Want 150bhp from Z6

D15, D16, D17 and Mini-Me swaps
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Want 150bhp from Z6

By SL93ex
- Thu Mar 31, 2011 5:13 am #247261 Hi... I'm looking for some affirmation on a future DD build.

I've got a solid Z6 that will be getting a new timing belt/water pump soon.
So I'd like to prep the head in advance and do this all at once to minimize down-time.

I'm thinking a Y8 head + Y8 head gasket will get me to about 9.5: cr, right? I can source a Y8 head locally for under $50.

Some minor port work (I've done some on SBCs in the past, and I'm aware of anti-reversion stepping). Clean up the chambers, new guides/seals, maybe springs/retainers, and lap the valves.

Add I/H/E (ebay crap) and I should be hitting 150bhp without a problem, yes?

I'm not looking to win any races or track days... just a little sharper throttle and a little more entertainment for the highway on-ramps.
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By dbrooks
- Thu Mar 31, 2011 5:20 am #247263 im not 100% that all of that would yield the gains you're wanting. i'd probably do some searching in the N/A section of this site! :thumb:
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By chrono404
- Thu Mar 31, 2011 5:47 am #247264
dbrooks wrote:im not 100% that all of that would yield the gains you're wanting. i'd probably do some searching in the N/A section of this site! :thumb:

x2

Pretty sure with out a cam and tune you wont hit 150 at the wheels.

Doing what you say will bring it to life. however, it wont give you 150hp. To get that on a D Series you will need bolt ons (i/h/e + intake mani) then a Cam and tune.
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By OleFolk
- Thu Mar 31, 2011 6:02 am #247267 Also if your trying to get that much
You cant just throw on any random, shotty I/H/E setup
I mean you can, but its better to get a setup idealistic to what you want
And of good quality

You will need headwork done and an a good tune but its completely realistic
Plus it seems the honda aftermarket is getting bigger and cheaper
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By dbrooks
- Thu Mar 31, 2011 6:30 am #247273 what i would do instead of having the head work done, is look on craigslist or a local forum for an already ported & polished head. when you look at it, make sure everythings in good shape. that's what i did when i was going to do a mini-me and i got a super good deal.

By AutoXCivic
- Thu Mar 31, 2011 12:00 pm #247326
chrono404 wrote:
dbrooks wrote:im not 100% that all of that would yield the gains you're wanting. i'd probably do some searching in the N/A section of this site! :thumb:

x2

Pretty sure with out a cam and tune you wont hit 150 at the wheels.

Doing what you say will bring it to life. however, it wont give you 150hp. To get that on a D Series you will need bolt ons (i/h/e + intake mani) then a Cam and tune.


BHP is not the same as WHP. But you do make a valid point, definitely need a cam and tune and while you're messing with the head you should mill it down to bump your compression up even higher. If you are looking for 150 WHP, you're going to NEED to get up in the 11+ CR range. I had a 10:1 motor that was only making 120 WHP, granted that was a 1.5 but I don't think the extra 100cc is going to make up 30 whp.

Unless, of course, you want to boost the little bastard.
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By 94EJ2
- Thu Mar 31, 2011 12:09 pm #247328 arent the z6's rated at 130bhp stock?

i dont see how getting it up to 150whp would be that hard. intake exhaust and maybe a cam should get there no problem :?

By SL93ex
- Thu Mar 31, 2011 12:48 pm #247351
dbrooks wrote:what i would do instead of having the head work done, is look on craigslist or a local forum for an already ported & polished head. when you look at it, make sure everythings in good shape. that's what i did when i was going to do a mini-me and i got a super good deal.


I'll do the port/chamber work myself... open up the short radius/divider area a little, smooth the guide boss, taper the guide, smooth the seat area... etc. Old school stuff :) I'm only going to have the head resurfaced at most. I definately don't want to go much more than 10:1. And I definately want to avoid any lengthy tuning sessions... As it is, the tune will cost as much as the build.

And again, I'm only looking for 150hp at the crank, so 120hp at the wheels sounds about right.
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By Eg6H2D
- Thu Mar 31, 2011 8:09 pm #247431
chrono404 wrote:
dbrooks wrote:im not 100% that all of that would yield the gains you're wanting. i'd probably do some searching in the N/A section of this site! :thumb:

x2

Pretty sure with out a cam and tune you wont hit 150 at the wheels.

Doing what you say will bring it to life. however, it wont give you 150hp. To get that on a D Series you will need bolt ons (i/h/e + intake mani) then a Cam and tune.



^^ what he said. My Z6 only tuned in at 129whp. and that was with bolt ons and a Skunk 2 intake manifold. head work and valve train and Cam and getting my compression to atleast 10.5:1 would go somewhere in the 150-160 range. with a great tune. Cant forget the fuel pump to supply!!! =]

:thumb:
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By Eg6H2D
- Thu Mar 31, 2011 8:12 pm #247433
SL93ex wrote:
dbrooks wrote:what i would do instead of having the head work done, is look on craigslist or a local forum for an already ported & polished head. when you look at it, make sure everythings in good shape. that's what i did when i was going to do a mini-me and i got a super good deal.


I'll do the port/chamber work myself... open up the short radius/divider area a little, smooth the guide boss, taper the guide, smooth the seat area... etc. Old school stuff :) I'm only going to have the head resurfaced at most. I definately don't want to go much more than 10:1. And I definately want to avoid any lengthy tuning sessions... As it is, the tune will cost as much as the build.

And again, I'm only looking for 150hp at the crank, so 120hp at the wheels sounds about right.


Lengthy tune? who is doing your tuning and on what engine management? took my car about an hour.. with a change of plugs in between. :lol:

By SL93ex
- Fri Apr 01, 2011 7:30 am #247566 Well you guys have convinced me that a 25hp gain isn't realistic without a major investment in time and money.

So... I'm going to just take what I can get and be happy with a fresh top end.

Thanks for your input.

By AutoXCivic
- Fri Apr 01, 2011 5:04 pm #247616
SL93ex wrote:Well you guys have convinced me that a 25hp gain isn't realistic without a major investment in time and money.

So... I'm going to just take what I can get and be happy with a fresh top end.

Thanks for your input.


You can get 120 whp very easily. My d15b7/z6 mini me was 124 whp without a tune (or cam). Since you are freshening up the head anyway, mill it, get a decent cam + springs/retainers. With a tune you should hit 120 whp with no problem. My engine was a 1.5 L running ~ 10.2:1 CR.

I think most people were not taking into account the fact that you were looking for 150 BHP and not 150 WHP which would take a significat investment to get done on an N/A d-series.
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