recovering lost BHP

[Eldavo]

Another vote for the throttle response cam here, £15 off eBay. Haven't found it makes the car jerky at all, even in traffic. In fact, it makes the throttle response much more akin to my Audi A3 daily driver so I find it much easier hopping between the two.

 

[Eiger]

ORIGINAL: pauljmcnulty

Simply put - How can you recover lost bhp?

What makes you think you've lost any horse powers?

Barring any major problems, it's a pretty unburstable engine. The weak points are the ignition parts, with the leads, rotor arm and dizzy cap often well past their best.

Nothing in particular really Paul just a general impression I got from reading various forums lead me to believe that the bhp can seep away over time as things get worn in the engine. I've read some almost horrific posts on hp being down to near 100hp - I certainly don't feel like my 944 has lost anything near that.

I'm actually looking forward to tackling all this servicing this weekend - Opie are sending over a bunch of goodies and I'm picking up a Dizzy, Rotor & Leads from GSF tomorrow.

I'm undecided on plugs though - any recommendations?

Then I'll be looking for somewhere to do a dyno here in southern hampshire. Where tho?

 

[barks944]

I'm one of the ones that never really like the throttle response cam. Personally I think you should just push the throttle harder! Also you get less control at the low throttle positions which I found useful. I think I have one in the garage somewhere if anyone wants it?

 

[JamesO]

With the bhp loss on a 8v, good ignition parts as has been said and making sure the cam timing is spot on, can be a tooth or so out and still run apparently (not tried this).

Assuming you have good compression, spark and air to fuel ratio it should still be pretty close to the factory output.
I'm led to believe that 16v cars tend to lose the most power as they age through incorrect cam timing and play in the valve guides (due to long valve stems??).

 

[Mike_Pollock]

My '83 with a supposed 120K '86 engine put out 148 at a dyno which was probably reading less than most people were expecting!
That was with new ignition bits, which had had a noticable beneficial effect, noted beforehand.
I would say that if the plugs look good, a compression test to check and then new ignition bits should put back most of whats possibly missing.
Mike

 

[Pete917]

ORIGINAL: madrob6

Getting the injectors cleaned probably wouldn't go amiss either. That and checking all of the ignition and fuelling components are working properly.

+1 for this. Its cheap to get them calibrated and will make a huge difference.

 

[Eiger]

do any garage do this or must I seek out a specialist injector technician?

 

[Pete917]

Normally its more of a specialist job as they need a fuel rig to calibrate the injectors. I think I paid something like £15 per injector. A lot cheaper tan £90 eac new.

 

[barks944]

Is injector cleaning the sort of thing you would find all over the place or does it need to go off to a specialist hidden away somwhere?

 

[ukmastiff]

If you are happy to spend various cash on bits to 'recover ' BHP isnt it worth putting the car on a rolling road first to find out how much you may or may not have 'lost'

Just a thought

Mas

 

[Pete917]

A baseline would be good. Have a quick BHP run to see where you are. You be recovering or adding new BHP []

I used a company called Wrightune who I believe take it somewhere......

 

[pauljmcnulty]

If you are happy to spend various cash on bits to 'recover ' BHP isnt it worth putting the car on a rolling road first to find out how much you may or may not have 'lost'

Just a thought

If you're actually worried about improving from, say, 159 to 163 BHP, then yes. I'd still look at it from a completely opposite viewpoint. We all know how sensitive the cars are to geometry, I'd suggest that a proper 4-wheel alignment would be likely to result in far more real-life driving improvement than a dyno run, for instance.

I'd go back to my earlier comment, asking why he's concerned that the car is down on power. Steven's reply was:

Nothing in particular really Paul just a general impression I got from reading various forums lead me to believe that the bhp can seep away over time as things get worn in the engine. I've read some almost horrific posts on hp being down to near 100hp - I certainly don't feel like my 944 has lost anything near that.

I'm pretty sure this car has no real power issues, and nothing more than checking or replacing the usual service items is going to make a big difference. Let's be realistic here, tyre pressures will have a far greater effect on performance than the odd few horse powers.

 

[Eiger]

ORIGINAL: ukmastiff

If you are happy to spend various cash on bits to 'recover ' BHP isnt it worth putting the car on a rolling road first to find out how much you may or may not have 'lost'

Just a thought

Mas

Mas didn't you have a DYNO nightmare somewhere or am I confusing you with someone else?

I plan to have a dyno run after doing all the service items (dizzy, rotor & plug leads etc) and an injector clean as suggested here, just to see where it is on bhp compared to original spec - hopefully that won't yield any major disappointments ... it will be an interesting outcome either way. I know it's not a lot compared to the Turbo or S2 but I may as well know what this little porker is putting out 24 years down the road.

