Engine Tuning - The Sensible Approach?

[v8s4me]

There’s a conversation going on FB at the moment about engine tuning, the 2.9 in this case. There’s all the usual about big valve heads and fast road cams but I take a different line. The photo sums up my opinion that the best route is to spend modestly to improve the everyday driveability of the car. That means balancing the spend against the potential return in terms of living with the car. In other words, look at improving the “characteristics” of the engine rather than chase absolute numbers which are arguably meaningless.



Discuss...

[mk1fan]

Mike will be please another has been asimilated into FB He may splurge on some Tesco Value Lager

I agree. Decide what and how you want the engine to 'drive' and build accordingly. No point having a stump puller at low revs on the track and no point having a screaming race engine on the road.

[v8s4me]

mk1fan said:

Mike will be please another has been asimilated into FB ....

No he won't! He knows my views on FB and I'm a long way from being "assimilated" - Two s's, you're on PH now so correct grammar and spelling WILL be observed. You can keep that sloppy predictive text crap for FB

[mk1fan]

Denile, it's the finial stage ..

[phillpot]

Got myself a beer, lets catch up with what's going on on PH (shouldn't take long )

[v8s4me]

Not that much happening of FB either at the moment - unless you want to know why it's unwise to take the rad cap off a hot system. Or want to know what pressure might be in the system when you have a 15psi rad cap

[frontfloater]

I'm not sure what responses the original post is seeking. But in case it's any help, this is what you get from Specialised Engines in their three categories of 2.9 Cologne rebuilds :

Standard rebuild:

All parts immersed in acid ‘bath’, then chemically ‘hot’ washed and cleaned.
Cylinder Head : Completely reconditioned with new valve springs, stem seals, valves, valve guides and head surface ground as necessary. All valve seats re-cut or new inserts fitted as required.
Cylinder Block : Rebored and cross hatch honed. All new core plugs fitted. New matched set of pistons. Mains checked for alignment and ovality. Surface ground where necessary.
Crankshaft : Reground and polished. All new mains and big end bearings, seals and gaskets (Genuine Ford parts)
Con Rods : Checked for alignment and ovality in big end housing.
Camshaft : Reprofiled with new or resized cam followers.
Oil Pump : Fully reconditioned or replaced.

Stage 1 : As above, plus :

Cylinder Head : Modified and fully gas flowed with matched set of valve springs.
Cylinder Block : Rebored to 0.030". Each bore cross hatch honed to exact size of each individual piston, each ring gapped and graded to each individual piston and bore.
Crankshaft : Reground to bottom limits available, with matched set of mains and big end shells.
Con Rods : Crack tested and checked for alignment. Checked for ovality in big end housing. Fully balanced and lightened.
Camshaft : New specially selected. New cam followers.
Oil Pump : New latest type.

Stage 2 : As above Standard + Stage 1 , plus :

Big valve heads, inlet valve size 44.5mm, exhaust valve size 38mm. Cutting and throating of valve seat areas to accommodate bigger valves. Further matching of ports and matched inlet manifold.
Camshaft : ‘Fast Road’ for gains in BHP or ‘blueprinted’ cam for maximum torque (for use in towing, for example). New solid lifters used with modified camshaft.
Timing Gears : Fitted with a modified dowel to give exact valve timing.

I went for the full stage 2 conversion, plus the optional extra of a full engine balance :

"All our modified engines have a ‘half balance’, i.e. the balancing of pistons and con rods. (See specifications). The ‘full balance’ also includes crankshaft, front pulley assembly, flywheel and new clutch pressure plate."

My engine had 34000 miles at the time, and was already fitted with a factory free-flow stainless exhaust plus stainless manifolds and downpipes from Richard Thorpe. At 49000 miles, just before I sold it, the dyno figures were 193.4 BHP and 199.6 torque (factory figures when new were 168 / 170). It went to 6200 revs on the rolling road (loud!).

