8v Vs 16v Power/torque Comparison

[Jonmurgie 2]

it's been proven you can get ~190 from an mi16 with a standard head, standard cams on TBs. Search for Mattsav's posts

Correct, I was getting 190+ (not going to spot on about 200!) with standard head/cams and TB's & ECU

[28CRAIG 2]

put it this way i raced a 1.9 8v when i was running my engine in, not going above 4k and there was very little between us until 80mph when i had no more revs. Plus mi is happy driving around at 2k without looking like you should have L plates on

[Jonmurgie 2]

Plus mi is happy driving around at 2k without looking like you should have L plates on

eh?! I think the Mi is a big pile of pooh under 4k... the 8v 'feels' much more drivable than the Mi below those revs...

[smckeown 1]

So Dave, Sean's 8v seems to be giving 76 ft lbs per litre is as you expected then? I think people are waiting with baited breath for you to pass your comments/thoughts on his results etc.

 

He's still unconscious after he fell of his chair and banged his head, as he saw I said I was very pleased with the results; even though it's currently delivering 9bhp less than he estimated It's still an animal

 

Edit: In a smart buy strange way, he's given his reply here. Shame he wont discuss why the power is trailing off somewhat compared with Craigb's same head and cam

 

Edit2: I have just realised he's also answered my question above by relaying the story of how a substancial number of hours on the rollers (compared to my 4 or 5) and with playing with trumpets is needed to extract all the numbers. Cheers Dave

Edited July 27, 2006 by smckeown

[pug_ham 244 3 Cars]

Having driven an Mi with a 1.9 gearbox I wouldn't recommend it to anyone, it just felt so flat in comparison to my 8v on a mixed ratio box. (equivilent to a 1.6 Gti box 1-3, exactly 1.9 4th & slightly longer fifth)

 

My 8v was RR'd when it was mapped at 140bhp but its got a decent flat torque curve & pulls very nicely through the gears for a basic spec engine. (standard 1.9 except balanced crank, L&B flywheel & Piper 270' cam on MP3.1).

 

If you've already got a good 8v (SBC is still quite low spec) spending half the money of a (properely) rebuilt Mi on your engine would see gains that will match it in terms of real world performance, 160bhp from an 8v will match an Mi16 imo with good selection of gear ratios.

 

Its your money but there is definately life to be had from the 8v yet before submitting to the 16v lure imo.

 

Graham.

[mos 1]

Having driven an Mi with a 1.9 gearbox I wouldn't recommend it to anyone, it just felt so flat in comparison to my 8v on a mixed ratio box. (equivilent to a 1.6 Gti box 1-3, exactly 1.9 4th & slightly longer fifth)

 

My 8v was RR'd when it was mapped at 140bhp but its got a decent flat torque curve & pulls very nicely through the gears for a basic spec engine. (standard 1.9 except balanced crank, L&B flywheel & Piper 270' cam on MP3.1).

 

If you've already got a good 8v (SBC is still quite low spec) spending half the money of a (properely) rebuilt Mi on your engine would see gains that will match it in terms of real world performance, 160bhp from an 8v will match an Mi16 imo with good selection of gear ratios.

 

Its your money but there is definately life to be had from the 8v yet before submitting to the 16v lure imo.

 

Graham.

 

 

i always thought skip brown engine were quite a high spec, to be honest i am steering towards the mi route but i interested to know what would you do to a 1.9 8v to realise the 160bhp?

 

i have a budget of upto about 2k left over from when i sold my souless audi tt afetr i cleared the finance

i have come full circle 205 gti to company cars, then expensive car back to a 205 and i can honestly say although the newer cars i have driven (and i driven quite a few because i used to be a fleet manager, fleet vehicle, demos etc) have been superior to the 205 in a number of ways such as build quality etc nothing has the same levell of character and fun as the 205, these include some of the newer pug gti's

i want to make the car truely quick but in a real world usable way as i am planning to use the car as my daily transport for a number of years to come

[smckeown 1]

i can honestly say although the newer cars i have driven (and i driven quite a few because i used to be a fleet manager, fleet vehicle, demos etc) have been superior to the 205 in a number of ways such as build quality etc nothing has the same levell of character and fun as the 205, these include some of the newer pug gti's

 

Have you driven a mini2 cooper s works 210 ? If I wanted a modern small fun car with lots of poke and character that's what i'd buy. I drove Gav's recently and it was great fun.

[mos 1]

Have you driven a mini2 cooper s works 210 ? If I wanted a modern small fun car with lots of poke and character that's what i'd buy. I drove Gav's recently and it was great fun.

 

i had an ordinary mini cooper s for a day once, i really quite liked it but the weather was awful rained heavily the whole time. problem was when moving off the car would wheel spin for fun the traction would kick in and you would end up kangarooing down the road! i actually turned it off and just wheelspinned off the lights, was much more effective and more fun and did remind me of a 205 gti in the wet with no lsd/atb.

