Turbocharging a 3800SC??

nocutt · Post by **nocutt** » Wed Jun 21, 2006 5:45 pm

Series8217 wrote:
nocutt wrote:at the end, the results is what matters...
Did you ever get your car done?

U did not get the memo...tennessee fed it to the garbage...three parts :thumbleft:

darkhorizon · Post by **darkhorizon** » Fri Jun 23, 2006 11:19 am

Why is OBDII better than OBDI? The engine control algorithms are the same. The primary difference in code is that the OBDII program is loaded down with a bunch of diagnostic crap that's unnecessary on a modified car.

OBD2 doesnt really do anything drasticly different, there are just alot less "funny" restrictions in the software, and it can be tuned on the fly by "novice" car guys. Like for one, you can set the rev limitter much higher in obd2, and I think a few other very small and mostly insignificant things exist. The quality of signal transmission along injectors and 5volt based sensors also are better on paper anyway, as they use higher quality circuts to handle alot of the more important sensors like maf,map,tps.....

Basicly I am more experienced with obd2, and I know for a fact that an engine can be tuned just as well with obd2 and a $400 powertuner, compared to a megasquirt of the like could do. Also there is alot of support out there, like sample files from other guys with turbo 3800's that would make it a very easy and doable thing for just about anyone that would want to do this.

I in no means say it couldnt be done with obd1, but I think in the long run it would be easier to do with obd2.

Kohburn · Post by **Kohburn** » Fri Jun 23, 2006 11:34 am

darkhorizon wrote:
Why is OBDII better than OBDI? The engine control algorithms are the same. The primary difference in code is that the OBDII program is loaded down with a bunch of diagnostic crap that's unnecessary on a modified car.
OBD2 doesnt really do anything drasticly different, there are just alot less "funny" restrictions in the software, and it can be tuned on the fly by "novice" car guys. Like for one, you can set the rev limitter much higher in obd2, and I think a few other very small and mostly insignificant things exist. The quality of signal transmission along injectors and 5volt based sensors also are better on paper anyway, as they use higher quality circuts to handle alot of the more important sensors like maf,map,tps.....

Basicly I am more experienced with obd2, and I know for a fact that an engine can be tuned just as well with obd2 and a $400 powertuner, compared to a megasquirt of the like could do. Also there is alot of support out there, like sample files from other guys with turbo 3800's that would make it a very easy and doable thing for just about anyone that would want to do this.

I in no means say it couldnt be done with obd1, but I think in the long run it would be easier to do with obd2.

how about making it function properly as a manual? how difficult is that with OBD2?

The Dark Side of Will · Fri Jun 23, 2006 12:35 pm

What is a power tuner and how well would it work with, say, Cadillac Northstar controls?

Mach10 · Post by **Mach10** » Fri Jun 23, 2006 2:06 pm

darkhorizon wrote:
Why is OBDII better than OBDI? The engine control algorithms are the same. The primary difference in code is that the OBDII program is loaded down with a bunch of diagnostic crap that's unnecessary on a modified car.
OBD2 doesnt really do anything drasticly different, there are just alot less "funny" restrictions in the software, and it can be tuned on the fly by "novice" car guys. Like for one, you can set the rev limitter much higher in obd2, and I think a few other very small and mostly insignificant things exist. The quality of signal transmission along injectors and 5volt based sensors also are better on paper anyway, as they use higher quality circuts to handle alot of the more important sensors like maf,map,tps.....

Basicly I am more experienced with obd2, and I know for a fact that an engine can be tuned just as well with obd2 and a $400 powertuner, compared to a megasquirt of the like could do. Also there is alot of support out there, like sample files from other guys with turbo 3800's that would make it a very easy and doable thing for just about anyone that would want to do this.

I in no means say it couldnt be done with obd1, but I think in the long run it would be easier to do with obd2.

Tuning with power-tuner will be somewhat ungainly, given that there are not many good tools that will let you actually visualize the fuel-maps.

Tuning on a dyno would be best, but still awkward, as you will be fine-tuning each increment.. Yucky!

That is, if we're thinking of the same device; (little hand-held device with a 40chr LCD).

ODB is nifty because you can use programs to generate the entire 3d maps of fuel and spark curves.

I haven't yet heard of any ODB2 program that will do that to production ECMs...

nocutt · Post by **nocutt** » Fri Jun 23, 2006 11:30 pm

Are we confusing the software used to read this programs with the actual proGRAM...?

