Individual throttle bodies?
- Thread starter Andy97
- Start date
I have been looking at doing this to my S2. I am slowly collecting info and looking at parts. But when I do it I'm going to go for stand alone management wasted spark etc etc. But it wont be this year as I have too many other things to do to the car.So I'll be starting on it next winter.
This looks interesting...
http://forums.pelicanparts.com/pors.../180639-project-itbs-part-1-parts-arrive.html
http://forums.pelicanparts.com/pors.../180639-project-itbs-part-1-parts-arrive.html
edh
New member
these people might make you an inlet manifold http://www.boggbros.co.uk/index.html
Not sure if this helps but a few years back I built a mk1 golf gti and fitted a 2.016v engine (popular conversion about 10 years ago) I ran in on the standard Bosch fuel injection for about a year and did a few track days. Eventually I decided to fit throttle bodies with appropriate emerald Ecu the kit cost around £1500 plus bits and pieces and rolling road time for set up so cost in the end close to 2k
For pounds per BHP it was defiantly not worth it and the gains were not what I expected, the power curve was moved further up the rev range substituting bottom end torque for top end power I did have peaky cams fitted admittedly but low down power was really poor but kept between 5k rpm and 7k rpm it was rapid, i would not recomend this for road use only track use due to revy nature.
My bhp before fitting was 168bhp @ 6200 and peak torque was 151@ 4300 After fitting throttle bodies peak power was 191@6900 and peak torque was 176@ 5800 so in a nut shell apart from awesome noise I would not waste my money but this is only my opinion from my experience
For pounds per BHP it was defiantly not worth it and the gains were not what I expected, the power curve was moved further up the rev range substituting bottom end torque for top end power I did have peaky cams fitted admittedly but low down power was really poor but kept between 5k rpm and 7k rpm it was rapid, i would not recomend this for road use only track use due to revy nature.
My bhp before fitting was 168bhp @ 6200 and peak torque was 151@ 4300 After fitting throttle bodies peak power was 191@6900 and peak torque was 176@ 5800 so in a nut shell apart from awesome noise I would not waste my money but this is only my opinion from my experience
Yea admittedly the car was mapped for the cams which were in there maybe if less peaky cams were used then power would be delivered differently, the other problem is that the 8v engine is not a very revy engine and is renowned for low down torque, the 2.516v engine 944s would surly benefit more.
ORIGINAL: edh
Sounds Sounds expensive andy. Well worth checking out tom's augtronic stuff I'd have thought. He has shown useful gains on an 8v.
Most itb setups will cost more than your car is worth []
I have no doubt that you are right in every respect Ed, but what's common sense got to do with race cars! I am already in touch with Tom so we'll see. The 24S is good fun and handles well but could do with more power, a gain of 20-30 bhp would be worth it.
As a comparison, there's an mx5 raced in the same series as me which has ITB but is stock otherwise. It has 150bhp as opposed to 115 and it flies!
I suppose the first thing to do is actually find out what power the car has now and whether its a standard 150 Bhp engine or a standard 163 Bhp engine. Not that all the original horses will be present anymore anyway. Reading a recent article in 911 & Porsche World magazine, Tom Barker at Augment Automotive makes the point that he has never seen a 944 deliver what its supposed to. Still, if the engine is an original 150 Bhp engine, the first, and probably cheapest, upgrade is to nip down to PH Sportscars and see if he has a 944 engine in. He told me a short while ago that I could have one for £350 plus fitting. Then it will be time to visit Tom.
Indi9xx
New member
Getting big power out of a 944 non turbo engine, no matter which one, 8v, 16v, 2.5, 2.7 or 3.0 involves putting the engine internals on a serious diet and and increasing the available RPM, after that, throttle bodies begin to give rewards.