My engine had overheated & seized, so I had to have a rebuild anyway. The standard spec would have cost about £2000, and the full stage 2 was £3600 - I regarded that as a no-brainer. In return for that extra spend, I got +15% on factory new BHP and +17.5% on torque.

BOB

[v8s4me]

Thanks Bob - it's an open topic for discussion. Have you got a photo of the dyno print out so we can see how the curves look? It would be interesting to see this against a standard engine in good condition if someone has one.

[frontfloater]

Yes, this is the dyno print-out from a couple of years ago. The BHP line is exactly what you would want to see on a modified engine - an almost straight diagonal line, without the typical "kick" half-way along where the engine stops being sluggish and "comes onto the cam". The torque line is pretty good too, fairly flat most of the way along.

The downside was an engine which averaged about 20 MPG - typically 25 on a long motorway run, 17-18 around town or having fun on country roads. That didn't matter when petrol was £3 a gallon at the time of the rebuild, but was one of my several reasons for selling this year.



BOB

[v8s4me]

Thanks Bob - yes that looks impressive and as I would have expected - and good value for money. I wonder if using the standard profile "blue printed" cam would have given you a flatter torque curve and avoided the torque drop off at 4250rpm? I'm guessing though that you were changing up at this point so probably didn't notice anything. Did you ever get a chance to drive above 4250rpm in top for a sustained period to see if the torque drop off was off set by the rising power?

These are the results I got following a Powers rebuild on my V8S (pretty much the 4th line on my table above but + a Mark Adams chip).



So let's move the debate on a stage; given your modified V6 produced broadly similar power and torque numbers (but different characteristics) and similar mpg, is it worth modifying a V6 or just spend a bit more and buy a well sorted V8S?

Because we can't measure the enjoyment/satisfaction in modifying can we set these considerations aside for the purposes of this debate?

[spitfire4v8]

Trouble is a nice sorted v8s is over 20k now whereas a nice v6 can still be had for what 10-12k ? Modifying the V6 is better value unless you particularly like the V8 looks and sounds ..

I remember back in the day Podie had a dastek unichip on his V6S and got good results / improvements for not much money. These days you'd probably go straight to a full aftermarket ecu but in terms of value for money the piggyback dastek was very good. Not sure if you can still get them though.

[v8s4me]

You should be able to get a well sorted V8S for under £20k (mine was!). To make modifying a V6 worthwhile you need to start with good one in the first place. So that's say £10k as a starting point, add another £4k as per Bob's post above and you're already on £14k and that's assuming you can do a lot of the work your self (I'm guessing Bob's quoted prices were just for the engine work and did not include taking the engine out/refitting and all the other little jobs that need doing along the way - Bob, correct if wrong please). OK so a modified V6 may still be a couple of grand less than a good V8S but what's the trade off?

Can I bring the discussion back to how drivable a modified car might be? Chasing numbers can be a goal in itself and I'm happy to concede that some owners are quite happy to trade off day to day driveability for headline numbers and if that's how an owner want's to spend his money then that's fine.

Can we agree though that anything gained over 3500rpm on the road in normal driving conditions is academic? If the gains resulting from modifying a V6 are predominantly above 3500rpm is it really worthwhile? Even if there is no negative impact on performance up to 3500rpm compared to a healthy standard engine?

[spitfire4v8]

v8s4me said:

You should be able to get a well sorted V8S for under £20k (mine was!). To make modifying a V6 worthwhile you need to start with good one in the first place. So that's say £10k as a starting point, add another £4k as per Bob's post above and you're already on £14k and that's assuming you can do a lot of the work your self (I'm guessing Bob's quoted prices were just for the engine work and did not include taking the engine out/refitting and all the other little jobs that need doing along the way - Bob, correct if wrong please). OK so a modified V6 may still be a couple of grand less than a good V8S but what's the trade off?

Can I bring the discussion back to how drivable a modified car might be? Chasing numbers can be a goal in itself and I'm happy to concede that some owners are quite happy to trade off day to day driveability for headline numbers and if that's how an owner want's to spend his money then that's fine.

