2seater

I cannot say from hands on experience, but the vin C engines ended in the early 90's as the "L" engines were phased in. Some car lines used it later than others, but I do not believe there were any "C" engines with the Tuned Port style manifolds. The Series I, vin L should all have the TPI style intake manifolds and since the basic configuration is the same as ours, the intakes should be able to bolt up. Series II, '96 and later, are a different configuration. I "think" GM installed EGR on the plastic TPI manifolds and there have been stories about the EGR passage leaking but there are kits available to repair. I am pretty certain the EGR operating system is different than the C engines, but if the provision is at least accessible, I would guess our style EGR could be adapted to it? I do not know if the exhaust manifolds are more efficient or better designed, or even if they would fit. The exhaust probably has a different connection for the EGR if used. The stock C manifolds flow reasonably well, and the outlet area can be improved. At the least, the restriction can be removed or it can be cut and welded into a tapered funnel configuration. Careful measurements would tell. Personally I am still running the stock 2.25" system even turbocharged, but a 2.5" system would seem to be a useful upgrade, with no empirical evidence to back it up. The cone style filter offers more filtering area, and lower restriction. Except for full throttle operation, the stock system probably isn't a big restriction but it certainly sounds more powerful I have a lockup delay harness that prevents TCC engagement unless in fourth gear. Generally with everything else stock, it will lockup @ around 50 mph at minimum throttle. You can try it if you would like just to see if it is something you would like to incorporate in a chip. It just plugs in between the harness and connector at the front of the trans. I used to run my engine at 160*F for detonation resistance with the turbo install but it does cost fuel mileage. Padgetts suggestion of 180* seems like a good compromise, with fan programs changed to match. My ancient testing from many years ago showed the acceleration to be best around 140* engine temperature but it isn't practical for a daily driver.

It would seem to be a viable alternative, particularly for urban or limited range use. Honda has been selling a CNG Civic ( the DX model I believe), since the late '90's, although it was only available on the coasts. It is natural gas only wth a range of a little over 200 miles or so. It would seem to be great alternative as a commuter car. The home filling station (Phill) is part of the package. I believe there are conversion kits and retrofit companies available now and I would guess there will be more on the way. Personally, I think it is a great idea if the cost isn't prohibitive. I'm not as sure about the Reatta as a conversion candidate primarily due to the limited storage and weight capacity. I would be interested if additional information turns up.

Assuming there isn't one or more plugged injectors, does this engine use EGR? I have a Ford Ranger (different system) but the EGR is stuck open, which kills engine vacuum at idle (10"-12") or so making the brakes ineffective and it runs horribly at low speed. If I plug the EGR port so there is no flow, I get a lean code on both banks. Vacuum leak or exhaust leak near the O2? I have also seen a very bad timing chain cause hard starting, no power and bad low speed manners (this was 5.0 Ford V8 circa 1988).

Update on the chain tensioner issue: The wear on the new style tensioner has allowed the chain to run at an angle which appear to have worn the front cam bearing to an unacceptable level. The engine was torn down to check for any issues arising from the turbocharger installation and to find the cause of reduced oil pressure. All engine internals look just fine except for this tensioner and the front cam bearing. The front cam bearing is where the oiling system crosses over from one oil gallery to the opposite side. One other related item is the chain itself. The chain that was installed during the original rebulid was a Cloyes brand. It appears to be worn considerably more than the O.E. chain (Morse on the side links), with 1/3 the miles, probably from the twist. Examining the chains closely reveals the side connecting links are .040" below the level of the main links on the Cloyes brand and .012"-.014" low on the O.E. Morse chain. Since the chain is only six links wide, including the side links, the Cloyes chain would tend to wear the tensioner more quickly, at least initially.

I do not know if a later model Series I plastic snakes (AKA Tuned Port) manifold will fit or not. I do know the aluminum version will fit, with small modification to the head (drill two holes for the PCV system). I have tested the air flow through the aluminum TPI and it does not flow appreciably more air, however, the tuning of the intake runners is vastly different. The long runners are designed to help the low and midrange performance. I suspect the plastic version will flow more air with larger and smoother runners. The short runners of the vin C manifold would generally be to help high rpm performance, sort of an oxymoron. The one item the aluminum manifold does not have is EGR. It would have to be programmed out in the chip, or find a creative way to add it. I have been pondering on how to add it to the one I have as I plan to add it to my spare engine when it is reassembled.

Ha Ha Haa! Yes, I understand completely but we don't have a monopoly on that sort of driving. I don't think the chip is useless, but some benefits are not in the pure hp. realm. I should qualify the change in lockup mode. It doesn't prevent the transaxle from going into fourth gear, that's a hydraulic function on the '88-'90, so the low load rpm is similar, but it allows the engine to rev more freely for the transient response you refer to.

