[Track_Prep] 205 Gti-6 Track Car Build

[Jolly Green Monster 51 1 Cars]

so it is, now I look properly.. thanks.

 

you could wire that to run wasted spark on the 4 gti6 coils then.. hummm...

 

arrrhhh that makes much more sense.

 

Going to struggle to get a vf22.. but you could get something close, I notice now in your signiture it says its a 2.5 so I presume mapped already so might be easier in the long run to just buy what you can get and get it tweaked.

 

I was assuming it was for a project car.

 

Simon

[rallyeash 155]

Yeah the Impreza is on Apexi ecu with commander.

I was going to ring around a few Impreza breakers to try and source something. I didn't really want the expense of anything more than a replacement turbo. Id rather a rebuild kit for mine because I know its sorted then rather than buying a used 13 year old ragged turbo.

[Jolly Green Monster 51 1 Cars]

okay - might be worth trying MattyB http://www.ebay.co.uk/sch/mattybr5/m.html may have something

or Paul at http://www.hotfrog.co.uk/Companies/CCA-Developments_6248831

 

Simon

[Sandy 189]

Good work Ash/Craig!

 

It's always very difficult to advise people when I feel that something isn't right, but above all I try to give the advice that I feel is most appropriate to the circumstances and the probability of a serious problem occurring in the near future. When I did Pete's (Mad Prof..), I kept going until it was done as safe as I could make it, whilst still being driveable. Basically any more advance make the engine in that case rattle like a frantic paint can; but retarded as it had to be, it felt grumpy and driveability was poor no matter how the fuelling was tackled. Pete tolerated it as long as he could, but it was clearly not right and eventually had to take the engine and deal with the core issue.

In this case, we had air leak issues early on that prompted me to stop proceedings, so we could deal with the problem of the inlet sealing. Obviously I don't take decisions like that lightly, but mapping around problems like that is never going to produce satisfactory driveability and not my style. We got that sorted and I changed the inner injectors for smaller ones to improve the light throttle fuelling precision, but I was still seeing unstable/erratic fuelling, symptomatic of unstable combustion on one or mutliple cylinders, having only so far worked on light load areas of the maps (I do that first then work outwards to the higher risk areas once I've got a good impression of what the engine wants). At medium load around 2000-2500rpm I was having to pull the ignition back to very low figures to calm the rattling, which sometimes can be a local issue so to speak (ie Honda VTEC engines on bodies are commonly like that), but working up to around 4000rpm it was still unable to tolerate reasonable advance figures and I gave Craig the option of continuing, but advised against, because I knew that isn't was some way away from safe.

I should qualify this a bit, because some of the comments above read a bit like there might be a suggestion of me "walking off the pitch" or not understanding the nature of a high CR engine. For those of you that don't know, I map a wide variety of edgy, high CR race engines on an almost daily basis on engine dynos, rollers and live testing, the most extreme/barely mappable including a 14.5:1 CR 1800 X-flow with siamesed valve seats on 97RON and 12.7:1 1 bar supercharged VCT Honda K20, none of which show any signs of det or overfuelling on strip down. The number of standard/fast road spec XU 16 valvers on bodies I've done is way beyond counting, so I know what they should be like and each is mapped from scratch to be sure I do the best I can with it. If I advise stopping and reviewing the engine, it's not going to be without good cause!

Alot of people think you can pretty much keep upping CR and cure the problems with mapping and/or knock control; in blunt terms, yes you can, but beyond the optimum dynamic CR for the engine spec, you'll be losing out and risking damage, if not now, later when the conditions drift a bit from when it was set up. This problem seems to be most acute in mildly cammed, medium spec engines and the relative ignorant abandon of "engine builders" who just screw the parts together without any need to be concerned about what happens one it's out the door, doesn't help. If you buy an unknown engine, you're sadly vulnerable to these problems or in Pete's case you put your faith in a supposedly reputable parts supplier, to get their designs right to save you the agro and when they don't take enough care about what they do, you have a nightmare on your hands.

 

Hopefully Thursday will work out better!

[Jolly Green Monster 51 1 Cars]

Thanks for clarification Sandy. As I tried to say previously its clear you know your stuff but I couldn't see how it could be too high but your explanation clears that up. As has been said previously it sounds like it was trying to be a diesel engine

Good work Ash/Craig!

 

It's always very difficult to advise people when I feel that something isn't right, but above all I try to give the advice that I feel is most appropriate to the circumstances and the probability of a serious problem occurring in the near future. When I did Pete's (Mad Prof..), I kept going until it was done as safe as I could make it, whilst still being driveable. Basically any more advance make the engine in that case rattle like a frantic paint can; but retarded as it had to be, it felt grumpy and driveability was poor no matter how the fuelling was tackled. Pete tolerated it as long as he could, but it was clearly not right and eventually had to take the engine and deal with the core issue.