The crankshaft, rods, pistons, flywheel and clutch cover are all bloated on the 944 non turbo engines. The flywheel and clutch cover and crank are heavy weights because they are required to smooth the engine out due to very heavy pistons and rods, combined with a long stroke.. So the use of lighter weight, forged, short skirt pistons, very light weight rods and a modified ported block will remove a massive amount of parasitic losses, increasing torque and BHP while also making the engine much more responsive.
Increasing the rpm limits, with the right attention to breathing, bring about exponential gains in top end power. But with the 944 oiling system, increasing it beyond 7000 rpm involves the oil cavitating and foaming inside and after the oil pump. So I would recommend a dry sump engine if you wanted to improve performance with a higher rev limit.
The camshafts in a 944 non turbo, like the turbo, are completely pitiful, even breathing at sub 6000 rpm levels are very poor, due to a "designed in" limiting factor of the cam, deal with this, and you will make bigger power levels.
Once all this is done, throttle bodies on a 944 non turbo will make power... Before it, they will just be along for the ride.
The problem is, this kind of level of non turbo modification has never made sense to consumers, so very little has been done by the pro's to release this power, as the cost of these modifications would not only make up for the difference between the very tunable 944 turbo, but would probably buy you a couple of complete good condition 944 Turbos.. So I do not believe, that anyone would be able to give you accurate dyno charts of what these modifications would reap... But what I do know, is if someone had the money, or the skills to do it themselves, it would make some decent gains without a doubt.
One issue with the throttle body idea, is that at part open throttle positions, you end up with a very short pulse length tuning intake length, as the not completely open throttle butterflys, or slides, would cause pulse reflections which would no longer occur at the right point for making gains of pulse length harmonic scavenging for the engines intake, which is poor on a 944 anyway, partly because the cam is just not up to the job.. the result of this is that the engine would feel less responsive even with a good intake, retaining a plenham and long runners to maintain pulse length harmonics as well as ram loading the port.. The worst scenario would actually be putting throttle bodies onto a 944 non turbo with short stub adapters and just ram trumpets on the bodies, which although might be good for power around 9000 rpm, it would be aweful for power elsewhere.
There are better things to do to a 944 non turbo for extra power unless you have very deep pockets.. One idea would be to just fit an S2 engine, another option would be to install a 968 engine, which in a Lux make for decent power and a street sleeper look.. However S2 and 968 engines do not grow on trees.
The crankshaft, rods, pistons, flywheel and clutch cover are all bloated on the 944 non turbo engines. The flywheel and clutch cover and crank are heavy weights because they are required to smooth the engine out due to very heavy pistons and rods, combined with a long stroke.. So the use of lighter weight, forged, short skirt pistons, very light weight rods and a modified ported block will remove a massive amount of parasitic losses, increasing torque and BHP while also making the engine much more responsive.
Increasing the rpm limits, with the right attention to breathing, bring about exponential gains in top end power. But with the 944 oiling system, increasing it beyond 7000 rpm involves the oil cavitating and foaming inside and after the oil pump. So I would recommend a dry sump engine if you wanted to improve performance with a higher rev limit.
The camshafts in a 944 non turbo, like the turbo, are completely pitiful, even breathing at sub 6000 rpm levels are very poor, due to a "designed in" limiting factor of the cam, deal with this, and you will make bigger power levels.
Once all this is done, throttle bodies on a 944 non turbo will make power... Before it, they will just be along for the ride.
The problem is, this kind of level of non turbo modification has never made sense to consumers, so very little has been done by the pro's to release this power, as the cost of these modifications would not only make up for the difference between the very tunable 944 turbo, but would probably buy you a couple of complete good condition 944 Turbos.. So I do not believe, that anyone would be able to give you accurate dyno charts of what these modifications would reap... But what I do know, is if someone had the money, or the skills to do it themselves, it would make some decent gains without a doubt.