Then suspension & steering bush renewal is next to sharpen up the handling, followed by a geometry check as Paul has said.
(Admittedly I'm starting to think about a SPAX suspension kit now too ...)

All the feedback here is giving me a good few steps to follow. Thank you all for your input.

 

[ukmastiff]

No that was me , wouldnt say nightmare though. If anything it proved the need for a dyno run. I went in thinking the car was running fine but clearly it wasnt , so finding that out alone was worth the 50 quid or whatever it was. The car was running super rich due to a boost pipe being loose and th AFM being out of sorts. From what I read many old 944's have AFM's which could do with replacing but rarely are.

I'll admit my bottle was flapping a bit when I came out though lol , and he did make the car worse than it went in. However Promax now have it running superbly. I just wish people like Promax had their own dyno's then we really would have a one stop tuning shop. I suspect thwt is why chipwizards are so popular as they have expertise and dyno under one roof but they are far too ooop North for me.

Cheers Mas

 

[dirtydirtyharry]

I wasnt aware that the throttle reponse cam was circular until I read this thread. I now know that my lux already has a throttle response cam lol! I presumed it was circular as standard. May have to get it chipped instead after all!

 

[sawood12]

Eiger, with these cars getting on now it is probable that alot of the engine components are probably way past their best. Before you spend any money on 'mods', if I were you i'd systematically go round the engine and replace all the components that might have an effect on engine performance and efficiency. This will include the electrical system right back to the coil, and maybe even the coil if you're feeling like taking a belt and braces approach, along with all the other recommendations and i'd include an AFM refurb in this too. Only when you know your engine is running as well as it can be in stock trim then you'll be able to make a true evaluation as to whether you think you want to or need to start looking to mods.

It might also be worth doing a compression check. If you've lost compression due to leaky cylinder head or HG then you are wasting your time chasing more horses with mods until you sort out the fundamental problem causing loss of compression.

 

[Pete917]

Plus one for the compression and leakdown test.

 

[peanut]

the easiest and cheapest performance improvement to be had by far is simply to drastically reduce weight.

Remove anything that isn't essential especially spare wheel, tools, junk in the boot, jacks etc, maybe think about seat motors ? especially passenger seat motors if its rarely used . I bet you could reduce the weight by 50kgs without trying too hard. Carry a couple of puncture /repair/inflate cans or use run-flat tyres

What will that do to your power to weight ratio ? no idea . I'm sure one of the track day racers can work out the sums.

Next as others have said ,the varicam is an excellent upgrade. it feels much more responsive than stock.

Next I wouldconsider getting the ECU chipped. Easy power to be had obviously at the expense of economy.

Use only premium rated fuel.

Lastly as others have said a thorough service and tune up especially the ignition system and renew all the battery terminals cables and earthing points.

One last thing reduce the weight of the wheels and or use a lower profile tyre which will give faster acceleration

 

[sawood12]

I'm not a fan of the weight loss plan for a road car. You can't loose that much weight on these cars as the majority of the weight is locked up in components you simply can't ditch. Taking 50kg's or even 100kg's out of a 1400kg car is not going to be noticeable. I didn't notice any real reduction in performance with my 944 when I had a 90kg ish passenger on board. By ditching the nice things in the car is only going to make it less comfortable and make you not want to drive it as frequently. In anycase a GT3 is around 1400kg's anyway so you can achieve stunning performance with a car at stock weight.

 

[dirtydirtyharry]

ORIGINAL: sawood12

I'm not a fan of the weight loss plan for a road car. You can't loose that much weight on these cars as the majority of the weight is locked up in components you simply can't ditch. Taking 50kg's or even 100kg's out of a 1400kg car is not going to be noticeable. I didn't notice any real reduction in performance with my 944 when I had a 90kg ish passenger on board. By ditching the nice things in the car is only going to make it less comfortable and make you not want to drive it as frequently. In anycase a GT3 is around 1400kg's anyway so you can achieve stunning performance with a car at stock weight.

Ive got to concur with this. I recently stripped out virtually everthing other than the drivers seat to sort out water leaks and have a good 'butchers' around the car. I thought at the time that it was more responsive as a result of the weight loss but having added a LOT of dynamat and new carpet underlay prior to adding all the interior trim again I have since been for a spin and its no different, its all in the mind (unless of course you are using it on a track).Its now far less noisy and a much more enjoyable drive.

Im in the same boat re wanting to increase power. I dont want to do so at the expense of comfort or economy tho. Something probably has to give unfortunately altho some people say that getting the superchip doesnt harm economy. If thats true then my mind is probably made up! []