Can we agree though that anything gained over 3500rpm on the road in normal driving conditions is academic? If the gains resulting from modifying a V6 are predominantly above 3500rpm is it really worthwhile? Even if there is no negative impact on performance up to 3500rpm compared to a healthy standard engine?

There's only one v8s for sale on PH and ebay and its 29grand .. admitted that's not typical, but if you want a nice v8s nowadays (rather than rubbish masquerading as a nice car) you're going to have to pay.
On the other points ..

As long as you don't go wild on cams then drivability won't be compromised, the cam more than anything else in an engine dictates that drivability / performance trade off. No idea what a blueprinted cam is ??

I make my living tuning engines so I might be a bit biased here, but see a lot of cars .. and no I don't agree that anything over 3500 rpm is academic. The sorts of people who never go above 3500rpm aren't the sort of people who would be considering engine mods in the first place.
Only the person paying the bill can decide if it's worthwhile modifying the engine, but if they're considering it then they are already a performance orientated kind of person so are more likely to find it value for money than somebody who just likes the looks / sounds of our cars and doesn't regularly explore the performance side.
People who say they've modified an engine and didn't like the results either didn't have a clear goal in the first place, or got greedy with the cam, or were misled and just had a really bad set of modifications done by someone who didn't really know what they're doing ..
If you do things properly with a clear goal then you may well find you end up with not only a faster car but one which uses less fuel in the process (by improving the part throttle efficiency) .. I can't ever think that anybody has asked me to reverse their modifications because they didn't like it the end result.

Edited by spitfire4v8 on Thursday 17th November 13:27

[keynsham]

Ever thought of supercharging? I supercharged an MG midget once and it was amazing the power difference. They work right through the rev range as they are pulley driven, you can adjust how much boost you get by pulley size to speed or slow the supercharger speed, it's a bolt on kit with no other mods necessary and is easily reversible. 30% increase is normal for supercharging and no lag like a turbo!

[v8s4me]

Tried and tested kits available for both V6 & V8 and it terms of BHP/£ very cost effective.
Power and torque gains throughout the rev range but you'd need to be sure you had a strong engine to start with

[NeilS3]

Haven't been on here for a while so hi folks.

With a tweaked V6 only producing around 190 bhp from a standard 160 - 170bhp engine the power gain is a tad small for the £3 - 4k out your pocket, is it worth the hassle and expense? I'm tempted to just do some headwork on my S3 looks like the most cost effective bhp/torque gain.

Regards
Neil

[frontfloater]

"(I'm guessing Bob's quoted prices were just for the engine work and did not include taking the engine out/refitting and all the other little jobs that need doing along the way - Bob, correct if wrong please). "

No, £3600 was for the complete job with all those items I listed, plus a new heavy duty clutch. The only extra fee was about £150 for a mandatory short 1st service at approx 1000 miles, required to get a warranty on the rebuild. Those were 2005 prices, but the company's website "latest ad" (undated) doesn't seem to show any increase.

In reply to your question about sustained driving above 4250 RPM, that equates to 100 MPH in 5th on a standard geared V6. So the answer is only once, for about an hour on an exceptionally deserted M1 after midnight ; and the concentration needed to do that meant I was not thinking at all about torque versus BHP.

"is it worth modifying a V6 or just spend a bit more and buy a well sorted V8S?"

That was answered for me on a quite different basis, the only time I tried driving a V8S. I found the clutch so heavy, and the gearchange so poor (Rover SD-1 if I recall correctly), that I abandoned any thoughts of trading up. So if I was considering another S in the future, I would certainly split my money in the same way again, ie buy as low a mileage V6 as possible and get a professional to modify it. On a separate topic, I also think the big pointless hump in the V8 bonnet is unattractive and spoils the S's low sleek lines, but of course this is personal preference and I realise I may be risking the wrath of others ... !