One issue with the throttle body idea, is that at part open throttle positions, you end up with a very short pulse length tuning intake length, as the not completely open throttle butterflys, or slides, would cause pulse reflections which would no longer occur at the right point for making gains of pulse length harmonic scavenging for the engines intake, which is poor on a 944 anyway, partly because the cam is just not up to the job.. the result of this is that the engine would feel less responsive even with a good intake, retaining a plenham and long runners to maintain pulse length harmonics as well as ram loading the port.. The worst scenario would actually be putting throttle bodies onto a 944 non turbo with short stub adapters and just ram trumpets on the bodies, which although might be good for power around 9000 rpm, it would be aweful for power elsewhere.
There are better things to do to a 944 non turbo for extra power unless you have very deep pockets.. One idea would be to just fit an S2 engine, another option would be to install a 968 engine, which in a Lux make for decent power and a street sleeper look.. However S2 and 968 engines do not grow on trees.
Jon, that is a fantastic and very useful reply. Many thanks. I certainly don't have vast wads of cash - some but not vast wads! The aim is to get a bit more power for the race car but I have no illusions about it suddenly becoming a Honda VTEC beating motor!
I can't do the engine swaps mooted, as they are not allowed under the series regs - I can modify the engine but it has to remain the same type as fitted. The car runs in a 1800-2500cc class, too, so increasing capacity is not on, or else I shift classes and come up against S2s and 968s.
At the end of the day this is very much a budget race car, raced in a budget series and really is not worth me going down a very expensive engine rebuild route with bespoke pistons and new internal componentry etc. That sort of work really does sound like professional or even works level stuff. And as you say, it just does not make sense. Pity Porsche didn't do it themselves back in the day but such is life.
I am interested in the sorts of mods and gains that Tom Barker seems to be able to achieve, and at my budget that does make sense. A 20-30 Bhp gain will make a big difference to me, if it can be achieved, whilst maintaining reliability/ robustness - at least it should put the car on a par with the MX5 Mk3s (in terms of power to weight) that I have to battle with in my class. The only problem then will be me!
I can't do the engine swaps mooted, as they are not allowed under the series regs - I can modify the engine but it has to remain the same type as fitted. The car runs in a 1800-2500cc class, too, so increasing capacity is not on, or else I shift classes and come up against S2s and 968s.
At the end of the day this is very much a budget race car, raced in a budget series and really is not worth me going down a very expensive engine rebuild route with bespoke pistons and new internal componentry etc. That sort of work really does sound like professional or even works level stuff. And as you say, it just does not make sense. Pity Porsche didn't do it themselves back in the day but such is life.
I am interested in the sorts of mods and gains that Tom Barker seems to be able to achieve, and at my budget that does make sense. A 20-30 Bhp gain will make a big difference to me, if it can be achieved, whilst maintaining reliability/ robustness - at least it should put the car on a par with the MX5 Mk3s (in terms of power to weight) that I have to battle with in my class. The only problem then will be me!
Indi9xx
New member
I normally point people towards JME in the states for "off the peg" cams, which can be beyond the spec's of a custom grind and hardening of standard cams as blanks, or some something custom ground from a billet I would use a place in France which manufacture cranks and camshafts from scratch, but the cost of that is about £2k (!!!)
If Augment are getting good results with their cams, then that should certainly be something to investigate, as I am a great believer in buying British wherever possible as well as buying whatever is the best product available.
It may be worth talking to the race series organiser, as I know some series have the letter of regulations, but also a more flexible spirit of regulations, in which case they are happy about different engines being used, such as a 968 engine in a 944, as they can be linked as spiritual versions of the same car.. However your CC grouping is something they will not generally make allowances for.
If Augment are getting good results with their cams, then that should certainly be something to investigate, as I am a great believer in buying British wherever possible as well as buying whatever is the best product available.
It may be worth talking to the race series organiser, as I know some series have the letter of regulations, but also a more flexible spirit of regulations, in which case they are happy about different engines being used, such as a 968 engine in a 944, as they can be linked as spiritual versions of the same car.. However your CC grouping is something they will not generally make allowances for.
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