Porsche Enthusiasts Club Forum

without going too mad, what can be done to 968 engine to increase power. must be kept n/a (no turbos/supercharging)

are there chipsets out there or remaps etc, along with maybe custom exhaust etc?

what is do able

cheers

As I understand, there's very little that can be done to the engine. The promax 7100 chip gives a smoother power delivery, I found. I've also done the airbox mod, and fitted a K&N filter to improve breathing..... Also fitted a promax cat back exhaust , but that was only cos my original one had rattlely baffles.

Ditto Promax power kit. 968 engine management is quite different with no interchangeablity with the S2. Tried the Scanvision MAF kit but doesn't work to well unless it's a warm track day.

A chip, i've had the Promax, RSBarn stage 1 and currently have RSBarn Stage 2.

The most power gains (if you can call it that) are from a head rebuild. A 24 year old car is probably getting a bit near the mark on the head gasket. If you get the head rebuilt you'll get back to 240 ish. You'd be surprised but most are down to 200 or below.

Air box mod I don't believe does anything except give a nice noise.

Other than that you are into big big money, NA 968's have got to 280 and still be road driveable but budget 10-12k See EMC's website and Lali's old 924 with 968 running gear).

Interestingly i have a SciVision MAF kit on my turbo and it performs well in all conditions, hot/cold engine, hot/cold day. Yes it has limitations as it emulates the AFM signal but its a massive step forward from the barn door AFM. I have an AFR gauge and my car is sweet as a nut and fuelled efficiently through the rev range. It also reduces lag and flows more air.

Obviously my car is a turbo but would have no reason to believe a correctly installed and working SciVision would not benefit any AFM equipped car.

Stuart

A good air flow is important - my 944S2 went a lot better with the K&N filter and removing the baffle filter housing plate within the airbox (not sure if they were the same ie 968 under the front panel). A decent stainless exhaust with a larger bore mid box, which I did on mine also helps. But I don't have cats - not sure if you can take them off re the MOT...

Dave

K&N filter will make 0.5 bhp more in real life driving/road conditions. No baffle filter etc.

It has honestly been tried every which way. A chip does improve things but don't expect night and day difference it's more just 'drivability'.

Your car will be down on power and the only way to get that back is a head refresh with all new valves can be 40bhp or more. Outside of that, get a complete engine rebuild done by EMC and you'll get towards 270bhp but then you are probably looking at 8k.

Otherwise a 3.0l Turbo will do and something i'm aiming for, but then you are in for more money than the cars worth in all likelihood.

I'm tempted to look into keeping NA but moving it out to a 3.2, gotta make more power right?!

Just found an old Pheads thread with a few interesting comments about S2s and 968s, evidentlty the heads were designef for turbo induction and have rather large inlet ports which do not work well for NA. Porsche decided not to pursue the turbo application as they were outperforming 911s. So as I feared more power from a 968 or S2 would involve a large financial investment or a cheap supercharger. As our cars become less and less common I'm quite happy to keep it reasonably standard and in good tune. They are no sluggards and the looks are just sublime compared with the SUV's that populate our roads.

Nots sure about that, but the 968's are known to suffer valve and guide wear which robs it if power by as much as 40-50bhp or 20%.

If it's not had a head rebuild the head gasket will be getting marginal and may as well get the power back whilst you are there, some of the valves are expensive though, think the exhaust one's are getting towards £100 each.

Hi, Your spot on with the Actual output's as I've driven 3 and owned one for a year and the differences are quite substantial.
Mine had done approx. 120K, and I drove a CS which had only done 70K but it was sluggish.

I did fit a set of new leads, Denso Iridium plugs and an RS Barn chip all in one go and it did feel more punchy in the midrange, also
the top rpm possibly a little cleaner etc.. and I bought an airbox from the bay already cut with trumpets...

I know a lad who's races a 968 in the CSCC modern classis series, he was running approx. 285bhp then he went to a pressurised airbox, ITB's and a different ECU I think and he's now over 320.

He would be able to advise what options you may have for more ponies, he's just built me a 2.7 8 valve N/A engine this year which churned out 205bhp & 205 Ft Lb's.

This pulls strong fitted to a 1040kg lightweight 924S I've built over 3.5years!

R

Very interesting, be particularly interested how he got 285bhp out of a N/A 3.0l 16v 968? The most i've seen is 270.

Mine was night and day after the rebuild and despite not being the best driver it certainly pulls away from other 968's (that haven't had a rebuild). Timing is very important and it never ceases to amaze me how many have their timing less than perfect.

I've often thought ECU/Motec etc could make a difference, a 3.2 N/A would be amazing.....

I think higher lift cams and head work, probably more it's a fully caged Racecar so the quest for higher power
with a higher RPM band will of probably sacrificed the low and mid range rpm drive ability.

No Cat i'd say also and like mine some very trick Live Mapping.
From the first to last dyno run (Approx 15 runs) I gained 26bhp from over 6 hours work!

I can ask, although I suspect some might be secretive also.

R

Having watched recently an old Top Gear where they drove a Ferrari 308, Lambo and a Maserati - all quite old - but each were put on a dyno to check bhp and each performance demise, over time any miles/usage from the factory standard and thus was proved. The problem with wanting 'bolting on or go faster/modifications' bits are useless, unless your stock engine unit is performing at it's best from the get go, ie get a dyno done first, thus giving you an initial 'bench mark' to start any modifications from...?

im in a similar position right now,
my 968 powered 944 may well need an engine rebuild subject to investigation.
after several years of being mucked about by two different specialists, I'm keen to get this done right this time.
and if I'm in for a penny Id just as well go in for a pound and try and tease a little extra HP out

I've considered the supercharger route, but am equally interested in keeping it NA.
look forward to hearing more