Finally the time has come.. I have enough money to do a build thats been been in the pipeline for years.. Decided back then that if I didn't have the cash to do it right, I wouldn't do it till I did..
Not wanting to waste money, I need advice from guys that are wiser and more experienced in turbo conversions than what I am.. So pretty much what you guys say will work well, will get done..
I'll admit i've gotten real excited this week and have already bought a turbo and intercooler (hope I haven't wasted money already).. I also have an exhaust manifold that has been laying in my garage for about four years waiting for this day, so the poor thing will also have to be used.. Ill Post up pics of what I have so far (not much but its a start)
My aim for the car is for it to do an 11-11,5 second quarter mile pass, turn it around and drive it back home.. Car will be driven on the road very often thus im not really prepared to have stripped out interiors and roll cages just yet..
Ive read heaps of threads regarding 16v turbo builds, but what makes mine a litle different is that I want to intergrate ITB into a custom designed carbon fibre tapered plenum.. ITB wont increase power but will improve the responsiveness of the car and plus it has space for eight injectors..SWEET.....
What I have
Garrett 2876r ball bearing turbo
VW Golf V TDI intercooler
Trusty exhaust manifold (Tubular)
40mm Individual throttle bodies
What im thinking of getting (ADVICE NEEDED HERE)
Forged pistons (Wiseco) compression ratio 9,0:1
Gotech Pro X ECU (http://www.gotech.co.za/productprox.html)
Hi rev set up on head: Stainless steel valves, hi rev springs, high duration turbo cams
CATCAM: (Part #7641319) 284 / 257° (they say its suitable for turbo applications but i'm not quite sure)
Quaife limited slip diff
Semi slick tyres
Thought by raising the rev to around 9000rpm, it should get me into the sweet spot of the turbo running at 1,5 bar (22 psi). but if i need to boost more let me know..The idea for increasing rpm came from a write up in the following link
Please guys i'm sure i've missed out a bit of stuff that I need but thats where I need advice. All the parts im thinking of getting might be wrong, but please steer me in the right direction.
Starting the build in four days time
Okay, first, power does not equal lower times, grip, especially in a fwd car is everything! The quickest fwd mk2 here is a 20vt with a little IHI VF34 turbo (just over 400whp with nos). Does quarter in 10.5 seconds at 135mph and has only forged rods as engine mods: http://www.eurosportscompact.co.uk/e...il.php?escID=1
2876 is not really preferred by most as it is a bit mismatched, compressor is large and turbine small, you could have some surge issues, bad lag etc will just have to see. The 2871 or 3071 .63 would be better but stick with what you've got for now. It'll do email@example.com bar so enough there for your times.
You want to be able to use your car daily you've said so I would first look at strengthening the engine. By having it overbored and fitting forged rods and pistons the bottom end will be solid plus you'll gain a little more displacement which helps with spool. Revs will also help but just a set of HD springs will help stop valve float and VW engines are best tuned for torque (7-7.5krpm should be plenty) compared with other engines i've modded like Jap cars.
DEFO get an ATB diff and sticky rubber, light weight parts that you can (p.s. James Hodson that runs tens swaps to solid rear suspension and slicks on track, takes them off after and drives home).
Intercooler looks pretty big, plastic end tanks but see what it's like when it's up and running, aim for under 40 degC charge air temps, make sure no bodywork blocks direct air currents etc, same with induction.
At that boost 9.0:1 should be okay, 8.5:1 may be a bit safer & allow you to pull more timing, run higher boost. I'd personally use a single throttle body and tapered plenum design to ensure an even distribution of air but that's just me, it's also cheaper! With the boost/turbo you've chosen peak torque is going to be shifted pretty high up the rev range so you'll likely have to sacrifice a bit of bottom end when you Helmholtz frequency your specific set-up. Short runners and large plenum volume best then. Save using twin fuel pumps and 8 injectors, twin rails etc, modern 850cc ID's and the like are plenty good enough when tuning if your EMS is good (and don't skimp on EMS/fuelling).
If I was doing it I would get a 2871 .64, +1mm overbore and forged pistons and rods, perhaps add a 95.5mm diesel crank, HD valve springs and port polish the head. I'd TIG up a metal intake mani then concentrate on the clutch, add intercooler spray, water meth etc, get the charge air temps down and concentrate on grip.
What you've got is a good start, people drive differently, prefer revs etc, but the head would be the last thing on my mind as you don't need pairy cams or silly power for those times in a mk2 Golf! Hope this helps?
only thing i got for ya, is that if you run quicker than 11.500 you will need to put at least a 5 pt roll bar with driver side door to meet NHRA compliance. with this roll BAR you can legally run down to 10.000 as long as you do not go quicker than 135 mph.
so aim for 11.55 or so if you want to keep it with out a roll bar.
and that little 2876r will be WAY PAST its efficiency range @ 9k rpm.
