Turbos

[joedude]

Ranger... Man. Try to ignore all those nay-sayers and go forward with your creation! Don't forget to post what you figure out.

I have a few tuners at work... they've turboed Jetta's and other vehicles of the type and they want to help me out this winter to rejet my GS. I'm really looking forward to it and so are they. Every little bit of info you provide would be greatly helpful!

I was thinking of doing a suck thru carb turbo setup with a wastegate instead of a BOV for simplicity and easy of jetting (I guess).
any suggestions?

[saxman]

no no no no no


draw through carb set ups? NO!


if you want it to last, go blow through. To quote the great Corky Bell, "Blow-through statrs better, idles betters, runs smoother at low speed, and produces quicker throttle response and lower emissions. An intercooler can only be used with a blow-through application. The draw-through system is a dead fish."

If you want to know the best way to set the carb up, pick up his book... "Maximum Boost"... chapter 8 discusses carburetion and how to modify normal carbs to work

[rangerbrown]

buying tha book, now.

i would love to go EFI but man that mega squirt is beyond me. i could easly spend 800-900$ on that

jets are cheap.

[saxman]

buying tha book, now.

i would love to go EFI but man that mega squirt is beyond me. i could easly spend 800-900$ on that

jets are cheap.

blow through carb set ups work great... yah, you don't get the same tuning capabilities of efi, but there's no reason a good blow through carb set up can't be used with good success


ranger, if there's anything I can do to be of assistance, let me know. My knowledge of turbos and such goes much much much further than my knowedlge of gs's(which is really pretty limited) though

[rangerbrown]

dont worry, by that time i am done your post count will be up around 200-400

[saxman]

dont worry, by that time i am done your post count will be up around 200-400

I'm not that new around here... just don't post often


"Date Registered:  August 04, 2003, 05:20:53 PM "

or so says my profile

[ignoreance]

I have done the numbers and cacluations before  get ready for custom pistons to drop the compression about 4 points and you need to run about 22 pounds of boost cus  the turbo isn't going to spool...  but have fun with it.... Trust me I have enough problems with My 39mm CR special carbs not moving enough air tell about 6,000rpm   going to put a turbo on it look out for the surge... you are going to have no bottem end to do it right I don't care how getto you go and how many used 2 dollar whores you have your going to need about 4 grand to do it close to right and about 6 to really make it fun bags up...  No problem oh and you need to cut your cams sprockets so you can change the cam overlap.....  make sure you buy another bike before you play cus it sucks not getting your twisty fix....  I was always slappin my arm jones'n  while I had my bike apart. But then again maybe you have some good knowledge I don't and a little more experieance than i I do...  Maybe if you wanted you could talk to Bob B. if he is still on here and he could give you some info but then again he never went for turbo.  The problem is displacement on our motors to ge a turbo small enough to start boosting in the right range. everything made for cars is to big. Got to remember we are half a Gsxr1000 the put one of the smallest T3 turbos on those and make them go nuts and start building boost they run like 8-12 pounds. our engine isn't moving enough volume to start pushing the turbo. oh and at the volume that it will start pushing from the engine your goin to be breaking parts.. cus our engine isn't made to put out 110hp where a turbo will start the boost range...  I have poored over this Idea time an time again I know its the GS500 Cool factor but if you want a money pit like my bike has been and have 10k of stuff on a 2k dollar bike  so be it keep me posted. I will check back in a year.

[saxman]

I don't know why anyone would run a t3 on a gs... it's WAY too big.

With something more like a gt12, you wouldn't have any issues spooling.



ignoreance... a lot of your post makes me really wonder about your grasp of a lot of the concepts of a turbo set up. I could just be misreading what you're saying, but some of the stuff doesn't add up... lowering the compressior 4 points? With a 9.0:1 comp ratio, there's absolutely no reason to mess with the comp ratio. Drop the comp down to 5:1 like you're saying, and you're absolutely right... it'll be a huge pig down low and never spool, but there's absolutely no reason to do so. Also, the psi made by the turbo isn't really limited by the motor... a t3 doesn't make 8-12 psi because it's on a gsxr1000... it makes 8-12 psi because that's what the wastegate is set at.


and you're right, the motor isn't made to put out 110hp, and I doubt that ranger is really looking at making that much power, but you have to keep in mind that less power, reved out to a higher rpm puts significantly more stress on the internal components then more power down low. Also, a 50-75% increase in power really wouldn't be that difficult, and would make a huge improvement in the perofrmance of the vehicle.