I don't think you will see a 20hp increase with only a chip. I have had many chips done, most are for the turbo installation, but I did have two premium fuel chips for N/A use (one was from Fastchips and the other from Ryan @ GMTuners). It can help keep the engine cooler (thermostat and fan engagement), which can help performance a small amount, but it does cost a little in fuel mileage. Another item I had done in the chip was to prevent converter lockup until a chosen speed is reached, such as 50-60 mph. It doesn't have a direct horsepower impact, but it keeps the engine at an elevated rpm when running below highway speed which sharpens throttle response. Open up the exhaust and a free flow intake as well to get the most from what you have. I use the maximum MAF reading to establish a baseline and to see if any changes have improved air flow through the engine. Ambiant weather conditions need to be similar. Use 1.32 x air flow in grams for approx. hp level. A diesel is a different animal when it comes to tweaking the fueling and can't be directly compared to a gasoline engine

Hmmm, I thought both screws must be loose? Both holes are slotted in the sensor and the whole assembly rotates. Maybe I will have to look at it again?

Mine has three tabs and two relays also. Probably for an option I don't have, or, normal GM practice to have one assembly for more than one car line?

+12v to the green connector will tell you if the pump will run or not. If not, it's almost surely the pump. I installed a Walbro many years ago and it has been trouble free. Eliminate the pulsator that sits above the pump in the tank and install a short length of hose. Most kits come with the piece of hose. There are good GM replacements as well if you desire to stay GM, but if you are doing the supercharger install, go with the pump for the S/C cars. The Walbro, either the 190 liter of 240 liter are already an upgrade. As sad and disheartening as it is to have this happen, it is better now. Fuel failure on a boosted engine can be very damaging.

Did you make sure the lever on the throttle shaft engaged the actuator on the TPS? It sounds like they are misaligned.

I agree with you Padgett, just sort of rolled everything into one reply. I don't know why it would require continuous heat either, but the diagrams I found appeared to have constant power applied?

I am certainly no expert on this subject. I have seen comments elsewhere that it speeds up the closed loop operation, but I do not see how that would be possible without reprogramming? There appears to be a couple of possible advantages, one I have observed, and the other is anectdotal from other websites. First, on occasion, I have observed my O2 sensor would become inactive after extended idle periods, ostesibly from becoming too cool. I believe the heater would improve this situation. The second is conjecture that the sensor lasts longer when subjected to alternate fuel blends, such as race fuels (leaded?). I don't know if this may retard harmful deposit buildup or how it may help.

I looked into this a bit further and the heater in the sensor is to be be powered whenever the engine is running. MegaSqurt uses the fuel pump relay to power O2 sensor heater, although I would use an independant relay triggered by an ignition source. It looks like the difference between a three and four wire is case ground for the three wire sensor or independant ground for the four wire. The heater uses two wires in either case. I have a couple of new heated sensors and will check the amp draw as soon as I get the chance.

Three wire? The couple I have fooled with use a standard single wire for the sensor and two heavier wires for the heater, one is grounded and the last one is supplied with 12v from an ignition source. The ones I worked with were not polarity sensitive. Other than that, I cannot help.

You do have to be a little careful with the year of the engine as that is getting close to where they changed to Series II, and that won't work. If the injectors are in the intake manifold, it should be okay. If they are located in the head, all bets are off. I haven't done this mod myself, but F14 (Phillip C.) has, and he wrote extensively about it. There is certainly more to it than just adding the stuff on top, but that was the question.

Yes, they will bolt on. Actually, the supercharger will bolt to the earlier heads, but will need ports drilled for the integrated pcv system (easy). Read through old posts from F14 Crazy who did a similar swap of s/c to LN3 engine many years ago. The crank pulley needs a bit of modifying since the LN3 is slip fit and the latter is interference fit.

Recian, if your exhaust is still stock, a chain type exhaust cutter works well. The exhaust is expanded somewhat on each end of the cat. and there is a resistance weld in that expanded area. If you cut right next to the weld, on the side away from the cat., the cat will slide right out. That will leave a short section of expanded exhaust on each side and a simple straight piece of 2.25" exhaust tubing will slide right in and can be muffler clamped in place, or, the cat can be reinstalled if desired. I used s/s pipe from Speedway Motors.

I have never heard of lack of backpressure affecting the O2 reading? An air leak, either upstream of the O2, or close to it downstream can certainly give false readings. I have been told that the O2 sensor should not be located upstream of a turbocharger as the high pressure does have a negative effect on the accuracy. I have seen many examples of O2 sensors located in the exhaust headers of engines on a dyno for testing (probably wideband) but I would believe that would be a low pressure application? I ran without a cat for more than ten years without discernable problem? Conventional wisdom states 2.2 cfm per horsepower @ 28"wc is required for a zero loss exhaust system. I have posted similar information before but this is a synopsis of what I have found over the years. Please do not take the absolute flow numbers as gospel, but the relationship of one to the other should be accurate. All tests @ 28" wc. unless noted. Stock cat.: 236.1 cfm Gutted stock cat: 322.96 (turbulence?) Walker 2.5" universal cat: 354.64 Straight 2.25" pipe: 495.0 Stock TB/MAF w/o screen: 470.24 TPI TB/MAF w/o screen: 452.15 Install screen in MAF = -25cfm Rear manifold flowed with everything plugged except the front crossover pipe: Stock: 241.52 Stock ported (also ceramic coated): 326.81 Modified w/funnel (per photo): 364.21 @ 20" of water. Actual flow exceeded capacity of 2" pitot sensor scale so test pressure was reduced. EDIT: I only reinstalled a cat. because I tired of the smelly exhaust but then discovered a blown trans. modulator (probably from boost) which allowed the engine to burn ATF. The replacement cat in my example is not sold as a high flow, but it is the actual area of matrix inside that will limit the flow. I suspect a 2.25" through 3" cat. with similar size bodies will actually have similar flow numbers. I used a 2.5" simply for a possible future exhaust upgrade. I still use the stock 2.25" complete exhaust system save for the cat. and a 2.5" Dynomax Ultraflow straight through muffler.

