Rolling road section

Hi, just a link that I thought ought to receive some more attention 413bhp!!!

Joe

Joe - I've been watching this for a while. I know you've pushed your car regularly on high boost and despite your best efforts you have yet to nuke the standard internals. Are they going to go progressively, or just go pop if they are out of tolerance?

of the high powered cars we know that had piston failiures do we know how many of them were mapped, and if they were mapped, then how aggressively? Is the issue the boost pressure if the car is mapped a good few degrees off det?

I think that Nyssa7 could give some valuable input to this, but have not seen him post recently?

I'll bet most of the piston failiures is due to weak mixture.. ie monkey business done somewhere along the line.

Now that we have good discussion on going , one question of EGT values.
In my case I can feel the car runnning much stronger, when I have EGT above 900 degC. Under it, I can clearly feel that something is braking my driving.
Joe or anyone elese with EGT, can you feel anything like that and what is normally your EGT values when pushing hard?
I have warning light in 960 degC and once or awhile it goes near 1000 degC, especially near and above 7000 rpm with 4th or higher gear.

- Jari -

EGT = Exhaust Gas Temperature?

Can i ask the usefulness of this? Another toy wouldnt go a miss!!

Ross

@ jari

impressive results.....:-)

you are running standard injectors ?
how is your afr especially in higher revs and gears ?

how is spoolup / full boost with your 3071 ? i think you are running 0.86 t25 turbine housing, right ?


macki

I would feel pretty confident in saying it is fueling and detonation that cause the engine to let go more than outright boost.

EGTs give you an idea of combustion temps. Too high and you are likely running too lean (or too much boost/backpressure) which means more chance of detonation and melting a piston.

Hi Jari, despite my best efforts, I have not managed to get the EGT's to go above 900degC , only once! , I have heard that pistons start to melt above 950degC, so I have always considered 900degC as an upper maximum, although some highly tuned turbo cars do treat 1000degC as the limit.

When 'racing' an EVO FQ400 at Cadwell, I saw just over 900degC after a couple of laps of enthusiastic driving at 1.4 bar boost, more boost would have seen higher temperatures. I suspect, you are getting a little bit of detonation there pulling back the ignition timing, the Coupes det sensors are very sensitive!, I've seen them pull back timing, even when the driver wasnt aware.




I think both can happen, I've seen Geoffs Coupes pistons, a car running 1.4 bar regularly with a standard inter cooler, they didn't go bang, but the car got more and more smoky, and when the pistons came out the pistons had not melted, but the rings were all cracked and damaged and numerous micro fracture were seen between the crown and the first ring, the rings were so damaged and gummed up, they would not be sealing well atall!

Joe

Don't think my nfirst engine was mapped that aggressively, but equally don't suppose the 1.6 bar was doing the rods any favours! Also highly possible a missed gearchange contributed - we'll never really know

At the end of the day, if people want to build 400+bhp engines with stock internals, then fine. At least when they do let go, they can just plug another one in

Trevor - If I remember right you managed to put a rod through the block? What Bhp / torque were you running, also what rev limit / boost at the redline? I'm not disputing that if you go for big power on the standard internals then you have to be prepared for something to let go - but I am interested in what the reasonable safety margin is before this point, if we really dont know then so be it, but there's no harm in trying to find out.

This post is interesting to me as I have forged pistons but not rods. My car is 'running in' at the moment and I will be booking in for its final map with PT very soon. It has the potential to run very high figures however does anyone suggest a limit in BHP and FT-lb and Boost that I should run? Does PT monitor EGT when they map?

Ask rob at PT about the EGT monitoring. I believe the weak point on your car would be the rod bolts (thanks JohnS and others). The general consensus would be not more than 330 lbs / ft to be on the safe side, and not higher than 7,300 rpm as long as you have a balanced engine (gained from talking to as many people as I can – both on here and elsewhere, not through personal experience). Boost at the redline around 1.2 / 1.3 bar IMO (GT28R will probably hold about 1.2 or slightly less). You can ask rob to map the car to take into account the cap on the torque.

Thanks for the useful info. I am looking for a fast spool up and quick acceleration from stop right through midrange. I'm NOT interested in top speed or raising the rev limit even thought the engine is fully balanced.
I agree with you I feel that my only weak point is the Rods and rod bolts.
Turbo is the GT RSR.
My clicky below shows all the work done.
Barbz said that Nigel ran about 380lbs but told PT to back it down to about 340lbs as his turbo could easily hold it to redline. I feel I’m in the same boat as Nigel but with a smaller turbo. I just want the opinion of the forum before going to PT as I don’t want rob to push it too far.

Is the figures you guys qoute at the wheel?

It will be flywheel figures being quoted.

If you have the RSR, it will be around 320/330lb/ft that you'll be producing anyways, so i dont think that will cause a problem, according to suba and others.