[CirclesCenter]

Ignoreance, it sounds much like you ended up crossing the surge line with your turbo. (Meaning the turbo you have is to big)

5.0 to 1 compression? Ummmmm............. I don't know where to start.

And to assure you that they come in small enough sizes for the GS.....


Here's that turbo mounted on a 120cc scooter. Supposedly works out pretty well. (Nm he sprung an oil leak, but can hardly blame the turbo except for faulty construction.)


I can't pull up a compressor map for that little jobbie, but if I could find it I'm sure that the map would be too small for the GS to fit on.

I think your understanding of how a turbo produces boost is flawed. Horsepower has absolutely nothing to do with with a turbo spooling and creating boost.

You're on the right track when you're talking about volume. All that is needed is a turbo that produces the correct flow at the correct pressure from the GS's exhaust flow and pressure. (Finding the right one is the tricky bit.) Going too small is actually a LOT better than going too big.

Anyways, time for me to sleep and wonder.... WTF did I not just let this thread die?

[ignoreance]

I have already pulled my compression up 3 points..... Sorry and a need for the clarification and on most of the newer bikes your pullin them down 4 points... a stock 600-1000 is running mostly high 11 to 13. Most of the ex400 honda kits out there are around 4k so yeah you can buy parts from those kits I.E GT12 but why why why I know how much i have done to my engine and know what works and what doesn't  yes your correct in saying a GT12 will work after paying to get it the trim right and exhaust tubes set up.  Spend the money have heat issues pay for aftermarket coolers. make sure you get a newer GS motor.  But then again I think you have one..... Cus your going to have to tap the oil pump in another way if your working on the older GS motors which I have worked on   its a pain to tap in. If I had known all the headacke that I was going to have and all the money I have pumped into my bike and believe me I know how to throw time and money into things. Also timing can be an issue but these guys are willing to help.... Me I'm done slamming my head in a wall just getting my NA to run right.  I know what your saying about the wastegate but what I'm implying is there pretty much stressing the engine at 8-12 pounds of boost.  I under stand it all works on Volume its getting the boost in the target RPM to match up and the displacement  of the engine thats the key... (map) setting the right trims in the turbo I know how things work and have played with a many air cooled turbo corvair engines. A bike isn't like a car where the boost range is 3000rpm window. its got a wider range which has its plus and negs.. why I'm explaining myself I don't know...   Blah now I'm tired and maybe thats the reason why I'm babling on and on yes stock is 9 to 1 and in a perfect world dynamic compression and static compression would be the same all the time but there not so goodnight.

[LimaXray]

i would love to go EFI but man that mega squirt is beyond me. i could easly spend 800-900$ on that

it wouldn't cost you nearly that much to do it...  a full standalone engine management setup (and I mean FULL setup) with both efi and ignition would cost you around $300... I've done a lot of work with Megasquirt and would be glad to help you with it, including building the kit and setting it up for ignition for you if you did decide to go that route.

carbs might be easier, most likely cheaper, so either way is cool

As for turbo size and what not, a GT12 looks like it would work great, maybe even a little on the small side.  Unless you have a high end machine shop and you can machine your own turbine and compressor wheels, 'getting the trim right' is as easy as looking at the efficiency maps of the few available trims, doing a little math, and picking which is best for you.  To the best of my knowledge there is only 1 trim for the GT12, so that would be a pretty easy selection.  A 40 trim T3 or 45 trim T25 would *work* on the GS and are pretty cheap because they are fairly common on economy turbo'd cars, but you would be out of the compressor efficiency range through most of the power band making it really kinda crappy so it may not be worth the saved $$$. 

As for oil supply, that's not a problem.  New or old GS I'd just use the oil presure port for oil supply and drill a hole in the oil pan for the oil return.

[saxman]

a gt15 could make for a very interesting turbo... probably provide a little more wiggle room than the gt12, but I don't know the points off the top of my head for a gs motor


as would a vnt18, but that's a whole other discussion... has so many benefits, but a bit more fun to set up.


personally, I would try to go efi if I could, if anything, for the ease of ignition control. On a turbo motor, ignition control is extremeley important to making the thing last. If you go efi, I bet you could find a way to make some itb's from a cbr motor work... yah, it's for a 4 cyl, but they come in sections of two, and could easily be split in half. Already has the spot for fuel injectors and everything.

