Is there a way to get boost at any lower rpm than 5500.
Tanks Charles Johnson, P.O. Box 30577 Midland TX> 79712
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low rpm turbo boost
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 seca650turbo1536 |
low rpm turbo boost |
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Posts: 19 (08/29/06 18:35:53) Participant |
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PositivePressure |
Re: low rpm turbo boost | ||
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Posts: 459 (09/03/06 11:46:09) Wannabe |
Use an 04 impeller instead of an 03. There was a thread on this with pictures.
Michael Oberle -'82 Seca Turbo
May The Boost be with you. http://plan9.dnsalias.org:88/xj |
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turbo bob |
Re: low rpm turbo boost | ||
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Posts: 375 (09/03/06 18:36:17) Wannabe |
qhy bother ,this way its like a big governor,which lets me get over 50 mpg all the time since its only turning 4400rpm@60mph,..........anyway thats what they make a manual trans for ,so you can be in a lower gear and have boost right now w/o lag,alot easeier than anything else
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PositivePressure |
Re: low rpm turbo boost | ||
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Posts: 459 (09/08/06 17:33:09) Wannabe |
True but I too would like the power to roll on earlier. A BOV or waste gate can deal with the excess.
Michael Oberle -'82 Seca Turbo
May The Boost be with you. http://plan9.dnsalias.org:88/xj |
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seca650turbo1536 |
Re: low rpm turbo boost | ||
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Posts: 19 (09/10/06 08:32:27) Participant |
If the boost kicked in at about 3000rpm launch of the line would be alot better for a quicker et. And some times you just need the boost at low rpms
Tanks Charles Johnson, P.O. Box 30577 Midland TX> 79712
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turboj544 |
Re: low rpm turbo boost | ||
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Posts: 291 (09/10/06 10:05:46) Road Warrior |
port the hump in exhaust port.
i did mine it works |
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Daviddurtschi |
what? | ||
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Posts: 6 (07/07/09 13:06:29) |
What does "port the hump in exhaust port" mean? I would like to get a lower rpm boost but don't think I'm capable of doing the machine work
to go from 03 to 04 (what ever that means).
Thanks for any enlightenment |
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MrXJ650LJ |
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Posts: 120 (07/07/09 21:02:21) Weekend Rider |
There is a small hump in the casting off the cylinder head inside the exhaust port, it has some burs on it, removing them and making things smooth makes for
better flow........The 03 to 04 compressor upgrade is a bit time consuming and costs a little $$, i'd be more inclined to de-activate the wastegate and put
effort into upgrading the brakes and suspension. -Nick
Nick Shanks
82' Seca turbo (almost stock) 83' Seca turbo (highly modified) 83' Seca 900 to 650 Turbo (project) |
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900Turbo |
Boost | ||
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Posts: 1 (07/08/09 00:34:26) |
I currently run various versions of 4cyl and V8 turbo cars now and have built turbo bikes over the past 20yrs. Everyone here seems to be afraid of being
innovative outside of the the T04 turbo swap.Yes, hog out the exhaust side ports but what good is that going to do if the collectors are still restricting the
potential. I used a SECA 550 single collector exhaust and bent it to fit the 650 Turbo motor (Didn't take much!) then welded on the T25/28 flange and used
a T25 from a SAAB 9000. NO THIS IS NOT A DIRECT SWAP!!!!! You need some fabrication skills, such as welding, plumbing the lines and a general eye for making it
work. It is very doable and cheap! Low end boost was AWESOME! It kicked in around 34-3700 rpm and power was much stronger through rpm range. This setup on a
900 will yield even more potential, even with the boost turned down. If you can get 900 valves and run them in a 650 head with a 700n cam (-3degrees, so I have
seen on this sight), this should yield even more power potential. These motors will yield some excellent numbers when built and tuned right. Just me and my
experience!
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MrXJ650LJ |
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Posts: 123 (07/09/09 21:08:08) Weekend Rider |
Do you have any pictures?? That does sound interesting.....did the turbo still mount in the original location in front of the rear wheel? I have a tired 900
motor sitting in the corner and have often thought about doing the top-end swap, but don't want to spend the money on rings (exspensive!)