In this case, we had air leak issues early on that prompted me to stop proceedings, so we could deal with the problem of the inlet sealing. Obviously I don't take decisions like that lightly, but mapping around problems like that is never going to produce satisfactory driveability and not my style. We got that sorted and I changed the inner injectors for smaller ones to improve the light throttle fuelling precision, but I was still seeing unstable/erratic fuelling, symptomatic of unstable combustion on one or mutliple cylinders, having only so far worked on light load areas of the maps (I do that first then work outwards to the higher risk areas once I've got a good impression of what the engine wants). At medium load around 2000-2500rpm I was having to pull the ignition back to very low figures to calm the rattling, which sometimes can be a local issue so to speak (ie Honda VTEC engines on bodies are commonly like that), but working up to around 4000rpm it was still unable to tolerate reasonable advance figures and I gave Craig the option of continuing, but advised against, because I knew that isn't was some way away from safe.

I should qualify this a bit, because some of the comments above read a bit like there might be a suggestion of me "walking off the pitch" or not understanding the nature of a high CR engine. For those of you that don't know, I map a wide variety of edgy, high CR race engines on an almost daily basis on engine dynos, rollers and live testing, the most extreme/barely mappable including a 14.5:1 CR 1800 X-flow with siamesed valve seats on 97RON and 12.7:1 1 bar supercharged VCT Honda K20, none of which show any signs of det or overfuelling on strip down. The number of standard/fast road spec XU 16 valvers on bodies I've done is way beyond counting, so I know what they should be like and each is mapped from scratch to be sure I do the best I can with it. If I advise stopping and reviewing the engine, it's not going to be without good cause!

Alot of people think you can pretty much keep upping CR and cure the problems with mapping and/or knock control; in blunt terms, yes you can, but beyond the optimum dynamic CR for the engine spec, you'll be losing out and risking damage, if not now, later when the conditions drift a bit from when it was set up. This problem seems to be most acute in mildly cammed, medium spec engines and the relative ignorant abandon of "engine builders" who just screw the parts together without any need to be concerned about what happens one it's out the door, doesn't help. If you buy an unknown engine, you're sadly vulnerable to these problems or in Pete's case you put your faith in a supposedly reputable parts supplier, to get their designs right to save you the agro and when they don't take enough care about what they do, you have a nightmare on your hands.

 

Hopefully Thursday will work out better!

[rallyeash 155]

thanks for the write up and clarification on it all Sandy.

I was a little worried that this thread would start turning into some internet debate...

[Sandy 189]

A bit of a side note kind of on the topic, but a good example. I'm currently helping an engine builder friend of mine evaluate a rival's cutting edge engine we've been given (sorry no names!) On the engine dyno, the advance table of the main map as supplied looked reasonable to us, perhaps a bit high at the top, until we checked the CPS lead angle and found it to be around 8 degrees retarded. With that corrected and the main map having the angle difference subtracted, the advance figures looked lowish. Around 2000-4000rpm is was pinking terribly at mid throttle, but as is often the case less so at full throttle (it's common for cylinder pressure at low rpm to peak mid throttle and drop at full throttle as the gas speed over the butterfly falls away). We didn't hang about there as damage was clearly not far away. The engine at peak torque was making approx 90lbft/litre and 81lbft/litre at peak power. On strip down, I got a phone asking me to come and look for a second opinion, because he was measuring it to be around 15:1 CR. I double checked it and it was about that, which really surprised us. The cams were a classic profile timed very conventionally, so it was pretty high CR. Some people think CR is a crutch for getting high torque figures, but with much lower CRs on the same dyno with our engines on 97-99RON we've seen up to 97.5lbft/litre peak and around 89lbft/litre at peak power. The point is, for good power and torque, you need efficiency and to beefficient you need a clean and complete burn of the charge. To achieve that, the charge needs to be well homogenised and optimum density. If the charge is not well mixed and cylinder filling is poor, raising CR will help to dense it up, so the flame front can find the next molecule quickly and burn more efficiently; which helps an inefficient engine work more efficiently. Flipside, if your charge is well mixed and cylinder filling good, you don't need to crush it as much to get a good clean burn, so high CR isn't productive.

As with all aspects of engine building, moderation is key and choosing parameters and components to work well together is much more productive than trying to max everything out. Well I think so anyway!

