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TURBO Q & A FORUM
Posted: 19 Oct 2003 15:12
I thought perhaps a few of us who know a little bit about turbos should debunk a few myths for people, if anyone is interested...
Hopefully Keith can pitch in answers too if he spots this...
So anyone who wants to post a question about anything related to turbos, post away... I will try my best to answer any questions...
Posted: 19 Oct 2003 15:26
1) Are there turbo exhaust manifolds available for L-series engines?
Posted: 19 Oct 2003 15:35
2) Can you make my turbo work?!and where do I get a waste gate?
Posted: 19 Oct 2003 16:01
3) EFI or Carburation?
Posted: 19 Oct 2003 16:27
No one I know of has made manifolds for L series motors for years...
I think Keith has an old 720 pickup manifold - factory cast iron log manifold - that he and Andy welded the flanges on to... Keith once told me he had scrounged the last manifold of that type in north america back in the day, so don't bother looking for one now, and the junkyard manifolds will all be too rusty to start with now...
My own L series manifold was made (and I'm guessing the same one that FiveOneOh has) by "Engine Air" in about 1972... that company became Dynamic Engineering, and they don't want to give you the time of day anymore... you'll have better luck with ADP Distributors
If you use reasonably thick mild steel for the flanges and the tubes, then ceramic coat it, it will work fine for most use. Stainless is really nice looking and makes for good bragging, but it is expensive, prone to cracking (people usually use really thin tubing for stainess headers) under the weight of the turbo, and makes no more or less power than a comparable non-stainless manifold...
You can get a wastegate anywhere, as long as you have some money for it...The Audi 5000 turbos had good wastegates, but most of the junkyards have been picked clean of them years ago, and there aren't too many of them around anymore...but keep your eyes open and you might get lucky
The Tial 35mm & 38mm units or Turbonetics Deltagate 1 or 2 and a few others share the mounting pattern of the old Rajay/AiResearch/Garrett wastegate that was so common in the days before Turbonetics and Tial... the tial unit is pretty nice, from the specs on paper, and it only ends up costing about $225US if you pick one up off e-bay.
years ago, I bought my garrett wastegate for $330 from West Coast Fuel Injection Turbo in Richmond - they were pretty good and honest people to deal with.
Fuel injection of you can afford it!
Carbs dispense fuel based on velocity through a venturi - if the density of the ambient air changes, the carb still meters the same amount of fuel based on venturi air velocity and mechanical orfice jetting; there is no mechanism that allows compensation for density change...
On fuel injection systems, you have a MAP (manifold air pressure) sensor and a MAT (manifold air temperature) sensor, which can compensate for the change in density created by the adiabatic compression losses of the external compressor ... if you set the wastegate to 10psi, and rev the motor from 3500 to 6500 rpm, the compressor efficiency will get better, then fall off (for most turbos, but that of course depends on the individual tirbo on the motor - thats another subject...) and when that happens, the temperature and density of the air being forced into the motor will be all over the place...
so yeah, if you can afford it, fuel injection is better...
...that's not to say you can;t get a carb to work - ask Keith if carbs & turbos can be made to work together or not...
When we first set up the fuel maps on gooned's race car, one of the other racers in the pits came over and commented that, "I've been racing for over 20 years, and consider myself pretty good at tuning motors with Webers, but in all the time I've been doing this, I've never got my exhaust pipe to look that clean! That's amazing!"... That took us about 1.5 hours of fiddling time in the pits and in practice sessions...
Posted: 19 Oct 2003 17:26
I pretty much agree with Rob, with todays technology, go with injection. It took me years to get the jetting / available boost / etc. to work with my carb. it is as fine tuned as it gets, but, as I saw with the big camshaft, I could not get it to run properly through that carb. If I was younger and had the inclination to tinker some more, I would have an SDS system on there in a blink with one of Byron's manifolds
I have a Delta Wastegate that has given years and years of reliable service. well worth the money. Make or get made by Specialty a good exhaust manifold. It has to go through an incredible heat range and lives a tough life.
Posted: 19 Oct 2003 19:15
Copied this from the other topic, posted by Rob F. (510rob):
I've been eyeing up two different units lately. A Garrett TO4E 50 trim compressor, or a Garrett T-61 compressor
The TO4E-50trim has an awesome wide range, and super high efficiency everywhere - I dunno why all of these honda kids are going with the 57 or 60, because they aren't as good as the 50 - actually I do know why - the 57 & 60 trim compressors were both available from the factory a few years ago as an OEM for something...other than that, I don't like either of them, and I'd recommend anyone with a turbo itch to get a TO4E 50 trim turbo...
