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Hartec 3.7

giraffeinbath

Silverstone
Joined
23 Mar 2011
Messages
128
I've been pondering this for a while, mentally forward planning what I may spend the toy budget on over the next few years...

I've no reason to expect my motor needs a stripdown currently but as it's approaching 120K it may be on the horizon at some point if the car is a keeper, which I suspect it is.

If my hand was forced into a full ££ rebuild by necessity going the extra for the Hartec CC increase seems like a no brainer, but there's also a good case to get the motor rebuilt before it breaks and enjoy the peace of mind and extra performance of a feshly built Hartec conversion whilst there is still fuel in the pumps.

There are a few threads around from owners who have had the Hartec 3.6 to 3.9 conversion done, but very little online feedback regarding the 3.4 to 3.7.

Anybody here running a 3.7 Hartec rebuild, how do you like it?
 
watching this with interest. I am considering a 3.9 for my close to 150k 3.6.
 
crash7 said:
I have a 3.7, I did start a thread but have not updated it in quite sometime, may be of some use.

http://911uk.com/viewtopic.php?t=134930&sid=76883b55960598939b3998ad2a0297f1

That's a new thread to me, just read it all the way through. There's some interesting analytic stuff in there with the challenges of gains on a 3.4 over starting with a 3.6, no doubt starting with a 3.6 makes more sense but I'm with you in preferring my gen 1 ;)

Looking at it from a more emotive perspective, how do you find the 3.7 on the road compared to the previous 3.4 incarnation?
 
Yes that is an interesting link which I have only had time to scan through quickly.

One point that often arises (which is a bit weird) is that just because the bottom end and mid range are noticeably improved (by about twice the increase in capacity around 15%) there is an assumption that this is at the expense of top end (which it isn't).

The top end is up by around the same as the capacity increase (9%).

This means that you always have accelerating power around 9% better but even more than that if you are accelerating from moderate revs and usually without needing to change down (as you used to).

With a general increase in engine efficiency and economy of around 10% as well - there really is no down side.

If on the other hand you found another way to increase the peak BHP by 9% you would usually find the bottom end and mid range lower than standard and be having to thrash the engine to get it to perform and it would be less economical.

It's a strange phenomenon which I am also encountering when describing our Eco-Power invention to selected people who have signed the NDA (at this point). Because it improves the economy (and reduces emissions) even more - people seem unable to hear me also mention that it is also more powerful throughout the rev range (commenting that they are not sure people would sacrifice performance for the benefit in green house gas emissions) - just as if they didn't hear the comment about also providing better performance (or perhaps they just cannot believe it possible?).

I guess this is what people went through when they tried to persuade others the earth is not flat etc.

We limit the 3.4 996 to a capacity increase of 300ccs because of the limitations of the std cylinder head that was used in the 3.2 Boxster S but the Cayman S 3.4 has the later 3.6/3.8 head and so we can get similar improvements throughout the range up to 3.9 (or a 500 cc lift).

Sorry if we are a little slow answering the enquiries at the moment - very busy producing them and summer holiday time - but we will get round to answering all enquiries. If you have not had yours by September 15th please E-mail me directly.

Baz
 
I'm still seriously considering this although now unfortunately from the perspective of my motor having grenaded itself since my first post on this thread :roll:

On the off chance, is there anyone on here in the Bath/Bristol/Swindon (or general South-West) region running a 996 with the Hartec 3.7 conversion who would be willing to hook up, take me for a quick spin as a passenger and share their experience with it?

Obviously if anyone is brave and willing I'd also really value the opportunity to jump in the driver seat on a quiet road for 5 minutes but I appreciate that's a big ask.

Basically I'm struggling to gauge how the general feel and torque of the 3.7 would compare to the standard 3.4 or a 3.6 from a 997 which are the only comparisons I can draw upon currently from experience. I think literally a couple of minutes would be all it would take to get a first impression; reading comparative figures on paper doesn't really mean a great deal, ultimately there's no substitute for the bum dyno...
 
giraffeinbath said:
I'm still seriously considering this although now unfortunately from the perspective of my motor having grenaded itself since my first post on this thread :roll:

On the off chance, is there anyone on here in the Bath/Bristol/Swindon (or general South-West) region running a 996 with the Hartec 3.7 conversion who would be willing to hook up, take me for a quick spin as a passenger and share their experience with it?

Obviously if anyone is brave and willing I'd also really value the opportunity to jump in the driver seat on a quiet road for 5 minutes but I appreciate that's a big ask.

Basically I'm struggling to gauge how the general feel and torque of the 3.7 would compare to the standard 3.4 or a 3.6 from a 997 which are the only comparisons I can draw upon currently from experience. I think literally a couple of minutes would be all it would take to get a first impression; reading comparative figures on paper doesn't really mean a great deal, ultimately there's no substitute for the bum dyno...

Sorry to hear that, that was quick considering you mentioned the car being ok just 3mths ago.

Where there any signs? What do you think happened?

My cars done 180k so a little nervous now
 
The Baron3 said:
giraffeinbath said:
Where there any signs? What do you think happened?

I think it broke ;)

The bottom end's gone and I'd say the signs weren't as obvious as you'd expect. I don't want to turn this into a negative scaremonger thread as I'm looking for some constructive help, but at 180k I think I'd be keeping an eye on things with oil analysis and being open minded to the idea of a preventative bottom end rebuild sooner rather than later. Ironically I was literally about to change the oil and send off a sample with the Millers kit, the oil and service parts are sitting in the fr'oot ready for the job. If I'd been just a month earlier I may have caught it before it went bang. C'est la vie...
 
giraffeinbath said:
The Baron3 said:
giraffeinbath said:
Where there any signs? What do you think happened?

I think it broke ;)

The bottom end's gone and I'd say the signs weren't as obvious as you'd expect. I don't want to turn this into a negative scaremonger thread as I'm looking for some constructive help, but at 180k I think I'd be keeping an eye on things with oil analysis and being open minded to the idea of a preventative bottom end rebuild sooner rather than later. Ironically I was literally about to change the oil and send off a sample with the Millers kit, the oil and service parts are sitting in the fr'oot ready for the job. If I'd been just a month earlier I may have caught it before it went bang. C'est la vie...

Thanks for that, I'm just down the road from you, so will interested to see what you decide as you maybe using similar expertise as we are so local to each other
 
giraffeinbath said:
I'm still seriously considering this although now unfortunately from the perspective of my motor having grenaded itself since my first post on this thread :roll:

On the off chance, is there anyone on here in the Bath/Bristol/Swindon (or general South-West) region running a 996 with the Hartec 3.7 conversion who would be willing to hook up, take me for a quick spin as a passenger and share their experience with it?

Obviously if anyone is brave and willing I'd also really value the opportunity to jump in the driver seat on a quiet road for 5 minutes but I appreciate that's a big ask.

Basically I'm struggling to gauge how the general feel and torque of the 3.7 would compare to the standard 3.4 or a 3.6 from a 997 which are the only comparisons I can draw upon currently from experience. I think literally a couple of minutes would be all it would take to get a first impression; reading comparative figures on paper doesn't really mean a great deal, ultimately there's no substitute for the bum dyno...

Sorry to hear this.
 

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