Club G40 Forum
Technical => Engine and Transmission => Topic started by: dan1300r on January 27, 2013, 11:15:16 am
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Currently my Polo Breadbin consists of the following platform (keeping it simple): 1341 bottom, standard valve size ported head, ported g40 inlet manifold, original G40 cam, DTA S40 management, G60 injectors, Golf 1.8 throttle body for TP Switch function.... It's Full blend Lader is giving hideous boost at 1800rpm and is walloping tyres and driveshafts even with a boost/vacuum controller + dump valve setup to dump some boost low down. These Laders seem to take some managing without the original bypass/throttle body.. Anyway I prefer the progressive spool up of turbo setups so I now have my K04 bolted up and am scratching my head at cam choices.. I know big turbos on little motors come with big lag hence why I've kept the G40 inlet manifold/std valve size - I want to keep fast low down airflow to reduce lag. I'm not in the budget for building hybrid turbos so will have to make do with the K04 I found in the parts bin. Some say GT cam with big turbo will spool it up quick and then die at 4500.. I don't know.. Will the G40 cam further exaggerate this?? I hear that n/a cams are best (like GT) I also have on the shelf a 1043cc std cam.. Anyone used one of these...?? It's a minefield! I've probably opened a can of worms now! Would be nice to hear what you lot have to say.. Thanks in advance.
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Out of all the OEM cams, the Polo GT (3F engine) is the best to use. With a K03 though it'll give a 1500-4500rpm powerband, though I've mapped a K03'd car with a 3F cam that had more like a 2500-5500rpm band but it had a lot of headwork done and machined-down NZ pistons so various engine characteristics had changed as a result.
I'd try a 3F cam with the K04, but be prepared to go for something longer duration. Piper do a 254°/254° that might be a good compromise. G40 original cams are crap with turbos, and the stock 1043cc and 1272cc SPI cams are pretty useless too - choke up way too early. 3F cam is a good match to a bigger turbo like a T25.
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Aah I spotted the piper 254/254 and raised an eyebrow... At a guess, where do you suppose my power range would be? Also looked at the Shrick 264/260 and 268/264... I'm somewhat tempted by the 264/260 if I can't get hold of a 3f.. I was in thinking that with the 1341 bottom and merely cleaned/smoothed/shaped (not so much opened up) ports to matched inlet I should have good fast low down venturi for good spool up, but also thinking that with the smaller inlet manifold that it may be pointless going up to the 268 down to not having the best flow characteristics high RPM thus not getting the full potential from this cam.. How does this sound??
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Loads of info here
http://www.g-laderseite.de/forum/viewtopic.php?t=2121
http://www.g-laderseite.de/forum/viewtopic.php?t=12519
Hows your german ;)
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It was the G-laderseite boys wanking over 3F cams that made me try one after finding the PY, AAV and PSD '1341' cams were shite with a turbo. The K03 needs a lairier cam though, but a 3F item seems to work well with a bigger turbo.
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Great stuff, I will try and find a 3F cam first port of call, they don't seem to be popping up on ebay.de this week, will have to keep an eye out or if anyone has one?.. For now, I'll have to see how it goes with the 196deg std cam that came from a carbed 1043 HZ, May be better than we think with a big turbo? Not even going to try the G40 cam.. I'm also using a thin ish 1mm head gasket so with the higher CR (aprox 8.3-1?) it may not be too bad off boost either.. Thanks for the input.
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I must add that I'm not looking for big HP, more of a driveable car so I'm thinking that with the 'useless' n/a cam this may help? (Andy)... Maybe it will boost too hard and too low like the G Lader did? I kind of expect with this set up it may make a lot of torque lower down and may peak circa 180hp at 5500.. I know it's a stab in the dark but I will post the dyno results once it's set up.. Will be a couple of months yet..
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This makes me wonder what cam would be best for a 1341, p&p BVH, 51mm TB etc etc with GT25 ... i have a shrick turbo cam in at the moment, anyone any experience in what the difference is like between that and the 3f GT unit anyone?
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What GT25 variant do you have?
