What makes the 22 hp difference between a D15B1 (70 hp) and D15B2 (92 hp)?
What needs to be done to a D15B1 to make it a D15B2?

I have an aging D15B2 ('91 DX 4dr) and just got a D15B1 (from a '90 STD) for parts. The B1 looks so new and has almost a quarter of a million miles less on it than my B2, that I would like to just swap engines, but I do not want to loss the 22 hp.

While searching to try to find the answer I noticed that the D15B7 appears to also be the same engine with another 16 hp (108 total). Out of curiosity, what would it take to make the B1 a B7?

 

The B1, from what I've read, has a restrictor plate, different cam, and a shitty manifold compared to the B2 and B7. To get 108 HP from it, you'd need to replace the cam, exhaust manifold, and do an MPFI swap (The B7 is MPFI).

 

you also have a worse ecu with poor fuel maps.

 

Thanks... I will hold off on the B7 idea.

The restrictor plate sounds easy to remove, is this true? Where is it?
I cannot see any difference between the exhaust manifold on the B1 or the B2 I have. How do I tell what I have? Are the two interchangable - Can I put a B2 manifold on the B1? [I do see a difference between the B1 and B2 for '91 in the shop manual, the B1 has the catalytic converter between the radiator and the engine, under the heat shield, and the B2 has the catalytic converter under the car. I do not know what the B1 from '90 is sopposed to look like.]
Can I use the ecu that is in the car for the B2 on the B1 engine?
I have spoken with a cam manufacturer since I suspected this might be the difference - He says that they only list one part for BOTH engines. Is he wrong? (This may be true, I just want to verify what I believe I am hearing.)

 

remember that the B1 its a detuned version of the B2
the loos comes with the diff cam and diff ecu program on fuel map...
also lik they said, the exhaust manifold its a little diff, but in my comparison of both of them, they are the same....

 

hey whats the bigg deal about the STD manifold being like the HF one?? i got an STD manifold and my 90 STD and its a normal header, with cat under the car.....
gergDX if u want ill take that manifold out of ur hands, i want one of those for my turbo setup...

 

what i would do is swap in the std engine, then replace the intake mani with an si one and put an si computer in it as well. that'll bring you up to about 100hp.

 

Thanks again.

You said "...from what I've read...". Can you tell me what you have read. I would like to read it too. I have been looking all over the place and cannot find a good definitive article on this topic.

 

mpfi swap brings you over 108 hp. your compression is higher than that of the d16a6. only crap part about the cam is that it falls on its face after 6500rpm on the d15b1. a6 cam works great but a crower or crane replacement for the a6 cam is even better. then you have to swap out the b1 valve train for that of an upgraded a6 valvetrain to rev to 7500 and still make a lot of power. d15b1s have some seriouse ***** once tuned properly

 

serious,

You did not mention the cam. Is it a concern?

All,

If the cam is a concern, would anybody re-use the cam from the nearly 300000 mile B2, or would you recommend buying a new or reconditioned one to replace the B1 cam? If you are replacing the cam, would you recommend factory B2 cut or a stage 1 performance cam?

JDM EF9,

I need to get my vehicle running reliably first. This will most likely take several weeks to accomplish. After that, I will be looking at what parts are left over and will probably be willing to part with some.

 

well, i said 100 hp, not 108 hp. i'm not sure how much of a difference the cam makes, but just doing the intake/ecu swap should make you happy for a while. as far as reusing the cam, if it's not worn, use it.

 

Isn't the B1 a 12V?

-Dustin

 

the b1 is from the std my 88 std came with it and i still have teh botttom end teh b1 is a 16vavle and it was rated at 70 hp....the ecu program sucks and teh cam is probably the same as teh dx cam...teh intake manifold wouldnt be diff either just detuned for gas milage there is suposed to be a restricter plate but someone tried removing something like that a few weeks ago and it ran like poop...i would find a a6 intake manifold complete with sensors and throtle body...a si distributer and ecu...run the mpfi with stock head ul see good power outa it more than a si if u change teh exhaust and header....mine is more than a d15b1 now somewhere close to 130 hp

 

Here is what I have learned so far (both here and other sources):

ECU: Fuel maps are different - but running the D15B2 ecu on the D15B1 should improve the D15B1.

Manifolds: Sometimes these are different between the B1 and B2. In my case there is NO noticeable difference on either intake or exhaust.

Restrictor plate: I have heard that the B1 has a restrictor plate in the intake system, but I cannot locate it on mine. Help would be appreciated.

Cam: These are different. I finally found spec's for lobe height but still cannot find spec's on duration.
Intake: B1: 1.3728 B2: 1.4411 Diff: 0.0683
Exhaust: B1: 1.3951 B2: 1.4467 Diff: 0.0516
It looks to me that if the B1 was set at the tight end of the spec'd limit for valve clearence and the B2 was set at the loose end of the spec, then the valves' openning's would be the same. Please comment......

 

yeh but running dpfi is pointless its garbage throw it out and get a mpfi intake manifold and teh rest of teh setup its way worth it

 

umm suuuure it does.
d15b2 with mpfi = d15b7 = 102 hp
the difference in compression is .1 which is totally insignificant