 

on a quirky note the one other car i quite liked was the seat ibiza cupra diesel 160bhp!!! don't get we wrong was not the best car in the world but by modern hot hatch standards it felt a bit raw and the torque was great, the car did actually shift from standstill (unusual for most diesel) but like most diesels it really shifted was on the move. i drove a 206 180gti a few days later and although the handling better the car felt breathless in comparison unless you reved the tits off it but i did like the seats, in fact the seats in that were much better than those in my old tt!!!

driving things like the 206gti 180 have upto this week always convinced me 16v were breathless unless stretched, the clio 182 was a bit like that, felt like a 1.4 till it hit 4,500-5000rpm.

but the facts dont lie a standard mi16 seems to produce more torque consistantly through the rev range than a 8v does (i have done some searches and found a couple of graphs) and when pushed really goes where as the 8v does feel a stretched at around 5,000-6,000rpm

 

so i would imagine if both engines are modded like for like (if you see what i mean) then the mi16 would surely maintain its advantage over the 8v if not increase it as the figures quoted on daves (pumaracing)website imply

Edited July 28, 2006 by mos

[Craigb 2]

He's still unconscious after he fell of his chair and banged his head, as he saw I said I was very pleased with the results; even though it's currently delivering 9bhp less than he estimated It's still an animal

 

Edit: In a smart buy strange way, he's given his reply here. Shame he wont discuss why the power is trailing off somewhat compared with Craigb's same head and cam

 

Edit2: I have just realised he's also answered my question above by relaying the story of how a substancial number of hours on the rollers (compared to my 4 or 5) and with playing with trumpets is needed to extract all the numbers. Cheers Dave

 

Also possibly answered the difference in the lower revs Torque figures as seen on my plenum equipped engine

[petert 586]

please guys if i am wrong do tell me i am certainly no expert on this stuff

 

There's nothing wrong with the earlier heads. You don't have to have 43.5mm inlets. I've done the big valves into the small head thing, and you're right, it's expensive, as you have to fit bigger seats. Settle for a slighlty smaller valve and you don't have a problem. It's really not worth getting hung up on. The greatest increase in flow comes from the seat work.

 

Having said that however, this is my favourite. Remember it and you'll save a fortune.

 

"16V performance starts where 8V performance ends."

[Rob_the_Sparky 9]

I drive a tuned 8v and TBH think a 16v is better value for money. Stock Mi16 makes good power and can be further tuned should the desire strike. A tuned 8v is going to cost more to get the power a stock 16v will put out with no route for further tweaking.

 

From what I remember of the torque curves of stock 16 and 8 valve engines they are alomst identical upto the magic point at which the 16v takes off...

 

Rob

[mos 1]

was that an not so subtle message to go dow the 16v route petert?!

i it was it certainly working!

i have pretty much decided on the 16v route, is something i have not done before new challenge etc

i am pretty sure the 2ltr engines are the one to go for with there larger bore and better torque that from what i have read on here is delivered much lower in the rev range

but there are a few things i am not sure about

are the inlet/exhaust valves any bigger in the 2.0ltr mi16/s16 or even gti6 heads than the earlier 1.9mi16s or are they the same size

do the 2.0lts heads flow any better than 1.9lts (best i can tell is they are identical heads but i just want a definative answer) as this could potentially save cost on big valves/gas flowing potential or would the best bet be to have a big valve head/gas flow and hotter cams no matter what engine i start with

if at first i wanted to retain the 8v dizzy injection can this be made to work on either a gti6 or mi16 engine.

i will need a new carb inlet manifold but will the same 16v manifold work across the mi16s/s16 and gti6 engines or is it specific to each engine?

i currently have a magnex full system and manifold on my 8v i strongly suspect i will need a manifold but will this new manifold mate up with the rest of my magnex exhaust?

thanks

[petert 586]

The 2L Mi16/S16 engine is the "ants pants" in my opinion. Bigger bore, better rod/stroke ratio and all the internal goodies of the 1.9L, like oil squirters and full floating pistons. The only downsides are the squish height and the extra 18Kg, which is more than offset in the extra power you'll make. The heads are all but indentical to the 1.9L heads, in terms of valve train and flow. Inlet manifolds are interchangeable between 1.9L, 2L and GTi6. If you put carbs and a dizzy on one I'll never speak to you again.

Edited July 28, 2006 by petert

[smckeown 1]

Having said that however, this is my favourite. Remember it and you'll save a fortune.

 

"16V performance starts where 8V performance ends."