Nick Shanks
82' Seca turbo (almost stock) 83' Seca turbo (highly modified) 83' Seca 900 to 650 Turbo (project) |
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900Turbo |
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Posts: 2 (07/16/09 23:02:24) |
I have taken the exhaust off for powder coating. As soon as she is back from the shop I will install and take some pics. Yes the turbo mounts very close to the
same location and lines up quite nicely. I am looking at installing a Ford Probe Intercooler. It is small and has enter/exit on same end so ducting should be
pretty easy. I also took the bypass/bov and will install it too. Bare with me!
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maximturbo |
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Posts: 1 (07/22/09 09:27:53) |
Hello 900Turbo,
I am uncertain how mounting a much bigger turbocharger (the t25 is bigger than the tco3 and tc04) will provide for lower boost response. I would have imagined that it would increase the onset of boost, not lower it. Can you explain this to me. also, were these boost onset figures of 3000-3500 rpm noticed on a stock 650 seca motor I dont see the difference in the seca 550 collector. I was going to put the turbo 650 motor in my 81 650 maxim and have the turbo mounted up front directly below the exhaust ports with a custom exhaust turbo manifold. This should increase boost reponse also, as the turbo is much closer to the exhaust ports. thanks. also please provide pictures when available. |
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900Turbo |
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Posts: 3 (07/24/09 17:20:33) |
I did this set up because it was what I had available and said why not. The exhaust system just doesn't breath efficiently. Has anyone really looked at the
size of the pipe going into the flat collector? SUPER RESTRICTIVE! Before anyone screams back pressure, the turbo creates enough back pressure to run just
fine.
The SECA 550 header has larger inner diameter pipes, but not much larger than the stock ones, just enough. The header collector is about 2" in diameter. This means far less restriction going to the turbo than the stock flat collector and 1" port to the tiny turbo. Yes, the hot side on the T25 is bigger than tD04, but so is the compressor side. With the addition of the less restrictive header and collector, the turbo takes a bigger hit of exhaust to spin the hot side. The compressor being bigger brings on boost much faster than the tiny stock turbos they came with, plus the downpipe/up pipe is larger than the tiny stock pipe, again enables faster spool up time due to less restriction. Its essentially the same basic idea we use on turbo cars. An equal length tube header into a decent sized turbo with a bigger compressor wheel. (i.e. T3/T4 hybrid turbo mounted on a center collector tube header with a large downpipe makes dramatic increases in response on turbos.) Yes, the turbo mounted right in front of the bike is going to get much better response than the long tube will. Were you going to mount the tiny little turbo upfront? Probably not. The t25 is not much bigger than the turbos used on the GPZ 750. I feel this was a very worthwhile setup, looks stock to most people not in the know and CHEAP! I could have went with the front mount setup, but I didn't want to cut up a perfectly good header. Oh yeah, the t25 is oil/water cooled, so an external radiator (Use a trans cooler or whatever, I used the SAAB stuff) and a small electric fuel pump was easy enough to wire in. I am looking at routing the radiator under the seat, may keep it upfront not sure yet? Then adding a Ford Probe intercooler, manual boost controller, bpv and piping, plus removing the surge box for a copper pipe intake log to facilitate the install of the intercooler piping. I'm thinking about 20 psi boost? Just curious? |
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maximturbo |
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Posts: 2 (07/28/09 09:37:38) |
interesting. can you post pictures of your rad setup?
having the turbo mounted upfront should help even more. what boost level are you running? what is the stock wastegate pressure on the saab turbo wastegate? also, did you need to do any jetting changes (as there will be more flow at the same psi level).? so 3000-3700 it begins boosting, even on the stock 650 motor? if so, thats gonna be one killer setp. any compressor surge? |
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900Turbo |
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Posts: 4 (07/28/09 21:37:01) |
The stock surge box blows at 15psi. The Wastegate on the T25 is disconnected at this point. I have it routed like the stock system right now. I am looking to
use the Probe stuff and log intake here soon while the bike is apart. Should keep the bike boosted to 20psi when done. I haven't changed any jets yet.