Yoof runs the GT2554R, seems to give 4-7k powerband with a 268° cam which is great on track - would be interesting to try it with a 3F cam and see if that lowers the powerband at all.
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i have a gt2554R as well... i'll be starting with the shrick cam but wondered if anyone had any experience with both on a high spec build. i need to get the thing running before i worry about which is better really lol... ::) interested to know though..
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Just a quick one; on which rpm 2554R start to spool ?
Cheers
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I now have a dyno result: Ran the 196deg HZ cam with a K04-015 turbo (the one with the small/K03 hot side) at 1.2 bar and got 218ftlb torque at 3100rpm and 172bhp @ 5100rpm (not too far from my 180@5500 prediction). Tried to add another few PSI and the power fell right off, so the cam is choking it up after here but what I do have is boost starting at 2200rpm and holding full boost from 3500rpm right through to red. No lag is noticeable, it drives like an with a nice straight line on the graph. Lovely silky drive. I still want to see what the GT cam does.. Additionally, does anyone know how much better a GT inlet manifold will be over a ported G40 one? I know it may help ultimate HP but I'm worried the extra flow may increase lag?
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Nice Dan- what boost pressure is that at?
Boost low down is good, but the gearbox really won't thank you :-*
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I have attached dyno printouts for my breadbin as it has progressed, I have added notes on each as to the platform I have used, I have a drop-off and pick-up on the GT cam and inlet run due to wheelspin, not a flatspot.
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I now have a dyno result: Ran the 196deg HZ cam with a K04-015 turbo (the one with the small/K03 hot side) at 1.2 bar and got 218ftlb torque at 3100rpm and 172bhp @ 5100rpm (not too far from my 180@5500 prediction). Tried to add another few PSI and the power fell right off, so the cam is choking it up after here but what I do have is boost starting at 2200rpm and holding full boost from 3500rpm right through to red. No lag is noticeable, it drives like an with a nice straight line on the graph. Lovely silky drive. I still want to see what the GT cam does.. Additionally, does anyone know how much better a GT inlet manifold will be over a ported G40 one? I know it may help ultimate HP but I'm worried the extra flow may increase lag?
I hope my memory served me well when I wrote this down! I have now posted my dyno results - I wrote this from memory as I remembered my dyno man telling me over the phone... All will see how my memory served me.. I don't like to tell lies if I can help myself
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I now have a dyno result: Ran the 196deg HZ cam with a K04-015 turbo (the one with the small/K03 hot side) at 1.2 bar and got 218ftlb torque at 3100rpm and 172bhp @ 5100rpm (not too far from my 180@5500 prediction). Tried to add another few PSI and the power fell right off, so the cam is choking it up after here but what I do have is boost starting at 2200rpm and holding full boost from 3500rpm right through to red. No lag is noticeable, it drives like an with a nice straight line on the graph. Lovely silky drive. I still want to see what the GT cam does.. Additionally, does anyone know how much better a GT inlet manifold will be over a ported G40 one? I know it may help ultimate HP but I'm worried the extra flow may increase lag?
I hope my memory served me well when I wrote this down! I have now posted my dyno results - I wrote this from memory as I remembered my dyno man telling me over the phone... All will see how my memory served me.. I don't like to tell lies if I can help myself. I don't think I named these runs correctly on the attachments but open them and I have wrote the details of platform used there. I am not so good at using computers!
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I have attached dyno printouts for my breadbin as it has progressed, I have added notes on each as to the platform I have used, I have a drop-off and pick-up on the GT cam and inlet run due to wheelspin, not a flatspot.
I have wrongly named the attachments according to platform used but open them up and I have wrote on them what parts I have put in to get the results I have. Sorry for confusion..
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Plot with the GT inlet is very strange- peak 281lbft (also 247bhp)!!!
Did he get a clean run with this setup on? Be interesting to see the results for sure- decent amount of torque spread, would make it nice to drive on the road I think.
GT inlet vs. G40 - in terms of response due to inlet system filling, hardly anything compared to running a larger intercooler for instance.