 

We've always known that type of thing, the problem has always been the oil surge/starvation issues with the 16vs. Now we have a cheap solution (ala PeterT) we can seriously consider the 16v for track work. If only I knew that 15 months ago Such is life

[Shevy 4]

We've always known that type of thing, the problem has always been the oil surge/starvation issues with the 16vs. Now we have a cheap solution (ala PeterT) we can seriously consider the 16v for track work. If only I knew that 15 months ago Such is life

 

 

Sean, do you mean the deeper sump and extended pickup mod as being the cheap solution or have I missed something else

[pug_ham 244 3 Cars]

i always thought skip brown engine were quite a high spec

Not really all that high spec imo, lightly gas flowed head, L&B bottom end, with their secret camshaft & peak power is developed at 6500rpm which isn't that much over standard & requires no fancy uprated bits in the bottom end at all. AFAIK they don't recommend revving much past 6k on this engine as all the work is done by then.

 

For the majority of use on the road then 16v is your best way to 160bhp+ but with this on carbs you should have more than that straight away.

 

I think you'd need a sleeve adpator for using your current system on the correct Mi manifold but without trying fitting them up to eachother I wouldn't like to guess what way. I thought the S16 head had a different exhaust manifold bolt spacing?

 

Graham.

[petert 586]

I thought the S16 head had a different exhaust manifold bolt spacing?

 

It does. Ten studs instead of nine. Ports are identical. I haven't tried it myself, but I can't see why the S16 exhaust manifold wouldn't be a good fit (in terms of alignment) to the 205 down pipe. I've heard people on here bag it, but I think it's a very clever casting.

[Ahl 4]

Now we have a cheap solution (ala PeterT) we can seriously consider the 16v for track work. If only I knew that 15 months ago Such is life

Theres been talk and discussion about the practical and easy 'solution' to mi16 oil surge for a long time, just most people, internet mechanics of course, were too busy jumping on the "Theres no cure!" bandwagon to notice.

[Dino 3]

Theres been talk and discussion about the practical and easy 'solution' to mi16 oil surge for a long time, just most people, internet mechanics of course, were too busy jumping on the "Theres no cure!" bandwagon to notice.

 

I've yet to have a serious issue with oil surge unless I've running low on oil. It does seem that some Mi16s suffer badly from it and others dont.........I do have a baffled sump which probably helps a tiny bit I suppose.

 

Perhaps I'm not cornering hard enough eh?

[Ahl 4]

Perhaps I'm not cornering hard enough eh?

That must be it Dino.

 

I corner really hard (in my head) and im always getting imaginary oil surge.

[smckeown 1]

Theres been talk and discussion about the practical and easy 'solution' to mi16 oil surge for a long time, just most people, internet mechanics of course, were too busy jumping on the "Theres no cure!" bandwagon to notice.

 

I've been on the forum about 4 years and didnt come across PeterT's solution until he posted it recently. I've seen the additional drain hole in the head, but never seen proof it works.

Edited July 28, 2006 by smckeown

[easypug 0]

I've been on the forum about 4 years and didnt come across PeterT's solution until he posted it recently. I've seen the additional drain hole in the head, but never seen proof it works.

 

On that note, i brought an engine that had the additional drain in the head. Whether it was being used at the time it span a shell on No.3 i don't know. But if it was then it proves it don't work all that great at all. Like Jon says "dry sumping if the only real way" of preventing this 100%

Edited July 28, 2006 by easypug

[mos 1]

petert

 

i am not being thick honest!

but did you mean that dizzy and carbs would work well or that this is a bad idea and i should use mapped ignition

also i take it that all though the 16v inlet manifold is interchangable with all the various 16v engines that my current 8v manifold with have to be replaced

 

the sleeve thats been mentioned for the exhaust what is this and where would i get one

 

 

everyone,

 

i have been having a hunt around this afternoon for an engine but i cant find any mi16,s16 or gti6 engine anywhere in the manchester area.

anyone any idea where i could source one and what sort of money i am looking at?

Edited July 28, 2006 by mos

[veloce200 3]

the good old 8v vs 16v banter ! Someone mentioned throttle response and this is it. The thing I find about most 16v engines it unless you rev them they "feel" flat, so you end up going well over the limit. The thing about the 8v with 1.9 g/box is even in 5th gear at 50mph it still feels responsive and pulls well. So you short shift but still feel like you are flying along.

 

I seem to remember someone posting stats on Xu9j2 8v SRi engine having MORE torque than 16v around 1500-3500. This has TINY ports so yes Peter's point s about gas speed bear true. Maybe this is why the MI flows so poorly at low lifts - I saw one at QEP the other day and ports are huge ! (std head).

[Sandy 191]

Mi inlet ports are huge, there's a better 16v XU head with some light porting, but the 205 world doesn't seem to have woken up to it yet

 

I've said it before, but none of the competition Mi16 engines people I know well are running, have suffered oil surge. They all have solid lifters, baffled sumps and decent rod bolts. I mention the rod bolts because I believe spun bearings on these are probably down to the cap lifting, rather than oil supply.