Inlet and exhaust upgrades???

[944Turbo]

How many other inlet manifolds did promax try during the development of the kit before deciding this option was best on a road car?

I know lindsey have been selling them for a while and may have tried others when they developed it however, I also know they were often criticized for lack of development in the past. I know they are improving in this area, they have an engine dyno now and have made gone to great lengths to promote their head flow testing, I wonder, being cycnical, if the design changed before they started publishing figures.

How long would you expect a level 4 kitted car to last? do they require more frequent service intervals?

What safegaurds are there in a level 4 kit that it wont grenade the engine should it develop a fault somewhere, e.g in the injector harness, a pipe coming off the FPR, etc?

Tony


Tony

 

[AndrewS]

ORIGINAL: 944Turbo
How many other inlet manifolds did promax try during the development of the kit before deciding this option was best on a road car?

I know lindsey have been selling them for a while and may have tried others when they developed it however, I also know they were often criticized for lack of development in the past. I know they are improving in this area, they have an engine dyno now and have made gone to great lengths to promote their head flow testing, I wonder, being cycnical, if the design changed before they started publishing figures.

How long would you expect a level 4 kitted car to last? do they require more frequent service intervals?

What safegaurds are there in a level 4 kit that it wont grenade the engine should it develop a fault somewhere, e.g in the injector harness, a pipe coming off the FPR, etc?

Tony

Hi Tony,

The reason for using the LR intake was becuase it evidently flowed a lot more air than the standard intake (we were happy to accept LR's findings in this respect) and it allowed much easier fitting of the Super 75 Turbo. I don't think the intake is such a contributory factor until revs exceed 5,000 RPM. However, it is able to flow enough air for a 2.5 litre at 8,000 RPM running 1.5 bar boost (hence, it was also selected for future potential). The intake on MarkK's car is the latest deisgn as far as we are aware.

Any car fitted with tuning modifications will have reduced durability compared to a standard car - if used to it's full potential all the time. That's a given when tuning any car beyond what the manufacturer intended. However, if treated with respect and looked after, there is no reason why such a modified car could not rack up the same sort of mileage as a standard 951. However, it is too soon to say with any certainty. Most tuned cars are tuned so they go faster, hence tend to get used harder too. The 951 has well engineered internal components and (from experience) can handle making a lot more power reliably. Brakes, suspension, transmission and drivehshafts all incur more stress when engine power is increased - however, these components (on the later 250bhp cars) seem very capable of handling more engine power also.

Major service intervals are essentially the same, but we recommend using Royal Purple fully synthetic oil (or any other ester based synthetic equivalent). Oil changes are also recommended every 3,000 miles (along with a visual inspection). Any tuned car needs to be maintained in accordance with how it is used.

Level 4 kits are specified with a wide band O2 sensor fitted as stadard to the custom exhaust (this is used when we map the car). A suitable WBOS Gauge is recommended, but is optional (the purchaser is free to choose their own). Knock control is deployed using the standard Motronic DME ECU.

Hope that answers your questions.

Regards,
Andrew

 

[944Turbo]

Fair enough on the servicing.
I believe intake manifold design is about much more than just maximum airflow, but then I believe development of performance kits should be more than just buying in off the shelf stuff from another company (though obviously promax did the mapping) - maybe thats just me []
Tony

 

[AndrewS]

Meeoow!

What would be the point in developing a new turbocharger, injectors and head? (for example) when perfectly good ones are available already (at a cost we could not match if we developed our own). Even major manufactuers buy in components from others - it's called economies of scale and is necessary to sustain a business and enable that same business to support their customers long term by remaining profitable.

It's matching the comonents together than generates the results. Our custom exhaust solution and mapping are most responsible for yielding the power on Level 4. These items were developed in house.

Roll on the next dyno day! ;-)

Regards,
Andrew

 

[944Turbo]

'perfectly good' doesn't mean that they cannot be improved upon, the cars left the factory with perfectl;y good heads and turbos. The wheel was perfectly good until someone fitted a tyre to it, the crossply was good rill the radial turned up.

An inlet manifold with longer equal length runners and matched to a head may be substantially better than the lindsey item, I know there are amateurs who are trying this, if they are succesfull no doubt promax will jump on them. Letting others do development is cheaper but does not put you at the forefront of the technology, maybe I expect too much as the premium paid is relatively small, maybe because I am blessed with an amount of engineering understanding I can assemble my own parts that work direct from suppliers so I don't need you, I guess there are others who do not know a spark plug from a wastegate and who are happy to pay for your service.

If you were to develop something new that worked well at a good price I would probably buy it.

