shanepa2001

ok i just wana ask a question here i was reading around on the internet and i seen this posted. just want to justify it before i look further into it. they r claiming that a guy ran 13-15 psi of boost driven daily for 7 months with ALL stock internals in a 16 by the use of a "compression lowering head gasket" any info on this would be nice want to know if it is a recomended way of lowering compression and maybe of draw backs of using it to do that. any ifo would be apreciated. the reason i ask is because i am running a jdm d15b and want to drop the compression and up the boost but am having trouble looking for replacment internals and cant get a new motor aytime soon

the post was on this website btw
http://www.turbo-kits.com/d16a_vtec_dyno.html

EG6 Poe

Stock d16 or b16 cylinder walls and pistons are good for only 9-10PSI with PROPER TUNING. Anything above that and you'll go KABLEWY!!

shanepa2001

its not the first time i herd of using this for lowering compression and boosting more. just wana see a real opinion on it

.Radical_Edward.

Stock D15 and D16's can handle up to 15psi on a small turbo at stock compression with ARP Head Studs and Rod Bolts. I'm not sure for how long though. Lowering compression can help, but a good tune is always important.

It's not how many lbs that makes the difference, it's how much power it's making that determines if it's going to blow. Stock D15/D16's can take up to 250 whp on stock internals provided a good tune and ARP Head Studs.

200-215whp on completely stock internals provided a decent tune.

I boosted my D15B7 from 7 to up to 12psi for almost a year with no problems. Then after the mini-me swap I boosted that at 8psi for another month before it sold. No problems at all. Completely stock internals.

cambopheonix56

I suppose it all depends on the turbo size. I am sure 10 psi on a t25 is nothing. I saw someguy with a b16 running 15 psi stock internals with 385whp. I don't remember what turbo tho.

shanepa2001

i think u misunderstoud what i am asking. will the "extra boost" over say the max (8-10) recomended just replace the comression lost by increasing the size of the head gasket?? therfore getting the same WHP with 13-15psi at 8.8 comression compared to 8-10psi at stock 9.2 comrpression... does anyone understand what i mean??

92spoolineghatch

i think on the d15 you would be safer and better off going with lower boost and the factory honda gasket. i have had a problem with those cometic usa gaskets letting boost blow into the water jackets due to the weak head studs. i went back to a oem honda gasket and the stock studs. and i have no probs. the cometic gasket lasted me 2 weeks and blew out. my freind also had a problem with his as soon as 10 lbs was exceeded. hey by the way do you ever go to the races down there on holstein i see your from PHILLY thats were im from

shanepa2001

hella ya im down there every weekend lol i havent ran down there yet tho wit my hatchback but i was down there all last weekend watchin u might recoginze me if u seen me

EG6 Poe

13PSI on 8.8:1 comp. is gonna yield more power than 9PSI at 9.2 comp. with the same tune. It's all in tuning. Dude, just be safe and keep it around 8PSI at your comp. ratio now.

.Radical_Edward.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by shanepa2001 &raquo;</TD></TR><TR><TD CLASS="quote">i think u misunderstoud what i am asking. will the "extra boost" over say the max (8-10) recomended just replace the comression lost by increasing the size of the head gasket?? therfore getting the same WHP with 13-15psi at 8.8 comression compared to 8-10psi at stock 9.2 comrpression... does anyone understand what i mean??</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG6 Poe &raquo;</TD></TR><TR><TD CLASS="quote">13PSI on 8.8:1 comp. is gonna yield more power than 9PSI at 9.2 comp. with the same tune. It's all in tuning. Dude, just be safe and keep it around 8PSI at your comp. ratio now.</TD></TR></TABLE>

agreed

shanepa2001

well lol i wana go faster but am on he tight budget wana get some info on this just curious about it wondering if its a good idea or waste and a high risk

btw this setup is assuming arp headstuds and cam tuning and ecu tuning etc.. but on all stock internals with minor bolt ons and 3" exhaust

.Radical_Edward.

On stock internals, no more then 10psi with a good tune considering if you don't change anything at all.

92spoolineghatch

well next time im up that way i might have to get up witch ya and we can give our single cams a run. but i just think your better off with the stock gasket. those cometics are junk. youd be better off with a block gaurd. i run this kid down here and he has a 92 hatch just like mine. he has a b18b with a full turbonetics kit on it and he runs 10 lbs. and i literally stomp him into the ground. its not the boost. its the tuning and the fuel that makes the car make power. i run 320 injectors a 10/1 fmu and set my regulator at 42 lbs and the thing runs 13.3 in the quarter people cant believe its a single cam with only 7.5 lbs but its fast. the only thing i dont like is the fact that when im idleing down it backfires a little. i think its because the fmu dont back off fast enough and it still dumps a lil fuel making it run rich but i have been running it for three months and the compression checks still come out around 180 in all cylinders

.Radical_Edward.

