Ressurection of a 91 Prelude 2.1 SI

[AzN_DvL]

Hi I'm new to this forum and the reason that I joined is so that I can resurrect a 91 Prelude 2.1 SI that I just recently acquired. At the moment the car's engine has been dismantled in certain parts and is undriveable but hey who cares right? This is why it's a project car. I've got major plans for this car such as not just rebuilding it but to upgrade it and hopefully push the car to 300+ HP. I read a few articles in the form such as adding turbo, doing swaps, etc. but the route I will be taking is to keep the B21A1 engine instead of swapping for a H engine. I've been researching on many parts but have found little to do the job. I believe that what I would need to upgrade are: cam shafts, camgears, get hi compression pistons like maybe 12.0.1 ratio, flash my ECU or replace it (I've always heard that it's better to reflash it then replace), performance intake manifold, a cold air intake/short ram intake (I know the difference between them but at this moment I'm not sure which would be better for the car), performance headers, exhaust, and the turbo kit. Any ideas/thoughts/suggestions would be greatly appreciated. Thanks!

PS Here's what the car looks like now

[spiffyguido]

AZN,

First let me be the first to welcome you to the forum and congratulate you on your purchase of a '91 Honda Prelude. They are fantastic machines, and I'm confident you will enjoy being an owner.

Your car looks good. True, it needs some work, but it has potential. Restoring a car is always a very rewarding process as the end result is entirely up to you.

Since you're just starting into your project, the best advice I can give you is to start researching and define your goals early. If you're planning on getting 300HP out of the car, I would propose to you that this will be most easily achieved by running a forced induction system of sorts. Turbo is probably the way to go for you as this is the simplest way to make big power without investing obscene amounts of cash. I admire you choice to stick with the B21 as it is a great engine, and really underappreciated by many, in my opinion.

If you do plan to go turbo, you're going to want to focus most of your energy on strengthening the internals of your engine and improving the fuel system. Cam shafts and cam gears are nice, especially for a perfect tune, but for your power goal, you should focus more on the pistons and rods. For you, you'll actually probably want to lower the compression ratio to help protect you from detonation. Turbo cars often run lower compression to reduce detonation. You'll want to get forged rods that are strong enough. Don't worry about your crankshaft, as it can easily deal with that much power, but make sure your bottom end bearings and oiling system are in excellent shape as these will take a pounding.

If you go turbo, you won't need to worry about a cold air intake, as the air will be charged from the turbo. Your exhaust manifold will have to be a turbo manifold for the turbo of you choice. I would suggest however that you plan on getting a larger exhaust system. 2.5" diameter or higher should do nicely. Turbo engines don't rely on the back-pressure provided by a smaller exhaust for running, so you want exhaust to be able to escape as quickly as possible.

Because you have a B21, your ECU is a PK3 ecu, which is OBD1. This means that you can reflash your ECU to match your needed specs. You may also have to upgrade other parts of your fuel system though such as the pump, regulator, and of course, injectors.

As you begin work, I would suggest that you spend a few bucks and buy yourself a few decent books on forced induction as these are invaluable resources. Write ups and tips from others are helpful, but at the end of the day, you need to know your stuff to get that kind of power. It is absolutely achievable, and I know people who have done it, but you do have to get a lot of things right to have it be reliable. I can suggest some reading material if you haven't already got some.

In the meantime, please post often about your project, or anything else that interests you, for that matter. We even enjoy fun stuff finding it's way into the off-topic forum.

Lastly, keep your eye open for a user called CADster on this forum. He has experience with turboing Preludes and no doubt would have some good pointers for you.

Thanks for visiting. Tell your friends.

[AzN_DvL]

Hey spiffyguido or to whoever,

What do you think about adding LSD to the car? I read online that a few 3rd gen lude owners putting it in but it seems like something that's out of my league and would require professional services. Any tips? Or should I stay away?

[spiffyguido]

It's true, LSD would be nice.

I know that the LSD system from an ITR can be fitted to a 3rd gen prelude. I'm not sure exactly how hard this is, but messing with transmissions is usually touchy business. The only person that I know for a fact has done it is MustardCat. His website is: http://www.prelude3g.com/. Details are under the transmission section.

For now, you might find it best to focus on getting the engine sorted out and then work on the tranny once the car is running again.

[AzN_DvL]

True, that's a valid point. I'll reassembly and upgrade as i go along and post pictures of my progress. Thanks

[nu2prelude2]

Be warned, know what you're getting into with high compression ratios. If your'e an expert, that ignore this but if not, you're playing with fire (literally) I ran High compression V-8s in my racing days and they were "tempermental" to say the least. Mine were fuel injected so there's not alot of fundamental difference between domestics and imports at those compression levels
In my racing days, I never saw a prelude run a 10.0 in the 1/4 mile. I hope yours does one day

[AzN_DvL]

Hey peeps,

Thanks to all those who stopped by and visited this forum - shout out to Spiffyguido for some serious feedback and also nu2prelude2, but it saddens me deeply to say that this resurrection has been interrupted until further notice. As of today, May 26, 2009 when I came home from my errands that my lude was missing. Yes it was stolen from my drive way. I wasn't even half way done with the resurrection and someone had the nerve to come jack my lude. I did find out some info on what happened because my neighbors were doing work and noticed a tow truck towing my whip. I contacted the towing company that 2 eye witnesses identified and they stated that they do not have any paperwork on a towing at my house. A police report was already done and all I can do now is hope to get it back but who knows it may have already been chopped. But do believe that if I catch the mofo who towed my baby away I will seriously sue them to the fullest extent legally possible. A great way to end my Memorial Day weekend. Again I appreciate those who visited this to see the progress which wasn't much because the real action was suppose to happen next week. My luck with the ludes (3rd Gen) isn't looking too well because I owned one as my first car and someone totaled it by rear ending me and now this one was stolen. So sad I am...Good luck to all of my lude lovers and if I do pick up another I will certainly be back.

[spiffyguido]

Dude that sucks! I hate hearing of stories like this.

Post up some pictures if you have any so that people can be on the lookout. I hope she comes home to you.