Tony

PS how many extra BHP per psi do you expect my engine to generate going from 18 to 21psi just so we can see who is closest

Tony

 

[Hilux]

many dynos have no atmospheric control systems meaning that their figures from the same car can vary quite dramatically between 2 days with different ambient temperature, barometric pressure and humidity.

Well put Fen

My car was 250 bhp in 2005 and 253bhp in 2006 (max boost was 0.8 [&:]) and I note that it was cooler and damp weather in 2006 (something turbos particularly like) []

Question? Does WRC measure temp and humidity level changes and recalibrate automatically?

 

[Diver944]

ORIGINAL: Hilux

Question? Does WRC measure temp and humidity level changes and recalibrate automatically?

Yes, that's the main reason I've booked them two years running. Their system compensates for differing conditions and people like Rick have been there many times on differing days and got results within a few percent.

I think there would be very few chassis dynos in the country that would have given your car almost identical results from one year to the next []

 

[Fen]

When they aren't running in "shootout" mode they close the door to seal the cell and the fans change 100% of the air in there in I think 3.5 seconds or something similar to minimise the effect of atmospheric conditions.

 

[333pg333]

So apart from the Lindsey ones, has anyone done anything with their heads, intakes, exhausts etc that works well for our r.h.d. cars or have we all made gains in power mostly with increased induction through chips that allow us to run higher boost on our larger turbos?

 

[944Turbo]

I have the orignal development essential styling exhaust on my car - It was developed by Janspeed and did offer an increase in performance. It was a longway back and my car was down on power through boost leaks etc. but they dynoed it before during and after. Interestingly IIRC it made more power with a performance front box where the cat used to be not what I would expect.
Head and inlet are pretty standard on mine, just a minor reprofiling of the ports.
IIRC Rick has had some work done to improve his standard manifold
The Swedes are doing some interesting inlet manifold work with longer equal length runners.
Tony

 

[944Turbo]

PS
Thats inlet ports on my head obviously the ceramic liners limit what you can do on the exhaust side.
Tony

 

[AndrewS]

Hi Tony,

With respect to increasing boost from 18psi to 21psi - I hope it does not go the same way as another member's car did in May 2006. You will probably increase torque a little somewhere but I think you will lose power. 21 psi is nearly 1.45 bar. 18psi is a realistic maximum unless specific changes are made to address the issues that will prevent increased boost resulting in inreased power.

With respect to products, I can't really say anything else. We don't make statements about what we are going to do (only what we have done).

It is possible that with enough research and funding we might be able to make a better wastegate; a better induction kit and a better exhaust (for example). However, it may not be a viable proposition becuase of the small number of potential customers ( UK - exchange rate rules out the USA). In the USA the customer base is large enough to support the development of some products for the 951 - also the exchange rate favours exports. The German tuners don't bother with the 951 and neither do many others (historic racing has raised interest a little in Europe) - why? The value of the 951 is such that very few can justify spending big money tuning their cars. Hence, only relatively low cost products are generally considered. Compare that to a 996 Turbo owner who may think nothing of spending an equivalent of 20% of the cars value on upgrades and performance parts. That sum could buy two reasonable 944 Turbo's! This also accounts for some of the poorly researched and developed products that we have seen from the USA (this is not a generalisation - but some are a very poor fit and finish).

Personally, I like the 951. It's a hugely under appreciated car and has amazing performance for the money. Many others evidently feel the same too. However, not everybody likes to tinker. Possibly 90% of current 951 owners would probably rather entrust the work to someone else than take the risk themselves - I wish that kind of service was around when I had my first 951.

Regards,
Andrew

 

[944Turbo]

I agree 21psi is a risky area and wouldn't want to run there all the time, but with the right timing and mixture it can be relatively safe, especially if the turbo is well within its efficiency range. I do view the standard bores as being akin to a saturn 5 rocket engine at high temps and pressures - i.e. flexy.
Interstingly before my head gasket went last year my boost controller was iffy (leaking) and I occasionally hit 30+psi it certainly felt a lot more juicy at those pressures, wheelspin in 4th - how much power / torque for that?
Tony

 

[333pg333]

There are guys running in excess of 20psi daily. Mostly in the U.S. and some of those crazy nordic dudes. Some of them don't have their cars on the road for that long though as they haven't taken the precautions for their engines. Depends on octane of fuel too obviously. However if you do the work it can be attained I'm sure. It does cost though and as Andrew says not that many people are interested in spending big bikkies on our cars. That's one thing I do envy of our American friends. How cheap auto parts, work, and cars are there. I saw on Rennlist where a 944t sold on ebay for $26k U.S. which is a good sign for all of us. It was a very clean car but it did have a few Lindsey mods so it wasn't sold as original which is another good thing for us.