Id love to use the diesel crank but ive heard some stories of guys pulling their hair out because of their protrusion heights.. Do you guys think its worth the headache and which companies would be best suited to source the rods and pistons.
I've taken a real liking to wiseco pistons (please dont ask why because I really dont know ;-)), but when it comes to rods, does brand matter. Arais, Pauter, K1 to mention a few. Which is best on an application like mine.
As for the turbo I had no idea that the turbine side would be small. Im actually bummed hey. their is tons of info on sizing the compressor (and I almost got it right), but sizing the turbine, does anyone have links, or could anyone give further insight. I know it was suggested that a GT3071 would of been a better option than the GT2876. Ive just looked at the compressor maps, would the GTX3071r be better than all of the above or am I wrong again.
Also been thinking of splashing out on Supertech goodies for my head. They have a comprehensive range, but the question is, is the price that one pays for it worth it.. I mean black nitride valves going for $24 each.. Also love the spring kit and titanium retainers they offer and thinking of getting them.. What do you guys think. good option or bad option.
Taking out engine today and going to start cleaning out the stuff I dont need in the engine bay.
And I know their are tons of questions that ive asked, and I appreciate any help I can get..
This is a little off topic, but I'd like to give some advice about something that I experienced with my turbo build. Weld the studs into the turbo manifold, and then use Stage 8 nuts to secure the turbo. That way you won't have to worry about the turbo coming off the manifold. You can get the nuts on Amazon, or at stage8.com. Good luck with your build.
Ok given it some real thought and I think I might go back and see if my turbo guy will exchange my turbo for me. guys running 11sec quarter mile have around 450hp+ at their disposal. (yes their could be exceptions, but hear me out). To get that power is easy, just slap on a monster turbo and away we go.
My concern is the drivability aspect and it all comes down to choosing the right compressor to turbine size to give a mix of power and less lag. which turbo would give the best performance for the least lag. So a compromise. And at what revs would I get full boost? (spent hours researching that last question).
Garrett GT 3076R
Garrett GT 3582R
ALL ABOVE WITH 0,63 A/R TURBINE SECTION.
Going to press buy tomorrow on supertech valve springs&retainers as well as intake and exhaust valves... All opposed speak now ;-).lol.
SPRINGS AND RETAINERS
Spent some time trying gain a deeper understanding of compressor maps. Playing around with some numbers and plotting them on the relevant compressor maps for the turbos I mentions earlier.
Now lets see if I got this right. If you have a turbo big enough, lets say a GT3076r, 450hp is achievable when running at 29psi.
I plotted two points representing the corrected airflow at 3500rpm and 8500rpm at a pressure ratio of 3 (29psi). The point representing 3500rpm lies to the left of the compressor map. This means we not at full boost right?
Now if we do the same plot but this time using a pressure ratio of 2 (15psi), we should be getting the full 15psi at 3500rpm because that point lies inside the compressor map with an efficiency of around 70%.
Am I correct???
92 Corrado OBD2 ABA Powered by MS3Pro
M & L EFI Performance
witsveg, pls tell me where are these velocity stacks from? Any link?
BTW here is a good place to start:
Last edited by vr-vagman; 04-14-2012 at 02:02 PM.
Velocity stacks are from Precision Race Technologies (http://www.precisionrace.co.za/content/precision.html)
Doubt they will export out and their website is quite poor in any case. Jenvey sells the exact same velocity stacks from the UK. They have a wider variety and they cater for worldwide shipment.
Fuel Injection Throttle Bodies and Induction Systems from Jenvey ...(www.jenvey.co.uk/)
Dry sump it is.. Will be money well spent. Don't want to spend money and have pieces of engine trying to kill me when they decide that they don't want to stay in the engine.
Any input on the turbo selection up above. And do we get better response out of a turbo (less lag) if we run lower boost??
There is no reason in heck you have to run anywhere near 9,000 rpm for any of those turbos to have a great power band, unless something else is very, very wrong.
Also we have ran the 2.0 16v to 8500-8800 rpm for an entire race season, with datalogs of the oil pressure and no issues.
Putting a dry sump on a drag motor with these modest goals is ridiculous.
If you do not want to waste a pile of money, and still not reach your goals, give me a shout.
Last edited by lugnuts; 04-16-2012 at 11:16 AM.
Eurodyne Maestro Tuning, Stand-Alone ECU Install/Tuning/Wiring Harnesses