OBD1 has been around since well forever...lol, so many programs have been tailored to fit this modus...OBD2 is more resolute, like I say you can be the one that sees this as a "curse or blessing". I mean do you actually think GM for example builds a fuel map, timing map or boost map for that matter using a PCM suite like power tuner or HPT? The point here is OBD2 uses more sensors and hence more feedback...Now if you build a tool that can "read" encoded data, the hardware/software should keep up with both the times and the data...and strictly speaking this is where we are at today...OBD2 PCMs have so much resolutions and bulk data it is very difficult trying to decode...Building a fuel map especially based on Real time is very doable...but that is the sole function of the software/hardware...believe me the data is there...
Say...what was the thread for anywayz :bootyshake:

fieroX · Post by **fieroX** » Sat Jun 24, 2006 1:20 am

The Dark Side of Will wrote: FieroX is using the SC manifold with SC intercooler and custom upper manifold. He no longer has the SC case.

actually I have a water to air (spearco 2-230) thats mounted under the car. The ones that sit under the SC are very small (core size like 4"x6" and 2" thick. My core is 9"x10" and 4.5" thick, and will support up to 1500 cfm.

www.fieroX.com/intercooler/ :thumbleft:

The Dark Side of Will · Sat Jun 24, 2006 9:32 am

nocutt wrote:Are we confusing the software used to read this programs with the actual proGRAM...?

OBD1 has been around since well forever...lol, so many programs have been tailored to fit this modus...OBD2 is more resolute, like I say you can be the one that sees this as a "curse or blessing". I mean do you actually think GM for example builds a fuel map, timing map or boost map for that matter using a PCM suite like power tuner or HPT? The point here is OBD2 uses more sensors and hence more feedback...Now if you build a tool that can "read" encoded data, the hardware/software should keep up with both the times and the data...and strictly speaking this is where we are at today...OBD2 PCMs have so much resolutions and bulk data it is very difficult trying to decode...Building a fuel map especially based on Real time is very doable...but that is the sole function of the software/hardware...believe me the data is there...
Say...what was the thread for anywayz :bootyshake:

Not sure what point you're trying to make about OBDII...

Yes, there are more sensors... The utility of those sensors is debatable. Post cat O2 sensors don't contribute to running the engine any better. High resolution crank sensors don't contribute to timing accuracy, just misfire detection (and not for the purpose of making the engine run better, but for the purpose of reporting consistent misfires via a trouble code).

Now the computing hardware on which OBDII systems operate is more advanced than OBDI hardware, and the software takes advantage of that, via 16 bit RPM counters, for instance, so RPM doesn't have to be scaled to an 8 bit value. However, if that's an advantage to you, you must be building an engine that will rev high enough to take advantage of it... which isn't a 3800.

Now Ryan Hess has written a patch to allow his particular OBDI system to go beyond the limitations of the RPM/25 algorithm, so there goes the advantage of OBDII in that regard.

OBDI systems can deal with RPM significantly higher than what they can report. Within the program, RPM is "understood" as the number of counter ticks between trigger events... this quantity gets *smaller* as RPM goes up... the only significant limitation is in reporting that RPM (and the fact that the tables only go up so high, but that's just a matter of programming).

IOW, I don't see a significant advantage to OBDII on an engine that's in good condition, other than easier dealings with high RPM engines.

You are aware that OBDI computers, at least GM ones, can be tuned on the fly--without shutting the engine down, aren't you? Can that be done with OBDII?

nocutt · Post by **nocutt** » Sat Jun 24, 2006 5:39 pm

My friend then we are saying the same thing in fact...look at how long tuners have used Obd1 compliants systems...then look how long obd2 compliant systems have been decoded in regards to performance...concurrently obd2 'reprogramming' is still infantile...are you telling me when GM are tunning their high end vehicles they would have to revert to switching said vehicles off...No I don't buy it...that is wasted time...
Again this will end up turning into a semantic argument...the power is in the program(ER). Either 'a curse or a blessing'...it is just the complexity of said systems that make most markets avoid them...I digress, the ends not the means...

Kohburn · Post by **Kohburn** » Mon Jun 26, 2006 7:51 am

nocutt wrote:My friend then we are saying the same thing in fact...look at how long tuners have used Obd1 compliants systems...then look how long obd2 compliant systems have been decoded in regards to performance...concurrently obd2 'reprogramming' is still infantile...are you telling me when GM are tunning their high end vehicles they would have to revert to switching said vehicles off...No I don't buy it...that is wasted time...
Again this will end up turning into a semantic argument...the power is in the program(ER). Either 'a curse or a blessing'...it is just the complexity of said systems that make most markets avoid them...I digress, the ends not the means...

so what yopu are saying is that it'd be better than OBD1 if it wasn't such a pita to program

The Dark Side of Will · Mon Jun 26, 2006 8:31 am

I guess that's what I took from that as well.... "OBDII will be great when the aftermarket gets to the same level of development as OBDI"... which is a tacit admission that OBDI is more developed...