 

[sawood12]

I'm not convinced that investing alot of time and effort on inlet and exhaust manifolds is necessarily worth it. Maybe on very very highly turned cars where the manifolds are the weakest link in the chain. Also it's something you have to be sure you know exactly what you're after before you start as the manifolds are fixed designs they are only ever going to be optimised for one set of conditions, i.e. a specific RPM, temp, pressure etc. and as soon as you are outside of those conditions it is no longer an optimised design and in fact might even be hurting you. That is why some cars feature variable geometry inlet manifolds that change their volume and shape to a more optimised shape through the whole rev range and all driving conditions.

For example, if you compare the 993's with Varioram the on-paper power and torque figures are exactly the same as the non-varioram models as are all the performance figures. However people reckon the Varioram cars 'drive' better. So it doesn't seem worthwhile to chase extra performance from optimised manifold design - I doubt you will be able to get significant gains over the standard manifold, certainly when you consider the amount of time and effort, not to mention cost, it would take to develop. In fact i'm not sure if Porsche carried over Varioram to the later 911 models so they seem to have come to the conclusion it's not worth the effort - you are much better playing around with cam timing and valve lift hence Variorcam and Variocam Plus. Could such a system be designed for retrofit to a 944 turbo, maybe from a modified 968 cylinder head? I'm sure the scale of such a project would even put off Rick Cannell!

 

[Fen]

That's an interesting concept, Scott. My EMS has a function to activate VTEC, which could be used with a solenoid to operate the 968 variable cam timing with a suitable head. Biggest problem would be using a solenoid to control the level of oil pressure needed to make the actuator move.

 

[333pg333]

So Scott are you saying that if you achieved greater flow numbers it could still actually hurt you? You can attain greater flow numbers if done correctly at a price and I agree that ultimately if you were able to optimise the variocam system it would be ideal. This has been done but it is expensive as you know.

 

[DivineE]

I shall be carefull when giving information which is 2nd hand but I have been informed by a reliable source. Who's knowledge of 944's is borderline scary that the shape of the original inlet manifold which tappers inward as it goes further back is not an accident! Apparently this allows the same pressure to be delivered to all four cyclinders which is crutial on turbocharged cars and this is where the Lindsey intake manifold goes wrong.

Now I'm no expert and don't have anything to sell but it makes sense to me that if you have a tube of equal width fed from one end the cyclinder nearest the feed is going to get more pressure than the one furethest away (just considering what would happen if you pumped water under pressure into it??! Seems to make sense that the shape is important as well as the maximum capacity for flow?!

On that basis I'd say the best idea would be to save yourself some money and try just improving the casting on the original manifold, let Porsche pick up the tab for getting the design right.

Regards,

Ben

 

[Fen]

Fluid dynamics is incredibly complex, but basically I think if there is sufficient volume coming into the manifold (i.e. through the throttle body) then the length of the individual runners would not affect the pressure at the outlet of each. That assumes a constant and equal rate of leakage from each runner, however. In practice the inlet valve opening and closing means pulse-tuning has a part to play also.

Regardless however I think it is a safe bet that with the size of the smallest orifice in the inlet path (after the turbo) that there is not enough flow to create the balance I described above, hence it would be correct to assume #4 would not get the same flow as #1 with a purely equal length manifold. The plenum is (as I understand it) intended to compensate both for the pulsing and any inability for the inlet to supply sufficient air at any given moment by effectively providing a reservoir to act as a damper.

The Porsche manifold has quite a small plenum fed from the front with unequal length runners as we all know. The Lindsey manifold has what appears to be a similar size plenum with equal length runners fed from the centre. That central feed should even out some of the problems with differential between cylinders (though #2 and #3 probably get better flow than #1 and #4). Where it might fall down (or not; I don't know what it's design aim was) is that the length of the runners will favour a particular engine speed. If I were cynical I might say that the runners are the length they happen to be simply as that's what would fit. In fact as they mention the length of the runners not once in their sales blurb maybe it isn't just being cynical... Whatever the reason they are short and as I recall long intake runners produce most torque, hence short ones must produce least. That would seem to be borne out with Mark K's car.

Compare the Jon Milledge intake. It seems to have a much larger and tapered plenum fed from the front, but again with short runners broadly the same length as the Lindsey ones. The major difference is that the JME one runs individual throttle bodies hence the inlet to the plenum is unrestricted and flow is better managed to the individual cylinders which improves power and torque in itself. Pulse tuning still comes into play, but I am not entirely sure what difference the lengths make in comparison to a single-throttle set up. It could be a case of what will fit with that design also of course, because fitting is quite important for a successful manifold.

 

[DivineE]

Cheers Fen you are a hugely usefull resorce on technical matters and I do love learning bits from listening to you Rick and Jon talk. I'd love to hear Rick and Jon's inputs to inlet design also?? - If your reading guys.

Ben