heinrich

How does one make one's tyres rip loose at every application of the throttle? By fixing the little things. The horsepower secrets of the Porsche 928 are very subtle, and they all have to do with very simple things. Most importantly, if there is anything wrong with the car's performance systems ... then it will make a huge difference. I fixed a little thing yesterday that had been bothering me since I installed the engine, and it made a HUGE difference. I have seen this so many times, I should have thought about it.

Go back to basics, they really work. And they are cheap.

blown 87

Not getting full throttle?
What did you do?

heinrich

The point isn't what I did yesterday. I posted this because every time I fix a small thing related to power, it makes a massive difference. Idle unstable? Hunt it down. Plug wires crusty? Replace. Vacuum system not functioning? Fix it. Etc etc etc etc

the flyin' scotsman

Add a supercharger?

Seriously, my car has never ripped the tyres loose and believe its running well, I think. I've always thought that it was the advances in new tyre technology that can now handle the horse power............perhaps there something basic amiss

blown 87

From what I have seen about cars in general, they are always a work in progress.
I try to do every thing i can think of before I really start to drive a project car, then take little small test drives to find out what else needs to be done.
It is almost like it never stops, but for the most part I think I have been lucky with my approach. I make a master list first of the obvious and pretty much go thru the car.
Then the detail list of small things that crop up, and once I have everything off of both lists I can usually get a couple of years and maybe 20,000 miles before something breaks other than just maintanece. I have gotten lucky on the last couple of them, the Supercharged Corvette was the last one I have finished and it has went more than 2 years with no problems so far.
I hope to be this lucky with the 87 S4.

worf928

I have to agree with H-man. Every time I hear or read about an owner looking for a 'few' more horsepower and contemplating an X-over, or chips, or losing the CATS, I have to bite my tongue. Not that more power isn't a good thing - just that some folks want to spend dollars on upgrades before spending dollars to make sure what they have is working right.

Chance are there are at least 30 horsepower available from just getting the car back into near-factory running condition. The vacuum system, breathers, and basic maintenance items (injector cleaning, plugs, wires, fuel filter, etc.) are usually 75% of the battle. I'd bet an x-pipe that 1 out of 2 928s out in the world have a vacuum or breather problem that's stealing power. I've yet to have one brought to me that didn't have a vacuum problem of some sort. I'm startled by the number of 928 owners I talk to (not so much folks on this forum) that don't know when their fuel filter was last changed. Or when their O2 sensor was last replaced. Or plugs. Most don't have records that go back more than a few years - if any - prior to their ownership. There's no maintenance baseline to use as a diagnostic guide.

Dannyfumi

What are some of those little things??

Dan

John Speake

Knock and Hall sensor faults very often go un-noticed, because they don't make any difference in many driving conditions. Often it is only the "hard" drivers who realise that something is amiss. Usually when they can compare directly with another 928. But for many of us this is not often possible. These faults retard the igntion by 6 degrees at higher throttle openings.

A large proprtion of the 928s that visit me have knock/Hall sensor faults.

An Aged MAF will definitely blunt top end power and throttle response. If your car has more than about 75k miles, try swapping out for a known young one.

I agree with Dave C. Cleaning the injectors on my car made a big improvement in performance.

Perhaps there ought to be a "75k" check list ?

Ultransonically clean injectors
Change O2 sensor
Change Temp 2 sensor.
MAF check
Other ?

Brett928S2

[QUOTE=John Speake]

An Aged MAF will definitely blunt top end power and throttle response. If your car has more than about 75k miles, try swapping out for a known young one.
QUOTE]

Hi All

I totally agree with John about changing the MAF....

Due to my (cough) small Nitrous explosion...my MAF was toast

New one from John...and an amazing difference....tickover was smoother...mid range was much more powerful and top end was better.....overall it was MUCH crisper...

The only other tip I would HIGHLY RECOMMEND to ALL auto box owners is a kickdown bypass switch....for a couple of $ or £ ...its the BEST improvement by far...............

All the best Brett

PORSCHE 928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS, KICKDOWN SWITCH.K&N.NITROUS KIT 150 HP.
PCGB UK 928 FORUM MODERATOR - Email managingdirector@pchealthcare.co.uk

blown 87

I guess that is just a lot better way of saying what i was trying to say, make what you have work first.

I have vacum leaks on mine, this will be the next step after I recover from doing the TT and all that goes with that.
I have allready been buying parts for this, new knock sensors, new hall effect, still need a lot of more parts before I go there.

I am in agreement with "H" and you on this.

IcemanG17

H is totally right

I drove and 87 5 speed that was for sale a few months back......I was expecting it to feel stronger than my 88 auto.....it didn't...it felt kinda flat.....turns out the 4 way vacuum "T" wasn't connected (think huge vac leak) so the flappy wasn't working.....hence a "flat" feeling around 4K rpms.....& the O2 sensor might have been going bad causing an over rich condition (could smell it out the exhaust + the PPI said the plugs were too dark)......my guess is this particular 928 was about 20hp down on stock performance.......but it still was fun to drive!! The new owner has corrected all these problems!

John Veninger

One way is crappy tires and some rain

I like the stroker approach

heinrich

plugs
wires
rotors
caps
intake
exhaust
vacuum
fuel
injectors
coils
battery
battery connectors
maf
throttle cable
fuel filter
air filter

Those are the basics of making power on a 928

heinrich

JV I have 19's with Yoko AVS Sport 265, they stick just fine till Godzilla tears them and the road surface asunder

SharkSkin

Ooohhhh no.... there goes Tokyo...