S12 rallye with TU5JP4 mildly modded rolling road results

24th May 2010, 20:29

The mileage on the car was 92,869 miles.

Put my car on the rollers today at a rolling road recomended to me by a mate in work as the guy who runs the rr knows his stuff and the rolling road is know for giving proper figures not made up one you see. So i went there expecting around the 135-140bhp mark from my mildly tweeked TU5JP4 engine. The spec is as followed.

32,000mile standard JP4 engine,
J4 cams and pulleys,
Lightened flywheel (0.5kg lighter),
J4 valve springs abd buckets,
K&N pannel filter in a GTI airbox,
4-2-1 heat wrapped four branch raceland mani,
Full pugsport 2" de-cat exhaust system.

On the first run it made a massive 153bhp at 7,310rpm and 112ft/lbs toqure at 6,739rpm so tommy then proceeded to swing the cams in search of more power but after a few runs it was clear tht they were set to thier optimum at the begining. So he then continued to give the engine a health check by checking the compression and re-check the fueling of the car to see if it had changed since the begining of the sesion. All the cylinders are holding pressure prefectly although he did say the valve stem seals are just alittle leaky when the car is first started. The engine was run on another software system to check the power figures were right and it came out at 151bhp so i'm extremely happy with that. Vidoes The two run i got videos of weren't accurate as the limiter was hit hard but they are the only vids i have

First graph shows clearly that the bhp curve is still climbing when it hits the limiter. Tommy sugested that it might be an idea to raise the limiter by about 200rpm to the peak power isn't so close to the limiter. But that future plans.

Second graph

If you want to see the full spec of the car and how it started out over two years ago check out my blog.

http://www.106rallyeforum.com/forum2...ad.php?t=53212

24th May 2010, 20:32

very nice mate.....

24th May 2010, 20:33

them results are very good for mods, well amazing for mods bet you well pleased

24th May 2010, 20:35

Quote:

Originally Posted by dankzy

them results are very good for mods, well amazing for mods bet you well pleased

yeah it's a really strong engine. I'm really happy with it.

24th May 2010, 20:41

so this is on standard cams? and standard head?

153bhp at 7,310rpm and 112ft/lbs toqure at 6,739rpm

you sure your rpm was right, as on standard cams, no way will they peak out at 7k + never design to do that!!! also torque is very high on the rev range,

if it was on uprated cams like newman Ph3 then yer i would expect it to be there.

but on the dyno sheet at the bottom of the post it say it peaking at 6.7 which is closer to the the standard cams.

just check that all, as on standard cams it will not peak that high.

24th May 2010, 20:45

also that curve is very very straight, dont seem right for standard cams really mate,

if it uprated cams, then maybe need looking at to get a better curve?

24th May 2010, 20:48

Quote:

Originally Posted by AndySAXO

so this is on standard cams? and standard head?

153bhp at 7,310rpm and 112ft/lbs toqure at 6,739rpm

you sure your rpm was right, as on standard cams, no way will they peak out at 7k + never design to do that!!! also torque is very high on the rev range,

if it was on uprated cams like newman Ph3 then yer i would expect it to be there.

but on the dyno sheet at the bottom of the post it say it peaking at 6.7 which is closer to the the standard cams.

just check that all, as on standard cams it will not peak that high.

Well the new JP4 16v engine works on the low lift and long duration princeable with bigger inlet valves where as the old 106gti engine J4 works on the high lift short duration with smaller inlet valves. The J4 cams a full 1mm more lift than the JP4 cams. So the bigger valves with the higher lift cams will make good top end a mid range but there will be a loss at lower revs. So i think the results are correct as i have sat down and looked into it with a mate who knows his engines.

24th May 2010, 20:50

Quote:

Originally Posted by AndySAXO

also that curve is very very straight, dont seem right for standard cams really mate,

if it uprated cams, then maybe need looking at to get a better curve?

if i put uprated cams in it out of a J4 engine i think it would push the power futher up the rev range due to the bigger valves in the JP4 head

24th May 2010, 20:51

look at the wheel figures.