Seems to run pretty well as is.
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maximturbo |
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Posts: 3 (07/29/09 09:22:07) |
well ive purchased a 9000 turbo off ebay. next step this winter is to pull the maxim 650 motor and slap in the 650 turbo.
doesn anyone have a wiring diagram for the 650 turbo seca? i need merge the two wiring harnesses, probably the hardest part of the swap. also, can anyone tell me how is the fuel pump on the 650 seca powered? is it running anytime the key is on, or only when motor is on? does it run off the headlight relay or operate similar to the headlight? |
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maximturbo |
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Posts: 4 (08/14/09 09:36:56) |
any luck on photos?
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maximturbo |
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Posts: 7 (11/05/09 10:11:47) |
any updates?
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PositivePressure |
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Posts: 455 (11/05/09 17:57:09) Wannabe |
900Turbo wrote: Just block the poppet valve in the stock surge tank. The surge tank will give better flow than a log intake.
Michael Oberle - Looking for another project
May The Boost be with you. http://ootfab.webhop.net/xj |
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PositivePressure |
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Posts: 456 (11/05/09 18:01:29) Wannabe |
900Turbo wrote:Well, that all sounds interesting. The shape of the collector does three things: 1) Ground clearance 2) Scavenging 3) Increase gas velocity with only minor increase in back pressure
Michael Oberle - Looking for another project
May The Boost be with you. http://ootfab.webhop.net/xj |
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PositivePressure |
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Posts: 457 (11/05/09 18:24:02) Wannabe |
Has anyone actually looked at the specs on the turbochargers you are talking about mounting? Seriously.
The units being discussed here do not have an available trim level suitable for a 650cc engine. These units are sized for engines about 1.6l (that is 1600cc) and up. The charts are out there. Have a look. A bigger turbo will not automatically make more boost sooner. A bigger unit intended to be driven by an engine 2.5-3.0 times the side of the 650 will spool much slower no matter how big the exhaust down pipes and collector may be. This is a basic volumetric calculation. A 650cc motor can only flow a specific maximum CFM of exhaust. The turbo trim of the TC03-6A is sized to make power at 6k rpm. If you want more boost earlier you need to go DOWN in size to a TD02 or maybe an IHI RHB31. These will both spool sooner. Peak boost will be less but it will come on much sooner (less inertia in the rotor and more favorable A/R). Why drop the surge tank? It is pressure cast aluminum and will flow air much better than a log manifold, not to mention is it stronger. The mods you are proposing will cause poor off-idle response. The surge tank has a reed valve in it to allow better off-idle response. The plumbing and elimination of this feature will cause the motor to bog if the throttle is popped open quickly. With a modified surge tank to make the blow-off adjustable, a valve for the wastegate, and an upgraded compressor wheel will make a 650 that will spool up around 4k, give a reliable 16psi of boost (I had mine up to 21psi at one point), and run all day. The other issue is the knock control. The sensor in this engine is set up to retard the timing. Past 15psi you need an intercooler. Past 18psi you will need water or methanol injection. At 21psi my engine was ringing and I could feel the timing backing off. The bottom end of the 650 LJ/LK is stout but at 20psi the pressures on ignition are reaching the point where bearing life on the conrods will be shortened. If you take a step back and look at the work the Yamaha engineers did with this system it is pretty good to produce a reliable and powerful (for the time) engine. The tweaks I listed are minor improvements on a good system. Now, if you'd like to discuss the other factors that can make this motor run a bit better (cam and cam timing changes, oversize valves, etc) we can start another thread. Or we can discuss a turbo 900 motor.
Michael Oberle - Looking for another project
May The Boost be with you. http://ootfab.webhop.net/xj
Last Edited By: PositivePressure
11/05/09 19:30:31.
Edited 1 times.
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