[stuart 31 3 Cars]

Good effort with the engine swap! And theres me whinging about fitting an oil cooler

 

Fingers crossed for thursday

[Jolly Green Monster 51 1 Cars]

A bit of a side note kind of on the topic, but a good example. I'm currently helping an engine builder friend of mine evaluate a rival's cutting edge engine we've been given (sorry no names!) On the engine dyno, the advance table of the main map as supplied looked reasonable to us, perhaps a bit high at the top, until we checked the CPS lead angle and found it to be around 8 degrees retarded. With that corrected and the main map having the angle difference subtracted, the advance figures looked lowish. Around 2000-4000rpm is was pinking terribly at mid throttle, but as is often the case less so at full throttle (it's common for cylinder pressure at low rpm to peak mid throttle and drop at full throttle as the gas speed over the butterfly falls away). We didn't hang about there as damage was clearly not far away. The engine at peak torque was making approx 90lbft/litre and 81lbft/litre at peak power. On strip down, I got a phone asking me to come and look for a second opinion, because he was measuring it to be around 15:1 CR. I double checked it and it was about that, which really surprised us. The cams were a classic profile timed very conventionally, so it was pretty high CR. Some people think CR is a crutch for getting high torque figures, but with much lower CRs on the same dyno with our engines on 97-99RON we've seen up to 97.5lbft/litre peak and around 89lbft/litre at peak power. The point is, for good power and torque, you need efficiency and to beefficient you need a clean and complete burn of the charge. To achieve that, the charge needs to be well homogenised and optimum density. If the charge is not well mixed and cylinder filling is poor, raising CR will help to dense it up, so the flame front can find the next molecule quickly and burn more efficiently; which helps an inefficient engine work more efficiently. Flipside, if your charge is well mixed and cylinder filling good, you don't need to crush it as much to get a good clean burn, so high CR isn't productive.As with all aspects of engine building, moderation is key and choosing parameters and components to work well together is much more productive than trying to max everything out. Well I think so anyway!

What sort of timing are you having to run to stop a 14.5:1 engine from rattling it tits off?

Obviously higher ron fuel may bring the higher compression into its own.

It also sounds like the high compression engines your are talking about are not necessarily well out together either, with poorly specced parts and badly built?

Edited November 5, 2013 by Jolly Green Monster

[Sandy 189]

The timing I'd expect to see depends on the engine overall and speed/loads, you can't judge it on a single figure. I see some pretty extreme engines, whether or not I think the specs are excessive, it's down to me to find out what makes them drive well and survive. Some of the engine builders I do that for have sensible, moderate views and some like to push the edge to see what it brings; those experiences are much of what teaches me to be moderate! I have to say, after extensive, exhaustive testing, although high octane fuels help to make high cylinder pressure engines less edgy and usually benefit the power of boosted engines, the best atmo results I've seen across the board, have still always been on V-power. Race fuels and E85 change where the power is made, but overall I honestly have never seen a power improvement from them on atmo engines. With E85 the problems that can occur through the lack of lubrication and corrosion are very discouraging and the hassle of buying, storing and managing race fuels easily outweighs any meagre benefits for indvividuals IMO.

Edited November 6, 2013 by Sandy

[Jolly Green Monster 51 1 Cars]

I was only meaning a rough figure. Ie. there is still more that could be removed? Your not getting to not being able to remove more?

The subaru engines I play with daily you would hope to be around the 20degree mark at 6000rpm give or take a bit and depending on fuel and turbo used. Tend to find if the engines poor or compression too high when you get to 10deg to stop it detting it jist feels lathagic.

Obviously a high compression turbo engine is unlikely to even be as high compression as a na engine so a high compression na engine is going to be pushing massive cylinder pressure and from what your says of no benefit.

 

Simon

Edited November 6, 2013 by Jolly Green Monster

[kyepan 291]

impressive engine swap time!!! i was going to say could you not run a set of cams with more overlap, or use a thicker head gasket? but it seems you have a spare engine? or did i miss something...

[kyepan 291]

Ps another well done for not giving up easy! from one throttle bodied xu engine owner to another, it's worth it, every time you open the throttle and listen to the glorious fanfare, i know i harp on about this all the time. But it still makes me smile every time.

[kyepan 291]

Hows it going so far today?

[Jolly Green Monster 51 1 Cars]

Clicked notification mail hoping for good news

[welshpug 1,622]

SRD?

 

Will be interesting to hear the rough wheel figures, heard of some very impressive figures on a standard gti6 engine that Will DiClaudio had made his own inlet for, far longer than most utilising the full curve of the gti6 inlet and shorter trumpets.

[rallyeash 155]

Ecu failed on the rollers

[TT205 42]

Jesus talk about bad luck

 

Did you murder a Nun in a former life?

[Jolly Green Monster 51 1 Cars]

Wtf

[TT205 42]

Just thinking out loud - so did the previous engine really have excessive compression or could the whole thing be down to the ECU?

[rallyeash 155]

No the engine was running fine and the ecu was too.

We drove a few miles yesterday night too. It's a fairly common thing on DTA ecu's

[rallyeash 155]

Another ecu fitted and the mappings currently happening. Fingers crossed

[kyepan 291]

how did you manage to find another ecu so quick?

 

What dta was it as i have an s40

[rallyeash 155]

No it was a E48. Sandy had a spare at his house so will be used for short term till Craig's is sorted.

[Jolly Green Monster 51 1 Cars]

Nice one. Hope all good well now.