I don't have the D-series anymore. I went LSVTEC

shanepa2001

ok well say i did keep the stock head gasket, what head gasket would fit this engine right a d16z6 gasket? because i want to pull it off and relace it after i get a set of ARP's for it. i am pretty sure the d15b is a VX core p08 head....??? so i would use VX sized studs or z6 for that also..??

Blazin Civic

I ran 12psi daily on a greddy kit on my jdm d15b...all stock motor except S2 IM. If I had a 3 bar i would have felt comfortable doing 15 every now and then.

ev13lf

lowering the compression ratio gives you more of a cushion against detonation by lowering cylinder pressures, and yes cylinder pressure does have lot to do with boost numbers. just be careful with the tune and you should be ok, unless of course you blow up your motor. good luck.

MKIIISupraBeef

Lowering compression will raise the detonation threshold meaning you can run more boost, yay... however using a thicker headgasket to do so will not deliever the results you expect. By increasing the thickness of the gasket, you increase area that preignition/detonation (of anykind) will damage. So the CR drop you get will only have a fraction of its expected usefullness. For example going from a 9.6:1 to a 9.2:1 through use of a gasket, we be more like raising the detonation damage threshold like a .1 or so.. to like a 9.5:1... Overall not worth it in my oppinion, unless of coarse you milled the deck or head and you need to get height back.. then thicker head gaskets are worthwhile.

DannyDeuce

PSI don't matter..........its all about horsepower.

As mentioned above.......a stock D series can handle 200-215 whp(max), and you can get this horsepower at 8psi or 10psi or 15psi. It all depends on the turbo and the tune.

DAN

cambopheonix56

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DannyDeuce &raquo;</TD></TR><TR><TD CLASS="quote">PSI don't matter..........its all about horsepower.

As mentioned above.......a stock D series can handle 200-215 whp(max), and you can get this horsepower at 8psi or 10psi or 15psi. It all depends on the turbo and the tune.

DAN</TD></TR></TABLE>

Thats what I mean, everyones talking about max psi blablabla. If you had a small enough turbo you could run 50psi as long as the hp was not exceeding the limit of the engine, ~215 whp.

.Radical_Edward.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ev13lf &raquo;</TD></TR><TR><TD CLASS="quote">and yes cylinder pressure does have lot to do with boost numbers. </TD></TR></TABLE>

It plays a factor, however is not important as you could be running X amount of psi, but only be making a certain amount of power, be under a given engine's stock power limt and still not detonate(for a period of time, of course).
If you have the correct amount of fuel at any given psi to compensate for the increase in air that's being pushed into the engine, then the engine still will not blow up.

I've known people who have put very small turbo's on stock D's and ran 15-17psi on stock internals with very precise tunning. Not one of their engines popped within 8 months. You can't just say a D engine can't take a certain amount of psi. If you know what you're doing a D can safely handle 15 psi daily from just about any turbo under 60. A/R with ARP headstuds and tunning alone.

I should know, I ran a turbo D and had the same engine the entire time, without blowing it up. From 8-12psi continuously for over a year. On stock internals. The only problem I ever had was all 8 exhaust valved got toasted after 6 months. That was all because of timing. Not x amount of PSI.

shanepa2001

ok so let me get this straight then i think i understand alot more. pretty much, its all in the tune? if u have a very good tuner dyno tune your car then achieve max HP at a good PSI of boost safley?

schardbody

make sure you have a good street tune. most tune for WOT, which is not close to the same as everyday driving. psi and hp numbers that the D can handle varies alot depending on condition of motor, parts used, and tune. boost always (ALWAYS) accelerates wear, no matter what, so a dying motor isnt going to hold nearly as much power as a fresh built bottom end stock internals or not. if you cant afford to buy a new motor anytime soon, as you say, going nuts w/ the boost and tune isnt a good idea. make the tuner realize that power is second to reliability, and you should be ok.

shanepa2001

will do. i am running a jdm D15b vtec so i the whole reason i even started this thread was because of the difficulty to find new internals for it and the fact that i want some more power out of it. in my case, yes reliabilty is #1 , more important than whp right now. im gona boost it at 10psi with a dyno tune and see how it works out. by the way it looks im gona take everyones advice with the head gasket idea and stick with OEM. il just pick up a z6 and rebuild it to hadle higher boost levels and more whp. because of the availibility of parts. i am a machinist so i have access to a CNC Mill and CNC lathe, along with many other tools and machines to help me. was even thinkin bout a port and polish job on the d15b head for some better flow while i build the z6. i really appreciate everyones input on this topic it helped me alot. so it can be agreed that this is my safest, most reliable option?

thank you
shane

schardbody

if you want to stay OEM and drop compression a little go w/ a d15b2 headgasket. its .048". Honda should have them in stock. and there are internals available for the D15b, just gotta know where to look.