GM has their own stuff that's nothing like what that aftermarket would use to program a car. Mass production environments are pretty wild. A few seconds saved here and there can be very important.

Jinxmutt · Post by **Jinxmutt** » Wed Oct 31, 2007 6:26 pm

I'm bringing this back because I didn't want to start a new thread about it. I'm ordering the parts for my crossover and i was unsure which size to go with.

Should I go with 2.25" or a 2.5" crossover? I'm making 3-1 basic headers to a v-band flange and then the crossover will have a v-band to each header with a single v-band to an adapter. The adapter is a v-band to t-4 flange which is where I will also mount the pipe to the tial 44WG and attach the support bracket. Making the intermediate piece will allow me to rotate the turbo so i can more easily fab the downpipe if its not perfect the first time. Plus it allows for easier placement of the WG.

Is 2.5" too big for the crossover?

Sinister Fiero · Post by **Sinister Fiero** » Thu Nov 01, 2007 3:19 am

Wow, how did I miss this thread? Anyway, here is my $0.02 to add to the discussion...

Concerning the use of a gutted SC housing; why? Basically it's a big open box with no runner length at all. So that means you will have a large open space for a bunch of turbulance to build up in; as well as uneven air distribution concerns when you start running a lot of boost. In addition, throttle response and off-boost power will suffer compared to what I am using (L36 camaro intake). The intake I am using is cast just like a tunnel-ram; it has shorter runners than the FWD L36 intakes but still longer than the virtually non-existant L67's intake and SC housing. My car has such good throttle response and off-boost power that it can actually spin the tires before the boost comes up -- on asphalt anyway. And when the boost does hit, you had better have the wheel straight or you will be facing the other way quickly.

Now, concerning this OBD-2 vs. OBD-1 discussion, there are a few things I want to put to rest right now...

1) OBD-1 doesn't limit your power. If you believe that, then you need to go over to the Turbo Buick Grand National community and see how many people are running 9's and faster in the 1/4 mile on the stock 86-87 ECM (custom chips of course). And that computer is just as slow as the stock Fiero ECMs; which are WAY less capable than the OBD-1.5 3800 PCM I am using in my car.

2) The MAP sensors used on OBD-2 systems don't really serve any vital function; at least while the MAF sensor is working properly. The timing advance is based on cylinder load (air mass); which is calulated using the MAF readings. Same for fuel. Hell, even transmission shift points and line pressure are controlled based on the MAF readings. So just because the OBD-1 computers don't have a MAP sensor doesn't make them inferior.

3) OBD-1.5 (94-95) 3800 PCMs use the same crank sensor, cam sensor, and ignition module as the OBD-2 computers. Yes they also have a misfire detection function just like OBD-2. So in that respect there is no difference between the two.

4) The main limitations of concern the OBD-1.5 system has is it cannot have the rev limiter set above 6400 rpm (unless you disable it); and it cannot control a 4T65-E transmission (because of the pressure control solenoid). Aside from that, the OBD-1.5 system is every bit as capable of running any L67, L36, or hybrid as OBD-2.

5) Concerning the wiring, "higher" quality circuits, 5v ref bussing, grounds, etc comments that have been made (in reference to the OBD-1 systems being inferior)... Where the hell do you guys come up with this? If you read or heard this somewhere I think you need to consider the source of these rumors. The people making these statements don't work with OBD-1 which means they don't know crap about them and are just trying to sell you on OBD-2 so they can make a buck. It's that simple. I do both OBD-1 and OBD-2 tuning, and have been doing it for many years. I can tell you that I prefer OBD-1 over OBD-2 (3800 applications) whenever possible. It's just easier to work with and tune; and it works just as well (except for the restrictions mentioned earlier). Of course I have hacked a bunch of the code myself just so I could add some tunability to some of the tables that I wanted to play with; which is the beauty of the tuning software that is currently available for OBD-1. How many OBD-2 tuning software packages allow you to go in and add tables yourself?

6) Real-time tuning. Can't do it with OBD-2 3800 PCMs right now that I am aware of. The hardware is available (Moates roadrunner) but there wasn't any software support last time I checked. So every time you want to make a change, you have to shut the engine off and reflash. Nice way to run up the meter when you are renting out the dyno. Because of OBD-1's removable chips, emulation is as easy as buying an emulator from your favorite vendor and going to work. And as soon as you start emulating, you won't ever want to go back to the "old" way.

