 155cfm




So again a good modest improvement, high CFM figures aren't everything and I didn't have the time to do any valve-in tests.

We tested an OE cast iron log manifold on an umodified head V Andrews tubular item:






As you can see, nothing really unexpected, but interesting to see nonetheless. Looking closer at the figures, at least the tubulars best and worst flowing headers are within 10cfm of each other whilst the OE log has a much larger 18cfm difference.

This was supposed to be just a factual post on what we found out from the items tested, but lets wander off for a moment and look a bit closer at the usual manifold debate questions.

Are you going to see a non flow loss ex'manifold on an integrale which keeps the turbo in its original position? Well I think you're going to struggle! I'm saying this not only from what we have found here, but also because we have a life size model along with modelling kit in the workshop which we are making our own on so I know how difficult (impossible?) it is to create the perfect manifold.

Do you really need equal length tubes? Yes. Look at the tubular one on test, the shortest pipe has the worst CFM figure, it has this because of the number of bends and restrictions in it, so what if we build a manifold purely based on equal flow rates for all four pipes?
What is the point in an equal length manifold if the flow figures are all over the place?
Food for thought and open to discussion, but the answer for me would be equal length and equal flow.

Another widely debated topic is whether the integrale 16v inlet manifold is better than that of the Fiat Coupe, many people claim it is so we did a back to back test and found no difference between the two at all. Both showed a 36cfm loss when bolted to a head flowing 168cfm on cylinder No.1.

Sunday 4 April 2010

Flowbench and cylinderheads

Some people don't realise we have a flowbench at Deltaparts.

Many people have no idea what one is so let me explain.



Ok, as previously discussed in an earlier post airflow is probably the most important thing to consider when trying to increase the power of your engine, if you can get more in and match it with more fuel you are going to get more power, simple.

How do you know if your modifications to the airways have done any good without checking the output of the engine? You don't unless you have a flowbench to give you a good idea of what is going on. You see, sometimes you can make things worse or spend a lot of time on something which gives little or no improvement.

Don't buy a reworked head from someone who cannot prove what they have done.

(Very!) basically a flowbench has a few electric fans inside it which draw a vacuum through the test hole, they can be reversed to blow and can also be controlled to give a certain airflow at which you take your readings at, the basic Superflow 110/120 is what many people have, it is rated at testing up to 100bhp per cylinder and maxes out at 185cfm (cubic feet per minute)

Ours is a bit bigger, it runs 6 motors and will pull your arm in if you get too close! It pulls over 28" and 250cfm quite easily. 28" is called test depression, it is read from a manometer which is T'd off from one of the chambers within the bench. The more vac and CFM you can pull the closer and more accurate to a real life situation you will get. Air is much heavier than you would think and (just like a car going round a bend) the faster it goes, the less chance it has of actually getting round smoothly so the more air your bench flows, the more accurate and closer to real life your results will be.

Whilst it has to be said that your own flowbench is better used with your own before & after figures it's sometimes good to compare with others, so the ability to be able to check at 10 or 28" is useful as not everyone uses the same test depression.

The Superflow has liquid filled manometers to take the readings which you manually log, we have digital ones on ours which are displayed on the laptop screen and can be logged into the laptop if needed. This makes the job much easier and quicker and photographing your good work a bit easier too as you will see.

With a fair bit of work we can get an integrale 16v bare inlet port up to 170cfm, it isn't just the high cfm numbers which you are chasing, you need good air speed throughout the port, no good if the air speed is too slow or too high even. We read airspeed in FPS (feet per second) with a probe which we can push into any part of the port to check for high, low or dead areas where nothing much is happening and shape the port to suit.
There isn't much point in beyond 170cfm BPF either if you are still using the OE sized valve or untouched inlet manifold as it will pull those figures back down once it is fitted.


Below is a graph of results from a head I did last week compared to standard. It shows the flow of the port with the valves fitted and at different lifts in increments of 1mm. Stock head versus modified which has a 3 angle valve seat too. It also shows a comparison at BPF (bare port flow) no valves fitted.



As you can see, it flows more air from the start, but really comes into its own at the higher lifts from about 7mm onwards.
What is interesting to note is that with the standard ports the CFM with the valve in at full lift matches the BPF. With the modified port and valve in test it never matches the BPF (well it might do if you lifted it higher), this indicates that we could fit slightly larger valves and maybe make some small gains.

Why do you need a gasflowed or ported head on your engine?

Many people modify their cars without doing much to the head, I don't know why this is, maybe because they don't understand how important it is or because it's not a bolt on shiny part which you can admire and show people....

About 75% of the power in your engine is made in the cylinder head so it makes sense to start here. Many modifications which you do to an engine have a downside to them, the cylinder head is not one of them. When you fit a properly modified head you gain in power, driveability and economy - it's a win-win situation.
As outlined in the engine related articles it is important to start an engine modification project by getting the basic core of the engine right before going any further. Any clod can bolt on a huge turbo and ram the air in to get a bigger power figure, not of much use if the car is horrible to drive though.......


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Friday 2 April 2010

Valve train upgrades

Small, but important and impossible to find off-the-shelf ones of the correct dimensions. That is the conclusion I came to after reconditioning a few cylinder heads - we just couldn't find any which were of the correct OD and ID so had a batch made for ours and your use which fit easily and don't give that 'But the valve still flops around like the guide is 100,000 miles old' feeling like most do.




Made from Aluminium-bronze these fit just great and will outlast the originals easily. If you want them fitting then send your head up to us and we'll do them for you, we have the correct tools and equipment to do the job properly and with the miniumum of fuss.

If you've managed to make a mess of removing the old ones and require an oversized OD then contact us, we can order in some for you.

Also available are Nimonic exhaust valves, nice, light and swirl polished on the back of the heads on the standard size and they can be made in bigger diameters if you need a big valve head for quicker turbo spool up time. The last set went out to a customer as quickly as they came in so we only had time to get these shots!

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To finish things off with the ultimate in valve reaction time and lightness are these new tappet buckets with tiny shims which go underneath and sit on top of the valve stem. Buckets are anti-friction coated and the weight saving is well worth having.




Prices will be uploaded on the website.

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About Me

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Welcome to the Deltaparts Blog, here you will find, well, anything which is on my mind I guess, but mainly things to do with the Lancia Delta integrale and in particular anything to do with my business, Deltaparts. It will be a bit irregular as it's not every day (or even week) that something worth mentioning happens. I would like to try and make it interesting - at least to some people anyhow, but also hopefully accessible and readable for the average 'man on the street' so I won't bore you with loads of large words, bombastic overblown sentences or technical jargon. I will describe on here how lots of the parts that we sell came about as there isn't room on the website ( www.deltaparts.co.uk ) to explain. I hope you enjoy reading it as I do writing it, when something becomes a chore you know it's time to stop doing it....