Saxo Engine/Performance If you're interested in tuning Saxo engines, or if you need to know something which is engine related... this is the place for you. |
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11th December 2011, 20:50
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#41
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Established Member
Join Date: Mar 2006
Location: Farnham Surrey
Posts: 1,542
Car(s): AX GT 16v turbo 6 speed with NOS
205 gti6
E 320
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my 1st engine had 1mm low comp pistons, a 2mm decomp plate and a 1.4mm gasket
couldnt really drive it off boost as it was on full boost by 2k but would of made alot more power with a higher CR
the only reason i have kept my new one under 9:1 is i am running nitrous aswell as boost
ill be useing the decomp plate as the HG with the 16v head
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12th December 2011, 17:17
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#42
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Saxperience Post Whore
Join Date: Feb 2006
Location: dudley United Kingdom (England)
Posts: 6,790
Car(s): 106 gti/ SEAT LCR
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Quote:
Originally Posted by blackie_2k5
what is the CR your running danny, i wouldnt say mine was massivley low, drives fine on and off boost so its all worked out well 
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Runs well yes, but could it be/feel better? The only way you can find out is if you do and then you will know the difference.
My compression ratio is 9.3-1 but I want to make it 9.5-1 with my new bottom end.
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Boost pressure is underrated
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13th December 2011, 20:36
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#43
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Saxperience Hardcore!
Join Date: Oct 2008
Location: Birtley
Posts: 22,253
Car(s): VTR Turbo, 106 xsi track slag, Transit recovery, B
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im sure with a slightly higher CR it "could" feel/go a little better, but is that at risk of how long itll last...
it goes well enough and made fair power so im happy for now, need forged pistons and rods
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Originally Posted by Stissy
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13th December 2011, 20:45
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#44
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Frequent Poster
Join Date: Dec 2011
Location: Thorne+Grimsby
Posts: 717
Car(s): S2GTi / Megane cc
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Quote:
Originally Posted by blackie_2k5
im sure with a slightly higher CR it "could" feel/go a little better, but is that at risk of how long itll last...
it goes well enough and made fair power so im happy for now, need forged pistons and rods 
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Your car is a real inspiration mate. Its one of the cars that's convincing me to sell the turbo xsara when I've finished it and get some boost into the saxo. Trouble is I don't know whether to stick with the 8 valve or go 16.
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13th December 2011, 20:57
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#45
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Saxperience Hardcore!
Join Date: Oct 2008
Location: Birtley
Posts: 22,253
Car(s): VTR Turbo, 106 xsi track slag, Transit recovery, B
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thanks mate its nice to hear  , i like to think it has helped a few ppl tbh... i never had the biggest budget but that never stopped me,
so if nothing else its nice to think it may have shown some ppl that money isnt alway the be all and end all
and its made good power
EDIT- also, if it were me allover again, id be a sheep and go 16v, just becuase i want more now  but mak no mistakes mate, the 8v its seriously quick atm, and youd really be surprised what cars it puts to shame... i love the fact its 8v which is why i want to stay with it and forge it, no greater feeling then telling ppl its a 1.6 8v
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Last edited by blackie_2k5; 13th December 2011 at 20:59.
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13th December 2011, 21:02
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#46
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Frequent Poster
Join Date: Dec 2011
Location: Thorne+Grimsby
Posts: 717
Car(s): S2GTi / Megane cc
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Exactly, I was really impressed with your dyno results and your spec. I've got a vtr lump, loom and ecu that I'm thinking about dropping in the desire and taking to a similar spec to yours.
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13th December 2011, 21:08
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#47
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Saxperience Hardcore!
Join Date: Oct 2008
Location: Birtley
Posts: 22,253
Car(s): VTR Turbo, 106 xsi track slag, Transit recovery, B
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go for it mate, it WILL make you happy lol,
dyno results should always be taken with a pinch of salt tbh, as most are quite unrealistic unfortunatley, and ppl will always question them
the dyno i used is known to be accurate...
but still had i not seen about 60-70 cars over then 2 different dyno days, all with varying driven wheels and specs, id have probs questioned mine tbf, but all the figure matched the specs and expected outputs.... there were about 5 cars with problems the dyno highlighted (including mine in the first day) which didnt make expected, but you could even tell by smells and smokes of these cars they had issues
also had a couple the were dyno'd at another dyno's, days or weeks before that were only a few bhp diff then on the days, so im pretty confident theyre fair...if anything the dyno reads sligthly under in some cases
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Quote:
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Last edited by blackie_2k5; 13th December 2011 at 21:13.
