[engine_work] Project Sarty

[welshpug 1,657]

when I had a brief drive of it just tickling along some side-roads it felt so nice to drive, just light pressure on the (at the time quite sensitive!) pedal and you just picked up pace without any fuss or noise, I can't but imagine what its like to open it up properly!

 

I like the fact that its a car you don't have to screw the knackers out of to get punted along at a fair pace

[Bonzai 2]

so have you had it running with the trumpets, or are you wiating for the filter to arrive? id be intrested to hear the sound difference, if its anything like what i expect it will be farkin lovely! I absolutely cannot wait to hear the results from Feb 9th!

[DrSarty 90 1 Cars]

Maxi>

Sorry to hear about your forum woes, and thanks for the figures and comment. Most interesting.

 

As for the lust for torque, it pretty much boils down to the debates of late (or which have stood in the motoring world forever) about torque and horsepower.

 

I'm not wanting to start the debate here again, but my opinion is that a BHP figure is something you kind of just end up with. Let me explain. F1 cars operate at high speeds most of the time, and whilst they 'only' produce 250lb/ft or similar, the engines are designed to do this at 14-18,000rpm, as those RPMs best suit the super light car on typical F1 style tracks, where a great deal of inertia and therefore energy is available to deliver to the road (and this is the most important bit) at the already relatively high speeds they are travelling, e.g. 90mph round a hairpin in 1st gear. This 800-900 horsepower (in F1) is simply a reflection of that energy available, but in turn is just a mathematical function of torque x rpm / conversion factor.

 

Still, 250lb/ft IS a lot of torque, when a car weighs around ~500kg.

 

So what I'm saying is, that an engine simply generates torque, and nothing else usable.

 

To that end - and what Meirion (WP) said really - is that high peak AND high average torque, and in particular the peaks of torque and BHP being pretty close together, delivers a very driveable car.

 

In the 'torque vs bhp (again)' thread, there is a link to an excellent 'torque vs bhp trade-off' Word document (you could search for this) that explains this extremely well. Instead of 'drivable', it says 'sweet ride'.

 

So, in short, if I aim for an engine which delivers fat torque early on, which doesn't really climb that steeply but stays up high on average, and the peak torque figure is somewhere around 4.5k and the peak BHP arrives 5.5-6k, then you end up with a highly tractable road car. And that's really the point: IT'S A ROAD CAR.

 

As you know, (and I keep shouting), tailoring the torque curve is what changes the character of the car, whether that is done by altering the extent of the total or usable rev range, and/or tuning the engine to deliver the torque in a different fashion.

 

If we see my peak torque perhaps of 190lb/ft at 4,800rpm, I may end up with a peak bhp at 6,000rpm (with a guess of torque of 175lb/ft) of 200bhp. On the other hand if I get the same peak torque at 6,500rpm, I end up with 216bhp, the same as your 2.1

 

I personally would be happier with 200lb/ft at 4,800rpm, because it would perhaps mean torque staying up at around 185lb/ft at 6,000rpm, which would still ONLY mean 211bhp, which doesn't sound that great but means the more tractable, road-driving car I was always after. Just to make the point, if we move the peak BHP point up the rev range, to say 6,500rpm (speculated torque of 180lb/ft), we get 222bhp, which is a nice, higher figure, but to me, that's all it is, and I've have to work the engine harder to get at that 'power'.

 

This means I don't really care what BHP figure I end up with, it's the torque curve being the shape that I want it.

 

Maxi> I hope that waffle answers your question.

Edited February 3, 2009 by DrSarty

[kyepan 291]

Rich,

 

With the stage 2 cam and rev limit and compression, this car is going to produce higher peak power than in it's previous state of tune. IIRC the other highly tuned 2.2 produced near 230, and the special sandy one a bit more. You're sandbagging if you think it's going to produce less than 220 with that setup.

 

Hopefully you're peak torque won't be bumped up too high with the new cam setup, because I completely agree that keeping the mass of the torque in the normal driving range is the best plan for a road car.

 

PS, may be joining you on the rebuild train soon, it's time to learn how to build engines.

 

J

[DrSarty 90 1 Cars]

Rich,

 

With the stage 2 cam and rev limit and compression, this car is going to produce higher peak power than in it's previous state of tune. IIRC the other highly tuned 2.2 produced near 230, and the special sandy one a bit more. You're sandbagging if you think it's going to produce less than 220 with that setup.