Nice work ;D
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My dyno man will best explain any queries on the graph. Jonathan 07766224910. The torque figure he tells me is not correct due to wheelspin and the dyno trying to hold it back?? He reckons the horsepower is right but that the torque figure will be more like 250lb. The dip on the run was down to wheelspin and then gripping again. I will repost when I've done the bottom end and put the ATB diff in the gearbox, should get a better run for the torque figure then. I have g40 clocks fitted and it I have had it up to 145mph uphill with 2 pals in (on a track). I can't believe how quick it is, 3rd gear doesn't just overtake cars it jumps over them! I like it but the boost has found the bottom end's weaknesses. I am also shocked at how well it drives off boost, only a slight amount of lag and it's very predictable around town and it doesn't take much rpm to get it angry. It's worked really well, all these months of mulling around about roller bearing turbos/bigger turbos/hotter cams.. This has been an awesome compromise. I do need a 6th gear for sure or longer last 3 to see it's best. I was terrified at 145 as it was almost revved out, and will do easily I reckon 150 but was scared of it going pop in it's current state.. I do need to fettle its guts up before taking it above this!
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realy good results with plenty of torque well done you must be happy with this. What clutch you running? with that sort of torque the transmission must take a bit of a pounding. What do you mean when you say the boost has found telhe bottom ends weakness??
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I'm really pleased yes, and I believe in my my man's dyno too, he does a lot of custom builds and you get to see the before and after results on stock vehicles and it's close - actually reads many factory cars at less than manufacturer ratings. Well trusted round our way anyway. The bottom end's weaknesses - Just that it's obviously slightly worn as it's letting by on no3 piston (did leakage test) and it's blowing a lot of oil into my breather catch tank, I have vented the aux air valve to atmosphere to stop boost getting through this way, took block breather check valve out and vented both this breather and rocker breather into catch tank and it's blowing oil out the tank and into engine bay.. I am looking for a bottom end to build up to fix this, never showed any issues with G Lader but this amount of boost is finding any leaks.. Need to fix before I go any further, I think it will do more as the air temps are staying low and it's not showing any sign of flow issues and the K04-015 is holding boost all the way 'til it limits.. Just my injectors are almost maxed at 89% (350cc/3bar) but I've since discovered that no3 plug is rather white so I think I have a lean injector and the other 3 are making it smell right at the exhaust, didn't think 350's would be so high duty wise on such a small motor.. Going to try some of those Hong Kong £99 440cc specials next time hehe :D I'm a chinese junk fan! After all, these guys make a lot of stuff for the big names to put their stickers on.. I bought the G40 I broke up off a guy on here a couple of years back that had a well sorted platform (Leon Britton J350 RBR) and only know it has a fast road clutch of some description.. It seems to have all the bits he said it had.. 1341 etc. I had to laugh at the claimed 165bhp though.. I took it home - I think he sold it as he could never get it to run right - Got it on the dyno and it was 87bhp!! Had the wrong dizzy on that was 7deg retarded at max advance, ran cooking hot for obvious reasons, cooling fan was hard wired, thermostat was missing and he'd replaced every sensor. The dizzy would have fixed all of this. I quickly decided to run DTA managment etc, It has worked well for me..
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Plot with the GT inlet is very strange- peak 281lbft (also 247bhp)!!!
Did he get a clean run with this setup on? Be interesting to see the results for sure- decent amount of torque spread, would make it nice to drive on the road I think.
GT inlet vs. G40 - in terms of response due to inlet system filling, hardly anything compared to running a larger intercooler for instance.
Nice work ;
On my HZ cam run it was 172hp with the ported g40 manifold. The GT inlet allowed another 10hp with the same amount of boost = 182hp
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Nice to see the plots up here Dan, real nice chatting to you and I'm stoked the GT bits made such an impact.
Road-trip will have to be on the cards soon
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Do come up, you can take it for a run, I'll put some oil in for you!! It was an unexpected phenomenon to see it jump like it did. If you find that bottom end let me know (if you decide to sell it) Cheers :)
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Do come up, you can take it for a run, I'll put some oil in for you!! It was an unexpected phenomenon to see it jump like it did. If you find that bottom end let me know (if you decide to sell it) Cheers :)
Oh and thanks for selling me the bits, you helped speed things up for me.. Well done!