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13th December 2011, 21:36
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#48
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Saxperience Post Whore
Join Date: Feb 2006
Location: dudley United Kingdom (England)
Posts: 6,790
Car(s): 106 gti/ SEAT LCR
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What did yours make atw blackie?
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Boost pressure is underrated
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13th December 2011, 21:41
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#49
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Frequent Poster
Join Date: Dec 2011
Location: Thorne+Grimsby
Posts: 717
Car(s): S2GTi / Megane cc
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Quote:
Originally Posted by dannygti
What did yours make atw blackie?
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I've started reading through your progress thread today Danny, its going to take me a bloody week to get through that!
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14th December 2011, 09:25
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#50
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Saxperience Hardcore!
Join Date: Oct 2008
Location: Birtley
Posts: 22,253
Car(s): VTR Turbo, 106 xsi track slag, Transit recovery, B
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Think it was around 185atws Danny, I'll dig the graph out later, packs a punch though lol
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Originally Posted by Stissy
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Originally Posted by Giraffe
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14th December 2011, 20:44
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#51
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Saxperience Post Whore
Join Date: Feb 2006
Location: dudley United Kingdom (England)
Posts: 6,790
Car(s): 106 gti/ SEAT LCR
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Quote:
Originally Posted by blackie_2k5
Think it was around 185atws Danny, I'll dig the graph out later, packs a punch though lol
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You don't need to tell me that lol I know how fast they are haha
I've only used 10% transmission losses :|
it's interesting to see different places use different losses.
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15th December 2011, 08:56
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#52
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Saxperience Hardcore!
Join Date: Oct 2008
Location: Birtley
Posts: 22,253
Car(s): VTR Turbo, 106 xsi track slag, Transit recovery, B
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Yeah, mine was about the same as adz's supercharged S at the wheels but his made about 2bhp more ATF,
What were you fly figures?
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Originally Posted by Stissy
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15th December 2011, 16:38
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#53
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Saxperience Post Whore
Join Date: Feb 2006
Location: dudley United Kingdom (England)
Posts: 6,790
Car(s): 106 gti/ SEAT LCR
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10% on 250 so 275@flywheel. If I used your lads % it would give me around 290@flywheel
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15th December 2011, 19:08
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#54
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Saxperience Hardcore!
Join Date: Oct 2008
Location: Birtley
Posts: 22,253
Car(s): VTR Turbo, 106 xsi track slag, Transit recovery, B
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Yeah I think mines somewhere in the region of 15%, I've not worked it out tbh, I might do later if I get time, does anyone know the correct transmission loss on the Saxo set up is?
The dunno I use belongs to an Evo specialist, so may be set up for tranny loss on those, but may also be set up as a general loss, as most run off about 10-20% don't they
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Quote:
Originally Posted by Stissy
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Originally Posted by Giraffe
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15th December 2011, 19:15
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#55
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Saxperience Post Whore
Join Date: Feb 2006
Location: dudley United Kingdom (England)
Posts: 6,790
Car(s): 106 gti/ SEAT LCR
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Yours works out to 18%. my car would be 297@flywheel using that figure lol
There's no set % for losses. The only way to get true engine power is engine dyno. Flywheel power Is a guess really and it depends on who's rollers you use TI what losses they will give you. Lots of things can effect power at flywheel so that's why you should take those figures and forget them.
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15th December 2011, 20:59
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#56
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Saxperience Hardcore!
Join Date: Oct 2008
Location: Birtley
Posts: 22,253
Car(s): VTR Turbo, 106 xsi track slag, Transit recovery, B
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yeah i know mate, i just thought the likes of sandy may know a good estimate for tranny loss through the saxo/106 set up, being as he does alot of engine dyno work
pity as it'd be handy to have tbh...i know itll never always be the same, but a good figure to work off may help
im just happy with how it goes tbh, i never really had the intention of making big figures, i just wanted it to make about 200bhp for A.. having that magic number.. and B from reading up it what most ppl deemed a very quick car for a saxo/106
so even on 10% losses ive tipped it  which is pretty cool tbh
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Quote:
Originally Posted by Stissy
EDIT: i give up on you.