 

Hopefully you're peak torque won't be bumped up too high with the new cam setup, because I completely agree that keeping the mass of the torque in the normal driving range is the best plan for a road car.

 

PS, may be joining you on the rebuild train soon, it's time to learn how to build engines.

 

J

 

Totally agree J.

 

In fact (and rather ironically after my above waffle), the cam advance on the inlet PLUS the cam retard on the exhaust cams (the stage II & I respectively when fitted), will actually shift some of the power up the band, so it is a little more spread, so we can benefit from climbing above 7,000rpm.

 

Don't forget, it sat at 7,600 quite happily on the rollers last time!

Edited February 3, 2009 by DrSarty

[maxi 36 1 Cars]

From what I have read Rich, you are making a lot MORE torque than I am with my engine. With your figure, do you not find its forever breaking traction and more to the point drivetrain parts?

 

Maxi

[DrSarty 90 1 Cars]

Well, we shall see.

 

You have a lot more experience than me, and that's bound to show.

 

I'm still worried at this stage of bore-washing, now I understand what it is. You warned me of this, and 3 times now, mainly when it's very cold, it's started running as if on 3 cylinders (a bit lumpy) for a while, but then has cleared.

 

Only this time it hasn't cleared, although it is clearing. I'm just down to see what the plugs are like. I suspect (read: prays with fingers, toes and testicles crossed), that they're just s*itted and sooted to f*ck, but I am resigning myself to the worst possibility and hope to be proved wrong.

 

If I have lost compression due to this, then I can honestly say you and others warned me, and I will eat a very large slice indeed of humble/embarrassed pie.

 

Dave at Emerald and Anthony said that if I was sensible (that's why I've imposed the no WOT & 4k rule on myself) then there shouldn't be any danger of it happening. However that doesn't stop me crapping myself right now.

 

We shall see.......#gulps#.

Edited February 3, 2009 by DrSarty

[maxi 36 1 Cars]

Well, we shall see.

 

You have a lot more experience than me, and that's bound to show.

 

I'm still worried at this stage of bore-washing, now I understand what it is. You warned me of this, and 3 times now, mainly when it's very cold, it's started running as if on 3 cylinders (a bit lumpy) for a while, but then has cleared.

 

Only this time it hasn't cleared, although it is clearing. I'm just down to see what the plugs are like. I suspect (read: prays with fingers, toes and testicles crossed), that they're just s*itted and sooted to f*ck, but I am resigning myself to the worst possibility and hope to be proved wrong.

 

If I have lost compression due to this, then I can honestly say you and others warned me, and I will eat a very large slice indeed of humble/embarrassed pie.

 

Dave at Emerald and Anthony said that if I was sensible (that's why I've imposed the no WOT & 4k rule on myself) then there shouldn't be any danger of it happening. However that doesn't stop me crapping myself right now.

 

We shall see.......#gulps#.

 

 

Im not trying to pick holes Rich, I just wondered what the fascination with torque was, thats all. I openly admit I have a fascination with peak BHP and I have my reasons why, which work for me. Its all about what you want from your car.

 

As for bore washing, is it smoking blue at all? To be honest, I would stop driving the car immediately to prevent any further damadge. Im no expert on rings and the finer points of engine building (I have bolted several engines together before but I am by no means an experienced engine builder) but im pretty sure the rings will bed back in if its not been bore washed for too long. Fingers crossed for you mate!

 

Maxi

[Tom Fenton 1,542]

If the fuelling hasn't been changed, and the new inlet arrangement is more efficient than the old, then if anything it will be running lean.

[maxi 36 1 Cars]

This topic has gone on so long ive completely lost track of even what engine its running to be honest...... Isnt it now running larger injectors or something?

 

Rich, didnt Sandy or whoever made the inlet advise you whether to drive it or not (from the aspect of it will massively alter the fuelling etc, not trying to blame anyone before people start jumping down my throat as per usual)?

 

Maxi

[DrSarty 90 1 Cars]

Summary for Maxi:

2187cc from XU10 block 87mm over-bored with 92mm stroke diesel crank. Wiseco (or maybe JE) custom pistons running 11.6:1 comp.

