does anyone know any ways to squeese more hp out of the d15? i'm running in stock and the 89-91 civic si's are killing me. the 4 speed is making matters worse (70 mph in 2nd and still not hitting the limitter) and there making 30+ more hp. i know i'm not gonna get that out of some little adjustments, but any little bit will help.

 

All the "good" ways that I can think of are illegal for stock classes.

However, do a K&N drop-in filter, good flowing exhaust, make sure your cat isn't plugged and the dist., plugs and wires are fresh. Other than those, that's about all you can do, besides a standard 20 over motor rebuild with stock parts.

If it is purely a soloII car, lose the a/c and radio if so equipped (because on the STD those were options).

Good luck

 

its purely a solo 2 car with some track days posibly later on.i definately have both ac and a radio. gonna look into removing both this week or next (in time for the next points event) thanx for the tip

 

are you allowed to balance your motor? what about blueprinting the engine and fuel system. Kinda costly, but might give you some Hp.

 

Yeah, you can do everything within factory specs. But unless you can do the labor, it would probably be cheaper to buy a better car and start from there.

 

I thought in the recent revisement of rules and classes, that they allow for the STD 4spd civics to now swap in 5spd trannies.I think I read that in the recent Honda Tuning magazine which feature a D15 powered Auto-crosser.Under the class table diagram it shows #'s next to # 5 it states-
"The STD and DX are treated the same under production rules.Use of five speed in the STD model is allowed.This limited prep classification limits compression to 10:1 and retains use of the dual-point,throttle body fuel injection.Valve lift is limited to .390 in." Well, I hope that helps?
Later-cool

 

In Street Prepared yes. In stock classes, no.

 

TIRES TIRES TIRES &

Alignment

 

Are you allowed to do engine work?
I ask this because you can gain some HP by swapping a complete Si head onto your D15 block. Si head is more performancey than a complete D15 head/intake manifold.

..and like people said above, run an Si tranny; while your at it, get your stock flywheel lightened

 

Unfortunately, all illegal in stock.

If you must stay in stock, all you can do is keep the engine in good tune. Have your fuel injectors cleaned. Use a K&N drop-in filter. Get a good catback. Use good plugs, wires, and a new dist carp/rotor. Set up the suspension properly (new stock bushings, tie rod ends, etc and an alignment). Make sure the engine is at the proper coolant and oil temps, if it's not find out why.

 

The plain, hard, painful truth is that you can't get much performance out of the dual point injection. It is just not a modification friendly system, and no matter how much work you do, that will always be your limiting factor. Trying to mod the car is throwing money away. I tried to race a DX, and gave up and switched to the Si intake manifold. Now I'm mating that to a 1.6L bottom end, to make it into a normal Si that I can race H4 in honda challenge. The good news is that so many CRX Si owners switch to the ZC or other B-series engines that the Si 1.6L engines are pretty easy to get. That is my recommendation....

Matt

 

That doesn't work in SCCA SoloII. Well, not easily anyways. Trim level and model changes must complete, so putting in a same-year Si motor would require an Si interior, wheels, brakes, and whatever else if different.

For SCCA IT, it is possibly legal. You need to come up with the required number of VINs and make damn sure nothing in the required equipment is different. The VW guys build GTIs from lesser Golfs frequently.

 

so basically, i'm stuck. well, that sux. i think the plan will be later on to prep the car for sts with a d16 and 5 speed since, as far as i know, it is legal to do that in sts.

 

Here's ome intersting info for you guys if you didn't already know:

The STD motor makes only 70hp while the DX motor makes 88hp from 1988-1991.

They are both 16-valve, 1.5L, dual-point programmed fuel injected, yet the DX has an 18hp advantage along with the 5-speed tranny.

Now if my memory serves me correct the STD 4-speed tranny is geared the same as the 1-4 on the DX, right? I used to work at a Honda dealer back in 1996, so I read all the service specs in the fronts of the shop manuals and I *think* I remember reading that.

EDIT

The STD model tranny and DX tranny are definateky different other than just the obvious 4 and 5 speed configurations. I *believe* that the STD probably has a similiar 3.25FD while the DX probably has the higher 4.06 like the 1992-1995 DX.

I used to pay close attention to the STD model because I owned a 1990 Red STD model back in the day.



I'm guessing that the main difference in the STD and DX motors might be the cam?