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Quote:
Originally Posted by Giraffe
FUCK YES. I won on the internet.
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15th December 2011, 21:09
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#57
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Saxperience Post Whore
Join Date: Feb 2006
Location: dudley United Kingdom (England)
Posts: 6,790
Car(s): 106 gti/ SEAT LCR
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Definately good going mate, I'm not trying to knock anyone's work or cars for that matter I just find it wierd how there can be such a large difference in losses.
When my car was making 180'ish atw it was rapid and no normal stuff on the road can keep up.
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Boost pressure is underrated
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15th December 2011, 22:16
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#58
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Saxperience Hardcore!
Join Date: Oct 2008
Location: Birtley
Posts: 22,253
Car(s): VTR Turbo, 106 xsi track slag, Transit recovery, B
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oh i know, mate, its all about the percentages though really, the more you go the bigger the diff is..
thats why alot of supposedly high figure'd car's get shown up by cars that were allegedly running alot less. and why ppl should only take numbers with a pinch of salt
dyno is better as a health check then anything else
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Originally Posted by Stissy
EDIT: i give up on you.
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Originally Posted by Giraffe
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16th December 2011, 07:25
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#59
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Regular Poster
Join Date: Jan 2010
Location: Cornwall
Posts: 349
Car(s): 106 XSi
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The only thing you need to know about rolling roads, is that the figures are estimated. Transmission loss is a real misnomer, the tyres account for a large proportion of the loss. The actual gearbox and final drive loss, with a healthy box, is about 8-10% of flywheel power (going by the engines we've run on hub dynos after the engine dyno); the rest is the tyres and that can vary hugely (twin rollers have much greater tyre loss than single rollers), that's the simplest way of looking at it.
To look deeper, you need to consider how the wheels figures are obtained. Traditionally (older analogue rolling roads), the rollers are braked by a large eddy current retarder, which leans on a load cell. The load cell reading is literally torque; to make matters worse, the torque is mulitplied by gearing and tyre size. Older rolling roads simply work on an average gearing to convert to torque at the wheels and typical rpm to get power at the wheels; all of that averaging and multiplication means that "wheels power" is not a literal figure, it's calculated as an estimate and accuracy varies with gearing and tyre size, significantly! The coast down after was dreamt up to try and estimate the transmission loss; but older systems basically measure the free running inertia, not the actual power absorbtion of the transmission (that's a major point) and of course the situation under full power is quite different.
Over the years, computers and improving software allowed the rollin road manufacturers to get better as estimating, taking more factors into account and more data to improve the averaging of the losses etc. But the principals are still the same, you have a load cell on the brake and try to correct it by better calcuation of the gearing reduction, then estimate the transmission/tyre losses. If you're doing the same cars all the time, in similar condition, you can achieve good repeatability, but beyond that, there are still several ways that the figures can be corrupted.
Different rolling road systems calculate the wheels and loss figures in different ways, so you can't compare very well between systems. For example, MAHA LPS3000s, generate relatively low wheels figures and high losses, that don't compare with the lower loss and higher wheels figures from Superflow and TAT are somewhere in between, also twin rollers work differently to single rollers.
All systems struggle to cope with the way tyres behave at different speeds and generally, if you run a car at very high roller speed (ie over 120mph), the system will usually over correct the tyre losses and the figures get inflated; conversely at low roller speed (under 80 mph), tyre losses get under compensated usually. Tyre distortion reduces at high speeds as the carcass expands through rotational inertia and recedes the contact patch, but the rolling road will continue to slope the tyre drag upwards, according to the pattern of the lower part of the curve. How the car is strapped can also affect that scenario.
If you want to get precise figures, a properly calibrated and corrected engine dyno, is the only way.
Last edited by Sandy309; 16th December 2011 at 07:33.
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16th December 2011, 19:13
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#60
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Saxperience Post Whore
Join Date: Feb 2008
Location: wirral
Posts: 6,348
Car(s): Icelandic vtr turbo
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cheers sandy that was a great read, opened my eyes to RR's and used and how the powers worked out.
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