A really strong start for a 1.8 to 2.2 would be a Garrett TO4E/T3 "ballistic" hybrid, with a 50 trim compressor with a T3 "stage 3" exhaust wheel (0.76 trim, 2.229" exducer diameter) in a 0.63 A/R turbine housing. For less lag, you could get a 0.48 A/R turbine housing, but you'd choke off the top end a bit. For better top end, and slightly worse "lag", or low end response, get the 0.82 A/R turbine housing. I have heard that in extreme cases, the 0.82 A/R turbine housing can drop enough backpressure that you can gain well over 50HP, but at the expense of a total loss of low end response below 4000rpm. The 50 trim compressor can do well over 350HP worth of airflow at about 22-25psi, still with very high efficiency, and wide range... that is awesome, and the 50 trim is a diamond amongst the other lumps of coal... put it this way people, if you are going to do a turbo without an intercooler, use this turbo... if you are going to run it with an intercooler, so much the better!!! The TO4E 50 trim is about the most I'd recommend for a part-time street car.
Now, if you really want to step up to the plate, the Garrett T-61 will tear your transmission in half nicely; its a very big kick-butt turbo... it has the capability to do 450-500 HP or more without straining itself, and it will really put the boots to everything around it! For a 1.8-2.2 motor, I would get a 0.70 A/R euro housing and a P-trim turbine wheel, but it won't come on 'til about 4500-5000 rpm, then WWWWOOOOOSSSSSHHHHH ...you will be thrusted into next week with top end you didn't think was humanly possible without Steve Austin bionics involved!!! The T-61 is a good high boost unit for a high rpm high boost race-track only car... almost a drag-only piece because of the P-trim turbine's big mass centroid...
For a good price benchmark, check out...
Posted: 20 Oct 2003 17:52
Are there any knock senors units for a L motor?
Posted: 20 Oct 2003 17:56
would a ihi turbo work on a L16
Posted: 20 Oct 2003 17:58
has any one tried water injection it works good on DSM and SUBURU at 12pounds what kind of whp numbers could you get from a L16
Posted: 20 Oct 2003 18:48
I built my own water/methonol injection system on my 510. It is self pressurizing so as to be dead reliable. I really do not think, if you keep the boost the same, that it changes horsepower that much. What it is meant for is an anti-detonant. Some "gurus" say it should not be used. Whatever. I feel that ANYTHING that you can do to keep the whole package cool, keeps everything happy and reliable. Bonus is it keeps the motors combustion area really clean. Ak Millar did lots if testing and found a 50/50 water/ methonol mix was best. I myself use straight methonol. My original turbo, on a stock 1600, at 12 lbs boost was rated about 120 hp.. Quarter mile times were in the 15 sec. range. That was a long time ago, 1972, but i think those figures are close.
Posted: 20 Oct 2003 19:05
Go there. Ask them questions - they always have a reliable answer.
They also have the entire kit needed for your L-Series motor, including turbo, manifold(S), and anything they don't have they can custom make it for you. They also do full-on restoration jobs for your motor.
If you plan to change anything in terms of compression, or just want some new pistons to match that new turbo, new valves, other stuff. They will have it. And if you're wondering where to get some new horsepower gains (20% - 50% sound good?) Paeco Industries can also make you a stroker kit for our little dime-motors. It's endless. All you have to have is money. (Stroker = $1299 US. Comes w/ pistons.) They also have titanium parts.
By the way, the Top End Performance (RaceTEP.com) specializes in our little dimes as well.
Posted: 21 Oct 2003 18:25
L-series motors did not come equipped with knock sensors, but odds are that most common knock sensors will work on an L-series, and if one particular one won't, then try a different model, or a different mounting position on the block! Knock sensors are selected by the car manufacturers to match the particular resonant frequency of a given motor's knocking characteristics, so different ones for different motors will have slightly different resonant tunings... as well, you should keep them away from the valvetrain, which has a lot of harmonic noise that could shake the sensor a lot and cause a bit of false triggering
IHI, Garrett, Holset, Schwitzer, 3K, AiResearch, Mitsubishi, whoever... they all make good turbos. As long as the compressor is matched to the motor's anticipated operating characteristics and output range, and the turbine is matched to give adequate energy to the compressor without causing excessive backpressure, it doesn't matter who made the turbo... Greddy turbos are IHI units, and HKS turbos are Garrett units...