It's so much easier to know the difference in the 1992-1995 CX and DX motors because one is an 8-valve while the other is a 16-valve, and the trannies are WAY different with the CX having farther-spaced gears and a 3.25FD while the DX sports closer gears and a 4.06FD if my memory serves me correct.




[Modified by B18C5-EH2, 5:15 PM 6/17/2002]

 

Basically what I might have been trying to say was it could be possible to swap in the DX motor un noticed, right?

I'll check the block codes and see what, if any differences are.

 

Won't work because the 89-91 Civic Si is listed on a different line in SP than the other Civics.

Best advice is to look for at least a DX or Si. DX will make a good STS car also because it is lighter than the Si.

 

The STD block code is D15B2 - what is the block code for the Dx engine?

Is it not the same D15B2 on both STD and DX models?

If so, then a DX swap wouldn't really be a big deal, right? Would it not go completely unnoticed if they share the same block and head codes? Or how about a DX cam swap *if* that's the main horsepower difference?

I'm not one for cheating, but with 70hp, crappier tranny, and nearly the same curb weight I'd say that the STD is classed horribly if it's in the same class as the DX.

**EDIT**

I'm a moron - was supposed to be D15B2, not D15B7.




[Modified by B18C5-EH2, 5:50 PM 6/17/2002]

 

The STD, DX, CX, VX, whatever are all in HS--the lowest stock class you can get.

IN street prepared they all go to FSP--the lowest SP class there is.

Not every car is going to be competitive, and this one is no exception. And the D15B7 is quite a bit different (in terms of injection) in the 92-95 cars. I thought the 88-91 DX motor was D15B2?

 

i am confused now. in a previous post i mase asking "what can be done under the hood in sp" i followed a link posted by someone that said the 88-91 civic went to csp. that would make the car useless there because of the crx. but if id indeed goes to fsp, that would be better. i think a well prepped vw may be faster, but for me locally and reigonally, i think it would be ok. however, i have heard both csp and fsp. so i'm gonna have to check into it a bit more to be super sure before i start building it for sp.
the 88-91 dx had the d16. i don't remember which one, but it made about 80-90 hp where as the d15 of that year made 70hp and 83ftlbs (which is what i'm runnin with.)

 

88-91 Civic:

STD = 1.5L 70hp
DX = 1.5L 92hp
Si = 1.6L 106hp

 

Where'd you get that info?

I'm pretty sure that the DX is 88hp and I'm sure that the Si models had 108hp, not 106hp.

Not really trying to argue, but I'd like to know if I'm wrong.

 

Type
Transverse Inline-4, Aluminum Block and Head, Front Wheel Drive (AWD offered on wagon)
Throttle Body injection (1.6L engines have PFI)

Valvetrain
Sohc 4 valve/cyl.

Displacement
97 cu in./1590cc (Si, AWD Wagon)
91.1 cu in/1493cc (STD, DX, LX, Wagon)

Bore x Stroke
2.95 x 3.54 in./75.0 x 90.0 mm (Si)
2.95 x 3.33 in./75.0 x 84.5 mm (STD, DX, LX)

Compression Ratio
9.6:1 (88-89 CRX HF)
9.1:1 (Si)
9.2:1 (STD, DX, LX)

Transmissions
4spd manual: base 3dr
5spd manual or 4spd auto: DX/LX/2WD wagon/Si
6spd manual or 4spd auto: 4WD wagon

Horsepower (SAE)
62hp@4500 (88-89 CRX HF)
70hp@5500 (base 3dr)
92hp@6000 31/35mpg 5spd (DX/LX 3dr/4dr, 2WD wagon)
108hp@6000 28/32mpg 5spd (Si 3dr, EX 4dr, 4WD wagon)

Torque
83lbs/ft@3000 (base 3dr)
89@4500 (DX/LX 3dr/4dr, 2WD wagon)
100@5000 (Si 3dr, EX 4dr, 4WD wagon)


Oops....off by 2hp on the Si model.

 

Thanks.

Where'd you get that from? Looks like something I need to look at too.

So the DX has an even larger horsepower advantage than I had previously thought!

 

http://civic.vtec.net/

Page is somewhat inaccurate on the 92-95 stuff (weights), but otherwise it is decent for a few specs.

 

ok, so now that we've goten the hp issues worked out. i guess theres no way to squeese any hp out if the std 1.5. i was thinking of an exhaust, but i don't wanna loose any of the 83 foot pounds of torque i got. i need a rulebook to see where i can go and what i can do there