1.9l Vrs 2.0l Power

[petert 554]

It's always dangerous to compare different dynos, especially those in different hemispheres! However, given the spec. of Mattsav's engine from this thread, http://forum.205gtidrivers.com/index.php?showtopic=48816 is very similar to my 2.0L engine, I thought I'd give it a go. So I collated the power at the wheels from each and this is the result. I know mine is tailing off up the top end due to the conservative ignition timing, but an otherwise interesting result.

[Dom9 2]

Pete, got to be honest... Probably a bit harsh putting that up as a direct comp. even with your caveat in the first line!

[petert 554]

you're probably right, the only thing really in common is the oil pump and the 48mm TB's. Although the cam timing is almost identical.

Edited April 16, 2007 by petert

[VisaGTi16v 1]

Why does Matts have such a sudden flat spot from 6-6.5k or has this been explained in some other thread?

[Sandy 189]

Add the GTi6 I did recently?

It had 45mm TB's, light headwork (yours truly, standard valves), standard exhaust manifold with decat, catcam 4903110's, 10.8:1 CR.

 

BHP at the wheels @SRD:

2000 39

3000 59

4000 93

4500 107

5000 112

5500 147

6000 152

6500 168

7000 175

 

Peakier than I was happy with, but there was no scope to play with the cam timing (had to grind for enough clearance for spec timing) and it would probably benefit from hgiher CR, but the budget didn't allow for pistons!

[petert 554]

Here it is, although I think we going to get shot down in flames shortly! I guessed the 3500 figure.

[Sandy 189]

Cheers Peter, it did feel a bit peaky on the road, but it was lugging a 306 along and the Trio's my benchmark lately! When we were mapping it, Mark (Shillaber) and I were thinking it was a bit average up to 5500, we thought it was rolling over the top at 6000, then 6500 and 7000 came as a complete surprise! At 7500 it dropped back alot, possibly pumping the lifters. Overall inlet length is approx 370mm from the valve.

[petert 554]

Mine are 345mm, trumpet mouth to valve.

[DrSarty 90 1 Cars]

Pete, as you know I respect you as I am your customer.

 

However, I also respect Sandy and Mattsav for their experience. But what is your underlying point here? Is it displacement?

 

Your thread says 1.9 versus 2.0L power, but are you referring to like-for-like components but with different capacities, OR are you referring to tuning abilities? I think the former.

 

The Sarty Grenade has been launched.

[petert 554]

I thought the thread would point out how easy it is to get a nice broad torque curve with the iron block. I would have thought the shape of the power curves would be similar given the cam timing of the engines are basically all the same, which they are. So what you should be seeing is the improvement from capacity increase and possibly unshrouding of the inlet valves from using an 86mm bore, rather than 83mm.

 

If anything, I'm probably shooting myself in foot if you compare the maximum output of Matt's engine and mine. It's important to remember that it's a pointless exercise trying to compare power outputs between different dynos, even the same on different days. You could apply a tolerance of +/- 10% to each set of figures. What is important is the shape of the power curves, and the resultant torque curves that would be produced.

[DrSarty 90 1 Cars]

Thanks Pete, that's kinda what I hope you'd say. My RR torque curve was as linear and pleasing as yours. I have learnt that horse power in itself is meaningless. Tractability and manner of delivery is what dictates the characteristics (and the intended application) of the engine.

 

This is why I am planning to shift my treated head onto a bored out (87mm) iron block to gain the added torque but maintain the smooth delivery.

 

I wonder what Black Mi16 and our friend Puma has to say about this. Watch your foot Pete

 

Rich

[B1ack_Mi16 67]

I'm really not going to say anything, I haven't got too much clue about tuning engines yet, I'm more into how to modify engineblocks to get more displacement

 

However I will have the 2.3 litre rollingroaded in hopefully 1-2 weeks time, and it will be very interesting to see how that performs. As it's now it feels kinda peaky as it goes insane above 4000rpm.

[Mattsav 1]

My engine has always lacked mid range for some reason. The 48mm TB's probably dont help.

 

Plus mine is a completely std engine with cams & TB's, not even a 3 angle seat or valve backut. Std compression & squish

 

Here's Trevs 2.0 S16 graph

Revla's 2.0 Mi16

 

This is a std engine with 3 angle valve seats, cams and TB's. The pistons are still 1mm down the bore.

[petert 554]

I've added Revla's by dividing his flywheel HP by 1.2 to get it roughly into wheel HP. Rough I know, but a trend is certainly developing. For a more direct comparison, I've added an Mi16 I did recently, which has a Stage I cam, decked block and 10.8:1. It was done on the same Dyno Dynamics dyno, same gear, etc.

[VisaGTi16v 1]

Why do you think that "stage 1 mi16" only made 120 at the wheels? thats a fair bit down on standard regardless who's formula you use to calculate estimate flywheel power?

[Batfink 201]

my standard mi16 with 45mm tb's made 146bhp at the wheels and seems to be about right for just bolting on. Kt's and Base-1's with similar mods made as near as dammit the same power.

 

Kt's is a lot better now with an inlet cam - would be good to get that on the graph too

[petert 554]

Why do you think that "stage 1 mi16" only made 120 at the wheels? thats a fair bit down on standard regardless who's formula you use to calculate estimate flywheel power?