[rangerbrown]

i am thinking that the GT-12 will be better.

will supply what i need with out a lot of problems from lag

[ignoreance]

The oil pressure port.... hahaha....  Yeah its called reduced oil flow to the cylinder heads Take a look at your trusty shop manual from the dealership and and look at good old pg 4-14 you tap that bad daddy and you watch your main gallery pressure go to shaZam! cooking the majority of your bike...  have fun with that. The new engines are tapped after the oil filter and before the main gallery  so its filter then cooled before sent to the main gallery then on to the top of the head crankshaft and most of the other engine parts...   If it was really that easy don't you think there would be a write up about it..... Der de Der. I have had the motor apart a couple of times......  Its just that easy to tap things bro make a kit. sell it  and give us all an option for the old engines.... but I guess if your goal is to run an oil pump instead of a bike go for it. If you got something that proves me wrong on that then show it. Cus I will be the first to admit I'm wrong. 

oh and im with saxman I like the GT15 better it will come on smoother and be a little more scalable.


Sorry if i didn't cook the beans long enough last night. I tend to type and then not edit so sometimes it doesn't make a complete idea.

[rangerbrown]

i was thinking about a complety seprate oil res and pump system, (space depending) or jsut up the press on the regulator.

[saxman]

keep an eye out for a small aerodyne aerocharger... perhaps from the mazda miata kit that was sold for a while...


would be a very lucky find, but would completely solve your oiling needs, and those vnt turbos are just plain sexy

[LimaXray]

You really think tapping in the oil pressure port would cause a significant loss of oil to the head?  I really don't know, I was figuring it would be fine.  I realize you couldn't put an oil cooler here, but I wasn't talking about an oil cooler, I was talking about a turbo. You would need a restrictor on the oil supply line to the turbo, something like a 0.06" restriction.  I don't think that would divert THAT much oil. 

an Aerocharger would be cool, but other than in maximum boost (which kinda pissed me off because they managed to avoid showing you examples of oil/coolant connections), I have never seen one.

as for VNT, that would be pretty niffty, but do they make them small enough?  They are pretty complex machines and I've only heard of them on diesel trucks.  I could be wrong, I really don't know much about them, but a properly sized VNT turbo on the GS would be retarded (as in the good kind of retarded)

I personally would go with a GT15 as well for a number of reasons. 
1) the lag difference between the GT12 and the GT15 would be minimal because of the already high powerband of the GS
2) neither should suffer from any significant surging
3) the GT12 starts to run outside of the efficiency map towards the top of the powerband, maybe not a problem with only 80hp, but after that you'll run out of steam
4) they are the same price
5) the GT12 uses god-knows-what flanges, I have no idea where you'd get those flanges, whereas I believe the GT15 uses standard T3 flanges that can be found at any speed shop or online turbo store/eBay

one question though, is the GT12/GT15 water cooled?  might be a little tricky, but I know someone has used the GT15 here before, so I dunno...

[sledge]

PHEW.....Judging by all the talk this Turbo Mod is really gonna be something when its completed. Why not give the Discovery Channel people a call, they might interested in doing a series about it.  When are we gonna quit talking about it and actually start rattling the spanners???

[rangerbrown]

as soon as my loan goes though for my new truck, theres some extra dow in the deal

[saxman]

with the aerochargers, there aren't water/oil connections... that's how they avoided showing them, and what makes things so nifty for this use


vnt turbos are available in a huge variety of sizes... you could probably find something like a vnt12 of a small european car, etc
they came on all sorts of cars, diesel and gas alike.

what flange the gt15 runs, I have no idea... I'm sure atpturbo could hook you up with them.

don't stress about if the gt15 or gt12 turbos are watercooled... there's no reason you can just plug said ports on the turbo and run it oil cooled only. Would require some good synthetic oil(which you should be running with a turbo set up anyway), and proper cool down of the turbo before shutting the bike off... but absolutely no reason it can't be done.


and sledge... they key to a well executed turbo set up is lots and lots and lots of planning. Get everything figured out before a dime is spent. Rushing into things is going to do nothing be jeapordize the set up.