120bhp@wheels wich is the same as what i got with standard j4 engine with breathing mods.

24th May 2010, 20:52

Quote:

Originally Posted by dannygti

look at the wheel figures.

120bhp@wheels wich is the same as what i got with standard j4 engine with breathing mods.

What was yours at the fly then?

24th May 2010, 21:02

but you say your using standard j4 cams?? or the JP4 cams?? in the first post you using J4 ones,

still, it basiclly standard form engine, but the power cvure is way to striaght!!

24th May 2010, 21:03

Quote:

Originally Posted by freddy6868

What was yours at the fly then?

its hard to say as my clutch was dragging giving a false reading (about 190bhp lmao)

but going on the usual fwd calculations around 140-145bhp@fly.

24th May 2010, 21:11

Quote:

Originally Posted by AndySAXO

but you say your using standard j4 cams?? or the JP4 cams?? in the first post you using J4 ones,

still, it basiclly standard form engine, but the power cvure is way to striaght!!

Yeah using the J4 cams in the JP4 engine. Well it will be going on another set of rollers sometime and i will post up the results of that too.

24th May 2010, 21:12

Quote:

Originally Posted by dannygti

its hard to say as my clutch was dragging giving a false reading (about 190bhp lmao)

but going on the usual fwd calculations around 140-145bhp@fly.

So you would say the results from my car seam about right then?

24th May 2010, 21:18

well for a start the big valves will not push it up that high on the rev range, and is very very straight cuvre, well there is not cuvre really, not saying it worng, but seem alittle too straight will not be seeing the benefits of that power really dude, it be better if the power was alittle lower and the cuvre was better to be fair mate

24th May 2010, 21:21

Quote:

Originally Posted by freddy6868

So you would say the results from my car seam about right then?

im saying the wheel power is about right but the estimated flywheel figures are a little out. but who am i to say they are wrong?
the fly figure will only be a very rough guestimate and i personally dont look at fly figures.

24th May 2010, 21:24

Quote:

Originally Posted by AndySAXO

well for a start the big valves will not push it up that high on the rev range, and is very very straight cuvre, well there is not cuvre really, not saying it worng, but seem alittle too straight will not be seeing the benefits of that power really dude, it be better if the power was alittle lower and the cuvre was better to be fair mate

Yeah i know the power curve isn't the best as it still hasn't topped out at the limiter if you look closely. So i think i will have to look into either boddies to gain somemore mid range or some forged pistons and rods so i can rev it harded. Happy with the way it is al the moment though.

24th May 2010, 23:54

Very good results mate!

25th May 2010, 10:01

Quote:

Originally Posted by freddy6868

Yeah i know the power curve isn't the best as it still hasn't topped out at the limiter if you look closely. So i think i will have to look into either boddies to gain somemore mid range or some forged pistons and rods so i can rev it harded. Happy with the way it is al the moment though.

yer, you could do that, btu still want to power band better even on bodies, would say they are not standard j4 cams, with that cuvre.

but if you get the cuvre better it will drive better, and will be able to use the power better.

25th May 2010, 10:53

Some rolling road figures make me laugh!

Really cannot see how an engine with spec can achieve those figures. Are you sure they are standard J4 cams and not PH3's/708's? Peak figures seem far too high to be standard cams. Power figure also seems very high.

25th May 2010, 11:26

Quote:

Originally Posted by Finchowned

Some rolling road figures make me laugh!

Really cannot see how an engine with spec can achieve those figures. Are you sure they are standard J4 cams and not PH3's/708's? Peak figures seem far too high to be standard cams. Power figure also seems very high.

Thing is though J4 cams in a JP4 engine are completely different to J4 cams in a J4 engine. As he has stated above, the JP4 engine has larger inlet valves than a J4. If you put the 2 different types of inlet valves against each other you can instantly see the difference. That is why people don't tend to keep the JP4 cams in their JP4 conversion as the J4's have a higher lift (so essentially camming a J4 with standard cams - a very mild cam however). This will give the extra power and combined with decent breathing mods the power figure isn't way off at all! Yes, the fly wheel figure maybe a little out, I would still expect it to be above 145! Plus, I also believe that the JP4 engine responds better to breathing mods from past experience...

