Rolling Road Graph Thread - Post Your's

[Vili 18]

Do you have any idea of the compression your running in the engine?

Is the head close to the wear marks? Did you skim the block? What type of gasket?

 

If you asked me. The compression ratio is roughly 11.6. I didn't measure the actual figure. Head gasket is MLS the oe. GTI-6 one.

I didn't skim the block. The head is skimmed only very little 0,2 mm or so.

The compression ratio is at the very edge or past it. Ignition curve is retarded quite heavily at the lower revs and mildly at the middle high area. You can see the heavy pinking in the AFR curve at low revs and at 5000rpm. I had to retard the ignition curve even more after I did some further mods to inlet manifold. Despite the changes in the ignition curve the car made 5-7hp more between 4500-7000. I don't have exhaust temperature sensors so I don't know if I'm dangerously high or not.

[Jolly Green Monster 51 1 Cars]

gti6 engine

 

 

Simon

[stu8v 68 1 Cars]

[petert 586]

Here's an interesting pair of figures, for Parry's engine which I've just finished rebuilding and was tuned today. The blue figures are for the original 11.25:1 XU9J4 which spun a bearing and died. The red figures are for a 12:1 XU10J4, same XU9J4 head as before, but with a slightly smaller inlet cam. We built it for torque. Nice figures, right? Except it's HP at the wheels. The dyno operator only does race cars and he rates it as the 5th best N/A 2L he's ever done.

[JeffR 51]

Very nice Peter. That's up around the 245hp @flywheel. What fuel is he using at 12:1 C/R?

[petert 586]

Unleaded 98. Parry was told 244. I thought 246 and you said 245. Even if it's anywhere above 240hp, it's silly hp to be making at only 6700 with a 2L.

[parry 23 1 Cars]

Thank you so much Peter....The best part about the build, no oil leaks, no issues on the Dyno. My tuner is a cranky bastard when cars are not prepared right. My car was perfect, thank you Peter and Adrian... No wonder I was not allowed to touch the car....

 

Now the test, can I get a pb with 20 more HP....

[kyepan 291]

this is really interesting, care to share anything more about how you achieved the compression peter?

[petert 586]

Decked and o-ringed block, thin copper head gasket.

[Anthony 1,003]

Looks like a massive gain for what is presumably "just" an extra 93cc, a few % more CR and a bit less inlet cam.

 

Any thoughts as to why it's such an improvement relative to the changes, assuming the old engine wasn't tired or whatever?

[petert 586]

It's probably due to a number of factors.

 

Reduced squish height

Flat top piston rather than dome piston for better flame travel

Larger bore unshrouds the 36.4mm inlet valves better, improving inlet flow CFM. Previously, copper gasket and liners were eye-browed.

 

Everything else remained the same. ie 48mm TB's on Satchell inlet manifold, XU9J4 exhaust manifold and dry sumped. The original engine was brand new. A failed relief spring in the dry sump pump caused the death.

Edited February 5, 2015 by petert

[kyepan 291]

which pistons did you use?

[petert 586]

Forged Wiseco.

[petert 586]

Fairly pleased with this one. After blowing the race engine a few months ago, we had to come up with something quickly for the final round. Look no further than the XU10J4 from my recently scrapped Mi16 daily driver. It's bog stock, other than my Stage I inlet cam, 48mm TB's and dry sump. It's even got the standard cast iron exhaust manifold. It roughly equates to approx 210hp flywheel. Contribute a reasonable portion to the dry sump. Ignore the AFR's on the chart. It was 12.5-12.7 across the range. I just love these engines.

 

117kW @ 7100

Edited September 26, 2015 by petert

[Cdrom 0 1 Cars]

Mi16 engine xu9j4

AT power bodies

Catcams fast road inlet cam

BHP @ wheels was 180bhp

[Andy 105 1 Cars]

S16 engine with AT bodies , Emerald and Peter Taylor hydraulic cams and 96mm crank ( hence the torque ) 

[16v205 9]

2x graphs overlaid from my engine. Was mapped 11 years apart, the second time around it has a completely different inlet manifold setup which now fits under a bonnet.

 

Light & dark green is new inlet setup, red and blue is from 11 years ago.

 

[petert 586]

Interesting. How did they differ?

[wicked 103 3 Cars]

Looks like the RR is just filtering out the power numbers more. Only missing a bit of peak power at 6500rpm

Torque is just the derivative, calculated from the power graph (how much power changes per rpm) and much smoother if the power is filtered more. 

[petert 586]

It was a sad day last Saturday, in 41 deg heat. We were nearing the end of the dyno session, with the AFR’s looking good and ready to start fine tuning the ignition. Power was approx 132kW @7500  (at the wheels) and still climbing. Then all of a sudden, the dreaded #3 rod bearing let go. So cruel. Scrapped a steel crank and an expensive locally made rod. Oh well, back to work.

[Andy 105 1 Cars]

This is a tragedy. Very sorry Peter.