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Plot with the GT inlet is very strange- peak 281lbft (also 247bhp)!!!
Did he get a clean run with this setup on? Be interesting to see the results for sure- decent amount of torque spread, would make it nice to drive on the road I think.
GT inlet vs. G40 - in terms of response due to inlet system filling, hardly anything compared to running a larger intercooler for instance.
Nice work ;
On my HZ cam run it was 172hp with the ported g40 manifold. The GT inlet allowed another 10hp with the same amount of boost = 182hp
I used a Z20LET Vauxhall Astra Turbo intercooler with custom end tanks. It hides nicely in front of my alloy radiator. The car looks completely bgx standard outside, nice and sleepy
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Crackers results from this mate, get a build thread up so we can see the bredbin!
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If I can sum up the energy to do one in between work and their demands I shall have a go. I do have some pics of the car during various stages of rebuilding it but all I have of the mechanical side is a pic of it without an engine and then a pic with.. I didn't do the internet side of things, I thought I was the only one doing what I was doing and then I discovered this forum and became ill with Polos. If I'd have seen what people do on here I'd have taken more care with a pictorial :-\
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Bring it to the Pod ;D
http://www.polog40.co.uk/forum/index.php/topic,9940.0.html
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Dan you said you're running 250cc G60 injectors (dyno man had written 350cc), I've got a set of 315cc here (plenty of fuel for this spec) cleaned & serviced instead of some Chinese specials (Robin is the only Chinese special allowed)
Drop me a PM if they're of use- be cheaper than the eBay jobs too
Also just a note- if the torque figure is out, so is the power ;)
Get some fat boys out the local pub to stand on the front next time ;D
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I know that torque x RPM / 5252 gives you a figure of HP. My dyno man will explain the run better. He said the fact that dyno was fighting to hold it back at the start of the run due to wheelspin was causing a torque spike but where you see the dip is where it gripped fully and ran clean from thereon. The hp figure is accurate as it was not wheelspinning this far up the run. This man has been around for years in Cumbria, works about 16 hours a day and comes from a motorsport background (JDM Dyno). It was me that wrote the spec on the dyno runs for input to anyone that wanted to know what I used as a platform. My man said that the torque figure is more like 250hp at the spike point as he extrapolated the graph and could work out the trend. I can provide you with a versus time print out holding RPM to better explain this (a picture speaks a thousand words). I used 250cc G60 greens on the G Lader run and switched to Bosch Blue 0280150450 350's on the turbo runs so the 315's probably won't do as the 350's were at 89% duty cycle - surely the fact that these 350's were at 89% and lean burning tells you something about the power? I will happily stick the car on your dyno when I repair it for comparison purposes, this time round it will have an ATB in it so won't need fat guys - to be getting up to 150mph on g40 clocks up hills with 3x 85kg guys in it's got to be making some power. I wish it had 6 gears as it could easily pull another. :)
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I would love to bring it to 'The Pod' but I'm trying not to drive it with the bottom end as it has became (not an excuse to not prove it 'cause I'd eat humble pie if I had to) - it's developed horrendous blow by on no.3 and can I hell keep it in oil, catch tank full in 10 miles :(
It's probably going to take me a year to fix as while it's apart this time it's getting forged rods in it and the ATB + uprated shaft - something I'm going to have to save up for (unless anyone wants to take a deal on a PSD f/b charger, k03 turbo and whatever else I have for their ATB). It's still on the road ATM but local runs only when I feel like upsetting evo's up the bypass ;D
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My dyno man has looked through his files and has found good straight run without wheelspin, this one was from when we first switched from the HZ cam and G40 inlet to the GT cam and inlet and without touching boost or any of the map, it instantly went up to 220 hp (this was at 18psi same as HZ run). The latest result (the 247.5hp which I posted) was with a bit more boost and a tweak on the injectors which caused all the wheelspinning