They do make small improvements, just not a dramatic difference. Mileage is pretty much unaffected, unless of course you "use" the improvements regularly. High flow catalytic converters really do flow more, about 40%-50% more. A gutted stock cat. only picks up flow by 30% or so. A smooth cone filter type intake helps on the intake side. All of these things really do allow a greater flow potential, however, much potential is limited by what the engine will actually ingest and expel, and the cam determines most of that. Aside from the butt dyno, a g-tech or racetrack testing, the one onboard way to see if you are actually gaining airflow through the engine is to watch the MAF reading under the same ambiant conditions. The best stock cam is the 1988 version of you can find one.

If you can weld, this is a modified rear manifold in progress. This was done to help the exhaust flow from the front mounted turbo, which it does. It does not help the poor flow from #4, which would require the same mod. on the other side. Just removing the restriction as Barney suggested does help, the flowbench confirms that. The whole stock system actually is pretty evenly matched although #4 is the worst due to the poor design. Easy to see why when you look at the location and angles used. I have a ported version of the stock throttle body, 2mm larger, with a new throttle blade. The biggest hurdle is finding a MAF and throttle body combination that is less restricted, but uses the same frequency response as the stock system, 2kHz - 10.4kHz, at the same flow rate. The 3" inline MAF from a Chevy 3.4 (I think that's what it fits), has the correct frequency range, and flows about 1.55 times the mass at the same frequency, requiring chip recalibration. The stock throttle body and MAF flow pretty much the same wether connected to each other or separately, so GM did a good job matching them. I am presently using the MAF/Throttle body (a one piece unit), from the aluminum version of the TPI manifold, and while it looks like it flows better, it really doesn't. I am using it for convenience and location of the TPS and IAC. As a matter of fact, the aluminum TPI manifold is slightly worse flowing than the LN3, but better balanced. I have not tried the plastic version, which is supposed to be better all around. I have fiddled with changes and "improvements" for about fifteen years (off and on), and while incremental improvements are possible, maybe 15- 20hp or so, boost, or a more aggressive cam, are really needed to make a big difference.

I do have another complete setup that uses both banks of the exhaust that I did many years ago. It actually works too well. I had some tuning issues that were not completely resolved which has been covered in depth previously. This was an alternative to see if a simpler system could be made to work for a low boost application. More development needs to be done but winter weather took the car off the road. I do have several sets of injectors of various sizes and a few different chips from the previous turbo installation. For this limited installation I suspect a small increase in injector size to 22# or 24# will be enough. There is a smaller A/R turbine housing available for the T3 turbo which would likely spool better to get the boost closer to what I want, but I need to optimize what I have now first. The crossover pipe shown doesn't look like it will work to me but perhaps I do not understand the application. One of the largest hurdles to overcome in the physical installation that uses both banks is space to get exhaust up from the rear and back down and out. My previous installation did use a completely new fabricated rear manifold that crossed to the front side on the passenger's side of the engine. Someday I may go back to that install now that I have an intercooler in place which was not part of the original install. Time will tell. Performance hasn't really been evaluated to any real extent. It needs to be tuned to be safe before a lot of that can be done.There is no doubt it is faster, but it is so seamless there isn't anything dramatic, which is what I am really after. Eventually I'll try a G-Tech to see what it shows but my recordings so far are in the sub-seven second range for 0-60. No great shakes but we will see where it ends up.

Good info. I didn't know it existed.

The actual sensor is in a small passage inside the MAF casting. It is removeable from the upper front of the casting and is held in place with three stainless steel screws (non-magnetic). The screen is only to smooth the air flow and it is removeable. A large snap ring holds it in place but it fits tightly. Usually easier to remove the whole casting (four screws) from the throttle body and push the screen out from the inside, or, once the actual sensor is removed, leave the screen in place and reverse flush it with cleaner or just hot soapy water and rinse well. Once the sensor is removed, there is nothing else that can be damaged by simply washing it with detergent, rinse and dry. If the moth was in front of the passage for the sensor, it may very well act as you mention.

I believe the transaxle will lockup the TCC in third gear also, the whole idea being to keep rpm down and maximize mileage. The engine will pull a fairly good load (and hold it) at low rpm but it sure isn't quick. If there is s similar vehicle available, you may want to try one and see if it feels the same. Believe it or not, the Reatta is heavier than a LeSabre of the same year so it takes some prodding to get it to move smartly.