The use of water injection came about hand in hand with the development of nitrous oxide, and it had NOTHING to do with automobiles, and EVERYTHING to do with dive bombing and dogfighting in WW2... if you dive bomb, you want to rip down to the target, drop your bomb payload, and then get the hell out of there as fast as you possibly can, or faster if possible; you'd want as much power to climb as the motor maufacturers could give you. The developers came up with two distinctly different methods of extending the power output of large aero engines; water/alcohol injection and nitrous oxide injection; you either run waaaay more intake pressure with water/alcohol injection, or standard intake manifold pressure with nitrous oxide!!!
If you want to read a ground-breaking academic work about water/methanol injection and nitrous oxide, look for a copy of H. Ricardo's "The High Speed Internal Combustion Engine". It has extremely thorough labratory research documenting the use of water, methanol, and water/methanol injection as an anti-detonants, and nitrous oxide as a power enhancer. Mr. Ricardo did aero engine development work for the British war effort between WW1 and WW2; they took their work VERY seriously - when they did that research, it was to win a very bloody war, not a street race against a Honda!!! ok, enough, its a really good book - buy it, read it, learn it, live it.
As Keith said, some people say not to use it, but most of that is because it is a system that must be replenished, and if it runs out, your going to fry the motor so fast, you won't know what happened until its too late.
It helps to stabilize combustion past the detonation threshold for a particular fuel, so you have to actually exceed the detonation threshold to make any gainful use of it; you can crank up the boost past the normal limit for the fuel, and you won't fry the ring lands, crowns and bearings...
Keith runs very high static compression for a turbo motor, and his very ingenious methanol (anti-detonant) injection system is a major factor in his motor's stability and the long term reliability of his motor... Keith, how many years did you get out of the last motor between tear-downs?
(Keith, I kinda think you should tip some Nitromethane into the alky tank one day, "just to see what would happen..."
Posted: 21 Oct 2003 19:09
good lord you two know your stuff!
Thanks very much for taking the time to answer all of our questions!
Posted: 21 Oct 2003 19:38
Hi Rob, the last motor was 13 years old!!! It slalomed for most of those years, did thirten years of Knox Mnt., ran Westwood on our track days, and I used to get to play with Specialty Engineering on their test days at Westwood, ran events in Seattle, did all the street races...and most of the Mission track days. Plus the road trips and cannonballs. Whew! I did not count the last few years because it was never driven very hard. The pistons were in mint shape..and are for sale. The stock rods survived all those years, and had seen 8,000 RPM many times. Mostly I shifted at 7,200 RPM. The crank was just starting to crack on #4 journal, and the block had a small crack at one of the head bolts. Bottom line, keep them cool, give'm good oil, do not let them detonate and love them to death!
I should have said, never use water injection as a crutch! All things should run within whatever parameters ones engine package dictates, then, water injection and other tricks just add to the reliabilty factor. I really stuck to the 16 lbs max rule I imposed on myself. All jetting and exhaust temps where well within safe limits at this level. That let me go wide-open throttle to 7,200 RPM in 5th gear, lap after lap, mile after mile (Cannonballs!) and all was happy. For thirteen years. Now I have Crower Rods in my new motor and may actually sneak up on a bit more boost, on race gas of course, and see what temps/ mixture is doing. Should be an absolutely ballistic experience. With this camshaft in now, it was fighting for traction just rowing it through the gearbox, at 14 lbs boost.
Thinking a lot over the last few days, with all the turbo, I still would vote for turbos over all other performance types. What you get is incredible FLEXIBILITY!! Why, because you can actually turn the power up or down. I can turn my boost down to the default setting on the wastegate ( 10 lbs) or UP to full kill mode (16LBS) This has proven invaluable to adjust the car for a given slalom course, or road course, or weather conditions. On tight slaloms I would turn the boost down, just to the point of traction available. I won most of my slaloms at 10 LBS.! Also, with a little gee-whiz gadgetry, as some of you know, that little tank in the trunk carries the 116 octane race gas for full kill mode. Turn that knob up beside you ..and ...WHAMO...power to spare. How fast would you like to go up the Coqahalla, 120 MPH, no problem sir, coming right up . HA! And I get 22-25 MPG. I have seen Jasons car and it is the same, just effortless power, and torque. Anyhow, I have rambeled on enough here on the turbo thing. Go for it.
Rob, would you give me a call at home or work when you get a minute Work: 604-270-8778 home 36-6062