 

It was originally mapped with a homemade manifold that had a rather steep, angled (i.e. not curved) entry to the head. The GTI 6 injectors (which I still run to show injector size hasn't increased) were in the throttle bodies, approx 15-16" away from the head. Dave had to map slightly rich to cope with fuel drop out caused by distance and the fact that the inlet runners were slightly up hill.

 

The bodies were attached by a silicon hose join each, which wasn't exactly tight and secure as a nun's proverbial, and I'm sure the sponge seal inside (yes), was soaked in petrol when they were removed. As I used to say in my signature, 'it wasn't really ready'; you're damn right.

 

In fact I think it was you who said don't drive it, plus maybe one more. So you could've been right.

 

The above set-up still made 188lb/ft and 196bhp.

 

The new set-up has larger bodies (46mm instead of 40mm), and as Tom has alluded too, this should mean more air, leaning her up a bit.

 

But now the GTI6 injectors fire straight onto the backs of the valves and are cleaned and tested injectors, so perhaps the result as has just been shown by me removing the injectors tonight is still too much fuel. They were sooty and black, and cylinder no1 was slightly wet, but I suppose that could've been due to the stroke it was on......or a bum piston seal. But I don't think so as it fired up no probs and was pretty much back to normal, although I haven't been out for a blat yet due to playing father.

 

To answer your question, no, there's been no smoke. Occasionally a puff of black/dark smoke on reapplying the throttle after run-down, but other than that, just a sooty tailpipe.

 

She now has new plugs in again, and will get another brand new set for the map, as well as a new Bosch, ECU coolant temp sensor, just to ensure we are 100%.

 

I think I'll still run a compression test this weekend, but I'm (perhaps unnecessarily) dreading the results.

 

Bottom line is, if I've fubar'd it it's my fault and we'll wang her out again, rectify any issues and rebuild her with the new cams and staged injectors. I could be off to Afghanistan again for a year if I get this new job, and I'll have the opportunity and the wonga to do it.

 

Thanks for your advice and concern everyone. And I mean that. My stomach's in knots...

Edited February 3, 2009 by DrSarty

[hexhamstu 9]

ah thats make it alot clearer, i wondered why it would be running richer instead of leaner. now i understand! good luck with the engine!

[maxi 36 1 Cars]

If its not smoking, I wouldnt worry. But Rich, for the love of god, please buy a s*itter and drive that until this is mapped! Seriously, you really are playing with fire mate!

 

Maxi

[taylorspug 7]

Agree with that ^^

 

In fact when Maxi was running in his new engine, from following in my car it would puff the odd bit of black smoke, indicating it was getting plenty of fuel, but IIRC when it went on the rollers it was very lean, and that wass on the map from the old engine, so wouldnt have been a million miles out. Bottom line is if you arent totally sure dont try it, you will be kicking yourself when you are scudding around taking the engine back out due to a preventable failure.

Edited February 4, 2009 by taylorspug

[DrSarty 90 1 Cars]

All wise words & thanks.

 

She ran beautifully again this morning.......although the oil pressure gauge has packed up.

 

It did this yesterday, but then sprang back to life, so it's incredibly likely that it's a leccy gremlin.

 

Just to clarify, I must take my son to school (2 miles then parked) and there are only 5 days left before we get remapped. The oil will be dropped & refreshed before Monday and the oil pressure gauge will be working perfectly again. If I had a month to wait, I'd buy a s*itter. That said, still great advice.

 

It will be driven to Emerald with due diligence, and then we can hooooooooooooon.

Edited February 4, 2009 by DrSarty

[Anthony 1,003]

Dave at Emerald and Anthony said that if I was sensible (that's why I've imposed the no WOT & 4k rule on myself) then there shouldn't be any danger of it happening. However that doesn't stop me crapping myself right now.

Actually, for what it's worth I was talking about ignition advance and whether the inlet change would have affected that - generally an engine will survive fine on low throttle/load with a bit too much ignition advance, but at WOT you run the risk of melting/breaking something. In terms of fuelling, you'd mentioned connecting your wideband lambda up to get a feel for what it was doing and making adjustments to the map where needed if it was significantly out - you won't likely damage anything from running lean at low revs/load, but excessively rich will borewash it whatever.

 

Like I said on the phone this morning though - if you think it's been running rich, then it would be a wise move to change the oil before going to Emerald to have the engine mapped, as fuel contaminated oil isn't going to be lubricating/protecting the engine as well as it otherwise would.