Ross

I think someone got 340 lb-ft with the RSR, but that was at 1.7bar! You should be expecting 300 lb-ft with a more conservative 1.4bar edit: maybe a bit more if you have headwork.

I think that was Marcus - forged engine with nos thrown in for good measure.

Ok last point as I don't wanna highjack this thread too much
The RSR together with the headwork/Cams/Higher CR/H&S downpipe etc the power should be higher. I was thinking of setting the bar at 350lb and dropping the boost towards redline. Is that pushing too far?

1.7 + RSR = marcus.

This is giving me food for thought about stnd internals, but IF myself or Suba do decide to push the limits of stnd internals in this country, presumably a EGT is a worthwhile mod to try and install some safety into the system so we dont fry the pistons?

Ross

Isnt it a lower compression ratio you would be looking for? Also 350lb/ft is gonna bend the rods according to the experts. With headwork and cams etc there is the high possiblity that you will get near that figure but whether or not its safe to do so... although stnd internals in finland holding 347lb/ft...

When mapping yes - but tba I never really look at gauges when I push the car, always try to, but forget somehow. If it had an audible warning set up then it could be useful...

As most now know, i have my "worry gauge" and it keeps me occupied a lot of the time. Im running around 1.45 bar midrange, and my fuelling has re-adjusted itself to running high tens again (10.7/10/8) whereas at redline is running 11.9/12.0. Now i know i have the extra fuelling available because i can turn the boost up at redline and it will actually run richer (11.6) but can i up the midrange to see if its going to lean it out slightly more? 1.5 bar? I know Dr Frag runs that kinda power, but its always been labelled as bad bad bad. Would an EGT gauge show me whether or not im able to run this or not?

Ross

No, The compression now is 8.8:1



Actually he’s claiming 361lb/ft with the T04

Ok I’m going to set my limit at 340lb/ft with my fingers crossed

TurboJ, it will be very interesting to see how you get on with the RSR turbo.

Both myself and Flea got 330 lb/ft with the larger Gt28rs at 1.5 bar at the height of summer., mine was at the end of mapping at 38degC!, with a slipping clutch, the Coupe now feels a lot quicker , very noticeably so, but how much extra I don't know , but I suspect 330-340 lb/ft.

There's no point in going for huge torque/power figures on the rollers at high boost levels if you're never going to run them on the road,..... the RSR, should have a compressor efficiency between the R and the RS, so although a one off blat at 1.5 bar+ would be fine (as the intercooler heat sink will soak up most of the extra heat), it would soon overwhelm it and start to become too risky for the engine.

I would consider setting your boost level for your mapping at what you intend to run and according to the compressor map, so 1.4-1.5 bar would be a good maximum ,as its considered best not to go below 70% efficiency on the turbo, although many do push their smaller turbos way too hard ( I have been one of the most guilty of this! ).

Joe

Thanks Joe, I have had the same discussion with Barbz and he is not sure as to what my figures might actually be. He was really impressed with the level of headwork and inlet porting and he thinks I will produce a lot of power. All my parts came from TI except the machining work and actual engine building.

My intake charges should be low as my intercooler is a custom tube & fin design with a good surface area exposed as well as a water injection system.

1.4-1.5 sounds good for peak but I would drop it off nearer redline.

what kind of clutch will you be running j? are you going for a paddle item?

Barbz reckoned when i was speaking to him to run around 1.5bar 3k-5.5k revs and then drop it off to around 1.25bar above this..but its all to do with how much my std injectors will fuel for i suppose, and how much torque my clutch with hold midrange

Iain

I'll be using the 16VT injectors @ 3Bar.

Clutch is another thing. I've got the uprated walkers/GTA combo but I’m 95% sure it's gonna slip. If it does then gonna have to save my pocket money for the twin plate jobbie.

1.5Bar from 3K-5.5K is perfect then drop off the boost. It’s just how much torque will I be chucking out at 1.5 that worries me??? Guess only time will tell.

i will be using std. ones at 3.8Bar..

My clutch is also Walkers/GTA combo.. i took out my walkers paddle because it was horrible to drive, so i will get the torque dropped to stop slip hopefully..

Torque man i havent got a clue, i havent driven the car over 0.9bar yet until i know its safe

That clutch is rated to 300 lbs / ft only - Joe used to run is and had slip over 320 lbs / ft. I dont think it'll do the job.

wont the 16vt injectors create idle difficulties? Why not go for 20vt injectors with 3.8 bar fuel pressure?

yeah i know.. but i suppose all these rating depend on your driving style etc. so i will have to get PT to detune the torque to allow me to run this on my car, but as for Turbo J im not sure it will do his job

I'm in the same position - but there's no way I'm having the car mapped and telling them to stay below 300 lbs /ft or going to waste a days mapping time and money with a clutch that's not up to the job only to have to replace it and then come back and do it all over again.

Guys remember the Helix group buy Paddle or Organic.

Ross