vtec or non-vtec - Honda Prelude Forum

prelude1215 · 11-10-2001, 11:05 PM

I'm planning on turbocharging my lude when I get it. What would be the best model to get for doing this?(vtec or non-vtec?)

Sorry if this has already been discussed but I'm too lazy to search

NOSprelude · 11-11-2001, 12:04 AM

From what I have heard the h23a is the easiest one to tune once the turbo is put on. If vtec has anything to do with that I am not sure.

SLICK96 · 11-14-2001, 10:36 PM

Both can be charged with great results. However, you've got to think about reliability and engine durability after you do this. In the simplest terms, the VTEC engine has more going on once the VTEC cam engages. If you turbocharge a VTEC engine, the compression ratio is one of the main things you'll have to watch out for--it'll get unsafely high (if you want your engine to last very long). If the compression ratio gets too high, your engine will begin to detonate when you boost, and this ISN'T good. You'll have to build the VTEC engine a bit more if you want to boost safely. The H23 (Si) engine has a lower compression ratio, and seems to do better under boost (in terms of engine longevity), from the hours and hours of research I've done, and from what I've heard from Luders who've boosted both H22 & 23's. To all of the engine-GODS out there, correct me if I'm wrong.

Always learning,
Slick96

PreludeNYC · 11-14-2001, 11:40 PM

from past conversations, the H23A since has a bigger block would be better for forced induction, but a lot of factors would contribute to a well built turbo, re-sleeving the block, rods, pistons, valve springs, retainers, and a lot of other internals have to be changed to withstand the extra strain brought about by forced induction, at the same time the H22A as well must undergo a lot of internal mods, so either way you are going to invest a lot just to prep for turboing your Prelude, but like i said, the H23A is better just b/c it has a bigger block or so i have been told, but i always argue since the H22A & H23A are the same except for the head, i always argued they both have the same size block, just that the H22A has a smaller head if that makes sense raising compression...

...ok i am rambling now, but like i said either way you havta change the internals.

On a side note i have seen a lot more Turbo VTEC's with higher Horsepower output then Si's but its all about boost....and possibilit of detonation especially in the VTEC with that high compression...
Si has lower compression mainly b/c of piston shape, or so i have been told... please correct me if i am wrong.

i promise this is my last "ramble" i think of it like this, H23A=Forced Induction H22A=Natual Aspiration
Peace

Merlin1xx1 · 11-15-2001, 10:02 PM

yeah H23A has lower compression...9.8:1 vs. 10.0:1, so not very much, but a bit. if you throw a thicker gasket on you could probably get it to about 9.6:1 thats not too bad for turboing. an H23A would be easier for turboing(simply because of not having VTEC). plus extra displacement(no matter how little) never hurts.

grlielude · 11-15-2001, 10:09 PM

my car...the si gen 4 non-vtec

jpprelude · 11-15-2001, 10:15 PM

Try doing a search on "turbo", "H23" and stuff like that. There were plenty of HEATED discussions on this.

THe VTEC motor has oil squirters, which can improve reliability. I don't really think you can go wrong either way.

Dr. James, 71dsp, marcucci, and inlinefour all know a lot about this.

yellowh23a · 11-19-2001, 08:02 AM

check out hondaprelude.com member: XES. He owns a turbo charged h23 putting down: 345hp to the wheels and 295 ftlbs of torque. Runs a 12.4 @ 112 mph. I've yet to see a turbo VTEC model prelude beat this or even match it. I've seen Civic H/B's with turbo h22s whop this, but that is just due to the difference in weight... Talk to him if your interested in turbo charging a h23a, I'm sure he could give you some pointers.