By the way, my modified car is for sale on Autotrader by the elderly chap who bought it 2 months ago, in case anyone fancies it. Apparently his missus couldn't see over the dashboard and had problems getting in & out, so he put it back on sale almost immediately after buying it. I'll certainly be able to answer any questions better than he could, so feel free to e-mail me if interested (edited out ; car no longer available). Unfortunately, he's in the far north of Scotland, but it's a cracking car and well worth the trip.

https://www.autotrader.co.uk/car-details/202209139...

BOB

Edited by frontfloater on Friday 18th November 10:28

Edited by frontfloater on Wednesday 11th October 13:29

[v8s4me]

frontfloater said:

"(I'm guessing Bob's quoted prices were just for the engine work and did not include taking the engine out/refitting and all the other little jobs that need doing along the way - Bob, correct if wrong please). "

No, £3600 was for the complete job with all those items I listed, plus a new heavy duty clutch. The only extra fee was about £150 for a mandatory short 1st service at approx 1000 miles, required to get a warranty on the rebuild. Those were 2005 prices, but the company's website "latest ad" (undated) doesn't seem to show any increase.
BOB

Bob - thanks for clarifying. That sounds like pretty good value for money then.

frontfloater said:

......In reply to your question about sustained driving above 4250 RPM, that equates to 100 MPH in 5th on a standard geared V6. So the answer is only once, for about an hour on an exceptionally deserted M1
BOB

One of my posts seems to have vanished so here is the comparision table again..



This table compared the figures from your standard car (which also seems to have disappeared) with your modified results. My observation in the earlier post was that aside from a very modest increase in torque up to 2000rpm your main gain was from 3500rpm to 4500rpm. IIRC around 3500rpm is around 80/85mph in a V6 so although the work was very good value for money in financial terms I still question how the modifications improved day to day driveability. Very rarely by the sound of it. I'm very happy to acknowledge that you got a lot of work done for a very reasonable financial outlay but I question what practical improvement there was; I'm back to the day to day driveability debate now.

frontfloater said:

......"is it worth modifying a V6 or just spend a bit more and buy a well sorted V8S?"

That was answered for me on a quite different basis, the only time I tried driving a V8S. I found the clutch so heavy, and the gearchange so poor (Rover SD-1 if I recall correctly), that I abandoned any thoughts of trading up.

The Ford 'box is smoother and the Ford clutch is lighter for sure. But the Rover gear shift is very sensitive to the oil used in the 'box. Changing to something like Difflock transforms the gear shift. The ball socket on the end of the gear lever get clagged up with ste and makes the shift sticky and heavy. Cleaning this joint and fitting new bushes to the remote casing makes a huge difference. Whilst the Rover shift may never be as slick as the Ford it should still be smooth, positive and easy to use. The clutch on my V8S wasn't much heavier than my daily driver so I think the car you drove was a poor example.

frontfloater said:

.....By the way, my modified car is for sale on Autotrader by the elderly chap who bought it 2 months ago, in case anyone fancies it.
https://www.autotrader.co.uk/car-details/202209139...
BOB

Good luck with the sale! It looks like a cracking car for the money. (Maybe the guy finds the HD clutch too heavy?)

Edited by v8s4me on Friday 18th November 10:01

Edited by v8s4me on Friday 18th November 10:03

[frontfloater]

"Maybe the guy finds the HD clutch too heavy?"

No, it was (and should still be) an easy pedal. The V8 I tried may well have needed a service ; when I first tried the clutch with the car at rest, I thought I had put my foot on the brake pedal by mistake. I reckon after about a dozen clutch operations my left leg would have run out of strength to depress it ; and that was when I was only around 40.

BOB

[keynsham]

I never really understand why TVR clutches are so heavy. I have a 350i wedge with a standard Rover SD1 Vitesse engine gearbox and clutch but TVR have managed to make the clutch really heavy. I am sure it wouldn't have been acceptable like that on the Rover! It is only a case of mechanical advantage on the pedal lever so there must be another reason for them to be so heavy?