[Tom Fenton 1,542]

If you have a wideband lambda then get this connected ASAP- then you will get an idea for where it is rich and how much.

[DrSarty 90 1 Cars]

If you have a wideband lambda then get this connected ASAP- then you will get an idea for where it is rich and how much.

 

On idle, it's on 14.6/14.7, but it must be running rich, particularly when cold, as the plugs are getting sooted. A lot of the journies are regretably quite short, and I try and drive a while to get her to running temp i.e. warm, and I'm well aware that short trips are no good for any car.

 

I will reveal all from my Emerald trip, have no fear.

 

And PeterT just asked if I've installed the stage II regrind cam yet. Here's what I said:

 

Not yet I'm afraid my salsa making, budgie smuggling friend.

 

Current plan is remap on Monday 9th with new 46mm ITBs and inlet and one set of GTI6 injectors (all cleaned & certificated) and run the engine as is until after the EuroTrip.

 

Then, during the summer, the engine will come out for a refresh and the new cams will go in (much easier out of the car) and the final staged injector mod can be made. This will demonstrate a clear difference between the two set-ups.

 

It's about -6 here at the mo - snow & ice everywhere and I really don't fancy doing a cam belt change in the limited space in this weather.

 

When the engine comes out, I will have the head off again, clean EVERYTHING up, and pending dry assembly measurements, will have a safe skim or more likely a deck block, to bump compression up towards 12:1 providing safe clearances are there.

 

The engine bay will get another clean & tidy and then we'll go for final remap.

 

More than you asked for, but I hope it prompts a reaction.

 

One reaction MIGHT be, put the stage II on the exhaust and get something evil for the inlet, but I'm interested to hear what you say.

 

I forgot to mention that during the refresh she'll get a new clutch too.

Edited February 4, 2009 by DrSarty

[welshpug 1,657]

I think I've missed it, but what compression ratio is it running now?

[jimistdt 1]

I think I've missed it, but what compression ratio is it running now?

 

 

Its at the top of this page WP

[welshpug 1,657]

DOH!

[Anthony 1,003]

Decking the block requires stripping the whole bottom end back to a bare block Rich, which whilst not too difficult, is probably alot more work than you were envisaging and will mean addition costs that you might not have factored in - new rings and a quick deglaze of the bore for example.

 

To be honest, from what I can see of the specs for Petert's Stage 2 cam, I'd say that 11.6:1 is plenty of compression

[DrSarty 90 1 Cars]

To be honest, from what I can see of the specs for Petert's Stage 2 cam, I'd say that 11.6:1 is plenty of compression

 

Thank you. I am still amazed and have ultimate respect for those who get a 'feel' from understanding a set of cam specs.

 

Pete did a very good job of explaining cam lobes, timing, overlap, duration and lift etc, but seeing the whole picture, taking into account valve and port dimensions and compression ratios is very much black magic to me at the moment.

 

I'm happy to learn, but in the meantime you guys who understand engine dynamics are like gold-dust and I respect you a great deal.

 

FYI, Magic said almost word for word what Maxi did a few posts ago - and I'm sure it's not revolutionary - that high comp (N/A engine naturally) and clever cams is the way to get the best power from (our) engines. His 2.1 Mi hybrid that I described in my 'Slut Tales' thread typifies this, and is probably not far away from Maxi's engine and mine.

 

So in my ignorance I thought it might be possible to deck a block still loaded with pistons and crank. We live and learn. I might be tempted to try a Cu head gasket again though, although slightly thicker than last time but still thinner than a standard GTI6 gasket. This will achieve the same effect, and will be more reliable as I won't have to worry about liner protrusion to bite into the gasket like I had on the XU9 block.

 

Comments....

Edited February 4, 2009 by DrSarty

[taylorspug 7]

Is there not a Cometic MLS gasket that is thinner than the std '6 item? Would maybe be an alternative solution, and reuseable too.

Edited February 4, 2009 by taylorspug

[DrSarty 90 1 Cars]

Is there not a Cometic MLS gasket that is thinner than the std '6 item? Would maybe be an alternative solution, and reuseable too.

 

I'll look one up. Thanks Dan. Bit of a sour taste left after the last Cu gasket; but they MUST work. A lot of V8 American mobiles use them apparently.

 

Sound alternative though. Thanks again.