But getting back to the original subject of this thread; my turbo setup has been together for over 4 years now with NO major failures. The only failure I have suffered to date was a broken CV axle because I tried using a light-duty axle; I have since upgraded to a medium duty axle and haven't had any issues since. But then again I'm not running slicks either. My best 60' time to date is only 1.7 sec. And I do have a traction issue when I try to boost up at the line. Can't leave with more than a pound or two of boost or the tires get blown off. Aside from that, the engine produces more than enough power for a daily driver. And that was the whole point of this little experiment of mine -- to see how far stock parts could be pushed before they became unreliable. So far I haven't hit that threshold (aside from the aforementioned axle issue); but then again I am very smart with this car. I always let it warm up fully before beating on it; I always let the engine idle for a while after beating on it so all parts can cool down; I always run synthetic oil but change is as if I was running conventional; and I always keep a close eye on my engine's operational health (fuel and spark). I also don't get greedy with the boost. The maximum amount of boost I have ever put on this engine is 15psi; and that was when I was running 110 octane race gas. That's when I ran the 12.26 et. Is there more in there? Sure. But I just haven't had the time this year to fool with it and push it more to see how much more it can do. Maybe next year.

Jinxmutt · Post by **Jinxmutt** » Fri Nov 02, 2007 2:09 pm

I think I'm just going to settle with 2.5".

Sinister Fiero · Post by **Sinister Fiero** » Fri Nov 02, 2007 2:34 pm

Jinxmutt wrote:I think I'm just going to settle with 2.5".

I'm using 2.25" for my crossover/turbo feedpipe. Didn't see the point in running anything larger since the outlets from my manifolds and the inlet to the turbo was only about this size anyway.

nocutt · Post by **nocutt** » Mon Nov 05, 2007 9:09 pm

Darn Ryan glad to still see you around this corner of the woods...lol! Did you ever upgrade the turbo (I remember you were using a stock GN turbo)?

Wanted to quickly point out...real time tuning is possible on the (last I heard) 3800 pcm, however I think there is some sort of patent infringement on the issue...

Jinxmutt wrote:I think I'm just going to settle with 2.5".

As already pointed out...no point unless you are running a.) big hairdrier that necessitates it or b.) serious horsepower...
you need to be able to keep up velocity...2" or 2 1/4" IMO is maximum...force the turbine to do more work!!

Sinister Fiero · Post by **Sinister Fiero** » Mon Nov 05, 2007 9:18 pm

nocutt wrote:Darn Ryan glad to still see you around this corner of the woods...lol! Did you ever upgrade the turbo (I remember you were using a stock GN turbo)?

Wanted to quickly point out...real time tuning is possible on the (last I heard) 3800 pcm, however I think there is some sort of patent infringement on the issue...

Well like I said I know the hardware is available for emulating the 3800 PCMs because it is out for the LS1 units. But I haven't seen any tuning software vendors selling real-time tuning software for the OBD-2 3800 PCMs yet which might be because of what you said.

Yes I am still using the stock GN turbo and it's still going strong. I'm sure I running it to it's limit on this engine at 15psi but I hesitate installing a larger turbo until I build the engine to take it.

nocutt · Post by **nocutt** » Mon Nov 05, 2007 9:45 pm

Sinister Fiero wrote:
nocutt wrote:Darn Ryan glad to still see you around this corner of the woods...lol! Did you ever upgrade the turbo (I remember you were using a stock GN turbo)?

Wanted to quickly point out...real time tuning is possible on the (last I heard) 3800 pcm, however I think there is some sort of patent infringement on the issue...

Well like I said I know the hardware is available for emulating the 3800 PCMs because it is out for the LS1 units. But I haven't seen any tuning software vendors selling real-time tuning software for the OBD-2 3800 PCMs yet which might be because of what you said.

Yes I am still using the stock GN turbo and it's still going strong. I'm sure I running it to it's limit on this engine at 15psi but I hesitate installing a larger turbo until I build the engine to take it.

hahahaha...the more reason to even install a bigger unit...
drop in a large unit, if engine lets go (which I doubt) then you have a better reason to do a nice 'hummadrumma' build...

Sinister Fiero · Post by **Sinister Fiero** » Mon Nov 05, 2007 9:49 pm

nocutt wrote:
hahahaha...the more reason to even install a bigger unit...
drop in a large unit, if engine lets go (which I doubt) then you have a better reason to do a nice 'hummadrumma' build...

Nahh; that's ok. I really enjoy driving the car too much and would rather take my time and build a motor up for this car without being in a hurry to get it done just so I can drive the car again.

But in truth I think I am going to put that build/upgrade on hold until I get my GN and build it up the way I want it. So it could be a while before I come back to this car and really make it scream.

Post by **eHoward** » Mon Nov 05, 2007 9:56 pm

i'd appreciate it if you removed the link to the scanned copy of maximum boost.

i think anyone on here should be able to drop $20 on a copy or visit a local library.

thanks.

Jinxmutt wrote:I think I'm just going to settle with 2.5".

btw,