As you may know, even a breathed on J4 engine can reach <135bhp without cams, it all depends on how strong your engine is and what condition it is in.

25th May 2010, 11:43

also what RR your on!! haha

but it will not push the power up that high on the rev range, that is more ph3 708 power range, also the cuvre is too straight to get the full benefit of the power!

basiclly there noi power band, so will not be getting the best out of the car.

25th May 2010, 12:14

Quote:

Originally Posted by AndySAXO

also what RR your on!! haha

but it will not push the power up that high on the rev range, that is more ph3 708 power range, also the cuvre is too straight to get the full benefit of the power!

basiclly there noi power band, so will not be getting the best out of the car.

Lol, yeah the RR would obviously affect things but I don't see it as an exaggerated result.

Yes I agree with them 2 things as usually even on standard cams there is a bit of a surge from around the 4.5k mark. I don't really know much more than what i've said if I'm honest, would the larger inlet valves with the J4 cams 'tweaked' - so not on standard timing make the power higher in the rev range no?

I think looking at the graph, is that the lower/mid-range has a bit more power than standard creating the straight curve? Compared to the usual J4 graph that curves from 3.5-4.5k and tails off at 7k? As Danny said, the wheel figure looks pretty much spot on which is what most people go off

25th May 2010, 12:38

figures are just pub banter.

if the car feels good and performs well then that's ace mate personally I just see bhp figures as numbers on a sheet of paper.

25th May 2010, 12:57

yer, but looking at that cuvre it like what mine was from the the NMS RR day, and i struggle to use it all, and everytime i stiff gears it was rubbish, unsure on what box you are using, looking at your thread on the other forum, it a S2 box.

yer i agree BHP are pub talk, i was stating that the cuvre looks very straight, and something that i would be looking at getting better, even if that means losing some of the peak power to gain a better cuvre

sound like the cams are set for high bhp figures as the cam timing can be played with to get high bhp figures, but can be played with to get a better cuvre.

25th May 2010, 15:47

Quote:

Originally Posted by freddy6868

Well the new JP4 16v engine works on the low lift and long duration princeable with bigger inlet valves where as the old 106gti engine J4 works on the high lift short duration with smaller inlet valves.

oem jp4 cams have a shorter duration than j4 cams, so the above argument is invalid

25th May 2010, 15:50

Quote:

Originally Posted by Finchowned

Some rolling road figures make me laugh!

Really cannot see how an engine with spec can achieve those figures. Are you sure they are standard J4 cams and not PH3's/708's? Peak figures seem far too high to be standard cams. Power figure also seems very high.

Well it will be going on another set of local rollers soon to compare them but i hear alot of people come away from that rolling road with less than what they were expecting.

25th May 2010, 15:52

Quote:

Originally Posted by Harv

Thing is though J4 cams in a JP4 engine are completely different to J4 cams in a J4 engine. As he has stated above, the JP4 engine has larger inlet valves than a J4. If you put the 2 different types of inlet valves against each other you can instantly see the difference. That is why people don't tend to keep the JP4 cams in their JP4 conversion as the J4's have a higher lift (so essentially camming a J4 with standard cams - a very mild cam however). This will give the extra power and combined with decent breathing mods the power figure isn't way off at all! Yes, the fly wheel figure maybe a little out, I would still expect it to be above 145! Plus, I also believe that the JP4 engine responds better to breathing mods from past experience...

As you may know, even a breathed on J4 engine can reach <135bhp without cams, it all depends on how strong your engine is and what condition it is in.

plus the engine is very young and low mileage compaired to the older and higher mileage J4 engines that are about.

