Alright, its time to lay out the plans and mull it over with you guys for a little refinement.
I am starting with my modified 1997 Toyota Paseo.
I've had the Paseo a few years now and have done several modifications to it. The 1.5L 16V engine currently has a shaved and ported head, bored throttle body, underdrive pulley, cold air intake, and a header with performance 2" mandrel bent exhaust (1.75" is stock). I built it to get more power out of it, and that was fun. But, now its time to get more mileage out of it.
If you click my signature and/or look below you can see that I'm averaging mid to upper 40s out of the car as is. I'd love to see mid 50s out of it and I think thats quite possible especially considering the temperature this time of year.
So, where do we start? First off is probably aero mods. They are cheap and easy to do. The car sees 95% highway as its my daily commuter vehicle, so this will be the most cost effective place to start. I am starting with something that is reasonably good with a drag coefficient of .32 and a frontal area of 19.0ft^2 (1.77m^2). I'm thinking of mosly using a bellypan of sorts to smooth the underbody airflow. There isn't a whole lot of area up front to block for the grill, but I'll be looking into that as well. There is a possibility of rear wheel skirts, but I'm not sold on this just yet. However, any suggestions in this area are very much welcome! I don't know too much about aerodynamics (yet), so help here would be great.
The second area of interest is engine work. I need to do something to get low rpm torque back up. As it is with the ported head and throttle body, plus high flow exhaust, my low end power is sorely lacking.
To remedy this I have already purchased a stock throttle body. It is the stock 45mm, vs my bored 50mm. This should help plenum filling at lower rpms and increase torque accordingly.
The next thing to look at is the head. The porting job IMO is what is the largest contributor to my lack of low end power. The shaving that was done helps counteract it, but not enough. I have yet to find myself a new head to work with, but already have an idea of what I want done to it. The head will be treated to some special work. It will be shaved again to increase compression and thus increase low rpm torque. In addition to that it will have some port work done to it to increase in cylinder air/fuel mixing thus allowing even higher compression without the worry of detonation.
With the following done, a 2" high flow exhaust will definitly not be needed, nore desired. So, the 2" exahust will be replaced with a 1.75" exhaust. I still think this will be a bit larger than I will need, but I have had a hard time finding exhaust components for smaller pipe sizes. Some help here would be great as the Metro engines must use smaller exhausts. This brings us to the header. A header will increase the effeciency/torque of an engine versus the stock exhaust manifold. A header designed for low end torque should do quite well and I am looking into making one. The current header is a 4-2-1 type with 1.5" primaries, 1.75" secondaries, and 2" collector outlet. Its honestly a piece of garbage. Its loud and obnoxious. I do have another header for the car that is a 4-1 design. Its primaries are also 1.5". I don't know if this is the way to go either. I'd much rather design my own 4-1 header and use small 1.375" or even 1.25" primaries. This would be ideal, but we'll see how the other things pan out.
To top all this off, I would like to regearing the car. The Paseo's current transmission has the engine turning 3100 rpm @ 65 mph. I can get my hands on a differential that will drop that down to 2750 rpm @ 65 mph. This should help out on the highway quite a bit I would hope.
I know this is a lot to take in, and thanks for reading if you've actually gotten this far. Any suggestions would be great! I'll be updating this post as I go along. I like to take lots of pictures too so expect to see them as well. Just don't expect any of this to happen fast.
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