 

No, that was spot on the money and consistent with other results on the same dyno. A healthy standard 205 makes approx. 70kW (94hp) at the wheels on the same dyno. An XU9J4Z Mi16 (145hp) makes 75kW (100hp). A GTi180 approx. 100kw (134hp). Just pointing out the differences between dynos.

Edited April 17, 2007 by petert

[DrSarty 90 1 Cars]

I think this is a clear indication again (my current biggest rant), that a horsepower figure is relatively meaningless.

 

These graphs, which I too now get great interest in 'reading', tell a story of how an engine performs.

 

However I feel that this is still only telling half the story because this isolates the engine in one gear to produce the results, is widely open to differing (often disappointing) results from various rollers and operators and doesn't reflect how the car as a unit may perform in a certain environment (e.g. hill climb etc).

 

Sandy's massive two jumps in output might make for a really, really enjoyable drive. Alternatively it might be a bitch to live with IF it was just a road car. However on rallies for example it might be magnificent having two instant powerbands to sit on and use when need be.

 

I firmly believe that an objective 'rating on tractability' figure might be more applicable to show how smooth and useable one engine might be in comparison to another, if you ignore gearboxes and intended applications. I suggested using the top *15% of torque (or BHP)* / *for what percentage of the total rev range* as a rating, would mean smoother, or even fairly long duration, plateaud torque delivering engines would have 'better' ratings than others that might just produce 10BHP more but in a very different manner.

 

My mate's Golf VR6 with a little tuning made 158BHP at the wheels the other day. They standardly produce 175BHP at the fly wheel, but the calculated ATFW figure was 207BHP; a dynamic loss (?) of 49BHP!! This means a 160BHP Mi16 RR ATW figure of 120BHP is not wholly unreasonable or unacceptable.

 

Ready to be shot down

 

DrS

Edited April 17, 2007 by DrSarty

[gti_al 1]

An XU9J4Z Mi16 (145hp) makes 75kW (100hp).

 

So that means your stage 1 is 20hp atw above standard? That is pretty good... My head should be finished this week, so the bottom end is next. I was considering leaving it standard, but it seems stupid to if the gains are that substantial.

 

Jeff R said raising the CR was the best mod he had done when i saw him the other day too... his engine is porn, even if underforming, so that is encouraging.

Edited April 17, 2007 by gti_al

[Sandy 189]

I would have preferred a smoother curve on that one, but there was no scope to play. The step up onto the power was apparent on the road, made it quite exciting and the customer is certainly pleased with it. Next time, unless pistons are in the budget, I'd go slightly milder on the cams and trade some peak for a stronger/smoother mid range.

[veloce200 3]

Anyone read Performance Tuner this month? Comparison of rolling roads? The only one that seemed bang on was the Dyno Dynamics one. SPC in Sussex rr'd my std 8v (well Emerald ECU) and it produced 99hp at the wheels, 121 flywheel corrected. So i'd say that concurs with the Performance Tuner article. It's therefore largely pointless comparing engines on different types of rolling road as in the test there was as much as 15hp difference at the wheels on a low power engine.

[petert 554]

Spot on. UK drivers would be appalled if they put their car on an Australian dyno. The only way to compare things is with a known reference. eg. know what a fresh Mi16 puts out. My new engine might put out 225hp or 200 hp. You wouldn't know. I never take any notice of flywheel hp figures that are derived from a rolling road. I don't even try to apply Puma's formula. It's absolutley meaningless. You'd have to have one for UK dynos and one for Aussie dynos. All that really matters is that you go out with more than when you came in.

Edited April 25, 2007 by petert

[NNN 1]

Maybe a bit off-topic, but has anyone used or tested street dyno or home dyno with positive/negative results??

Edited April 25, 2007 by NNN

[veloce200 3]

Spot on. UK drivers would be appalled if they put their car on an Australian dyno. The only way to compare things is with a known reference. eg. know what a fresh Mi16 puts out. My new engine might put out 225hp or 200 hp. You wouldn't know. I never take any notice of flywheel hp figures that are derived from a rolling road. I don't even try to apply Puma's formula. It's absolutley meaningless. You'd have to have one for UK dynos and one for Aussie dynos. All that really matters is that you go out with more than when you came in.

maybe that's why they are so good at sport - constantly being told they are worse than they really are gets them motivated

[taffycrook 2]

Anyone read Performance Tuner this month? Comparison of rolling roads? The only one that seemed bang on was the Dyno Dynamics one. SPC in Sussex rr'd my std 8v (well Emerald ECU) and it produced 99hp at the wheels, 121 flywheel corrected. So i'd say that concurs with the Performance Tuner article. It's therefore largely pointless comparing engines on different types of rolling road as in the test there was as much as 15hp difference at the wheels on a low power engine.

 

I have not read this article as of yet but I can imagine how it reads.

I work for one of the big rolling road companies selling this gear. Or at least till the middle of next month I do anyway.

Most of what I have read or is on the web is a long way from fact. I have in the past tried to explain that a ruler is only as accurate as the person using it but if a ruler can be wrong how do you expect a vernier to be any better.

Most modern rolling roads are capable of repeatable results, if maintained and calibrated they will be accurate enough for most applications.

Anyone who can guess losses using a formula or witchcraft is as daft as Mac mad the mad man. Or does not unerstand the prinicple of rolling roads.

The idea of correcting to a DIN standard allows results to be compared anywhere in the world. But the corrected figure is only given with the flywheel figure.

believe what you want but never believe everything you read.