25th May 2010, 15:55

Quote:

Originally Posted by AndySAXO

yer, but looking at that cuvre it like what mine was from the the NMS RR day, and i struggle to use it all, and everytime i stiff gears it was rubbish, unsure on what box you are using, looking at your thread on the other forum, it a S2 box.

yer i agree BHP are pub talk, i was stating that the cuvre looks very straight, and something that i would be looking at getting better, even if that means losing some of the peak power to gain a better cuvre

sound like the cams are set for high bhp figures as the cam timing can be played with to get high bhp figures, but can be played with to get a better cuvre.

Well it pulls like a train up to nthe limiter and as soon as you change gear it's there again right to the limiter. I feel the s2 box is perfect for the engine on the track and on the road.

25th May 2010, 15:57

Quote:

Originally Posted by yr51ocw

oem jp4 cams have a shorter duration than j4 cams, so the above argument is invalid

Where did you get that information from? Even if this is true they still have a full 1mm of lift less than the J4 cam.

25th May 2010, 17:51

Quote:

Originally Posted by Harv

Thing is though J4 cams in a JP4 engine are completely different to J4 cams in a J4 engine. As he has stated above, the JP4 engine has larger inlet valves than a J4. If you put the 2 different types of inlet valves against each other you can instantly see the difference. That is why people don't tend to keep the JP4 cams in their JP4 conversion as the J4's have a higher lift (so essentially camming a J4 with standard cams - a very mild cam however). This will give the extra power and combined with decent breathing mods the power figure isn't way off at all! Yes, the fly wheel figure maybe a little out, I would still expect it to be above 145! Plus, I also believe that the JP4 engine responds better to breathing mods from past experience...

As you may know, even a breathed on J4 engine can reach <135bhp without cams, it all depends on how strong your engine is and what condition it is in.

Surely a JP4 head won't push the peak power up that high with J4 cams! That's PH3 territory. I find 120BHP at the wheels hard to believe on a breathing modded JP4/J4 combo personally.

We'd all like beleive our engines are pushing really good power but 153BHP from a JP4 lump with some breathing mods and J4 cams seems a little optimistic.

25th May 2010, 18:02

Quote:

Originally Posted by freddy6868

Where did you get that information from? Even if this is true they still have a full 1mm of lift less than the J4 cam.

With a little research. Specs for the inlet cams are as follows

J4 duration @ 0.1mm - 252 degrees
JP4 Duration @ 0.1mm - 242 degrees

J4 duration @ 1.0mm - 212 degrees
JP4 duration @ 1.0mm - 199 degrees

J4 peak lift - 8.49mm
JP4 peak lift - 8.00mm

It pays to be a little more accurate when defending yourself, forum hear say is a dangerous thing. However I too run an engine with almost identical spec to yours and have figures slightly higher, albeit at lower rpm than you. These figures I took with a pinch of salt

25th May 2010, 21:15

interesting that i got 1 or 2 bhp higher on a vts engine with breathing/exhaust mods at the wheel but translated to 12 bhp less when corrected to the flywheel

similar curve, just going straight up until peaking at about 7k rpm. Peak torque was at about 5.5k though

26th May 2010, 19:24

Quote:

Originally Posted by yr51ocw

With a little research. Specs for the inlet cams are as follows

J4 duration @ 0.1mm - 252 degrees
JP4 Duration @ 0.1mm - 242 degrees

J4 duration @ 1.0mm - 212 degrees
JP4 duration @ 1.0mm - 199 degrees

J4 peak lift - 8.49mm
JP4 peak lift - 8.00mm

It pays to be a little more accurate when defending yourself, forum hear say is a dangerous thing. However I too run an engine with almost identical spec to yours and have figures slightly higher, albeit at lower rpm than you. These figures I took with a pinch of salt

what lift are the after market cams for the j4 engines then as the cams i put in deffo had a full 1mm of lift over the jp4 cams as i measured it with a vernier.

26th May 2010, 19:53

Quote:

Originally Posted by freddy6868

what lift are the after market cams for the j4 engines then as the cams i put in deffo had a full 1mm of lift over the jp4 cams as i measured it with a vernier.

and a dti plunger.