dispute help settle will thicker head gasket make reliability and slow turbo spool - Honda Prelude Forum

ziggity · 01-29-2003, 11:45 PM

ok i am getting my turbo tuned by a local tuner (very reputable at h-t) vaportrail i spoke with him about me putting a thicker .057 cometic head gasket and J&S safeguard with a hondata s200 tuned by him

here is what he said lowering the CR on the stock pistons is going to do NOTHING for me in the case of reliability because if it is tuned right i wont need it and the J&S safeguard he says have never seen "save" an engine on a properly tuned car

so i got the safeguard and i will be installing it regardless vecasue i want to be safe just in case but the head gasket is what i am wondering is should i do or dont indtall the HG it wont be that much extra work and i want to be as near to bulletproof as possible i understand his point that i will lose power in vaccum and that wont be so bad (maybe better gas mileage) but how much power are we talking? and will lowering the CR make the turbo spool that much slower? like how much? and i just need some feedback from some experienced people before i decide what to do i am taking the IM off for a hondata gasket regardless and i have ARP head studs too (dont ask why) what should i do here

Obsidian7 · 01-30-2003, 08:58 AM

I wouldn't think of a thicker head gasket as something that adds "reliability". It lowers your compression ratio, so that you can run more boost with less chance of detontation. If you just ran the same amount of boost with or without the thicker head gasket, then the gasket would actually cause you to lose power.. so I guess that would add reliability

Unless you are planning to run higher amounts of boost (over 7psi regularly), I wouldn't swap the headgasket.. see how it runs with the stock CR. If you decide you want more from your engine, then consider the gasket (or maybe some internals?).

Some Hondata tuners are so anti-J&S it's amazing. Yes, in a *perfect* world, a 100% properly tuned Hondata system would *never* detonate and girls will flock to your car after every 10 second 1/4 mile pass.

In my no-so-perfect world, there are hot days, there is bad fuel.. there are so many conditions, that I know my tuner and I could never possibly take every possible scenario into account. Sure, you can dumb down the Hondata tune a bit and make the car slower, but who wants to do that?

When my J&S would "act up" and pull timing, it was always easy to figure out why:
- "Well, it is *really* hot out today.. almost 100 degrees"
- "I know to never by gas at that station again..."
- "Maybe I should back off the timing a bit in that part of the map"

On a side note: What type of dyno does your tuner use?

ziggity · 01-30-2003, 11:21 AM

check him out at www.vapor-trail.net

what i was thinking is that i will have less pressure on the ringlands with lower compression and that i could prolong the life of my engine by installing it my ultimate goal (maybe unreachable

) is to have a daily driver that is reliable on the most part and i want my stock pistons to hold up for a while that is why i have so many safety devices (i have other things as well as the J&S) but if the inevitable occours too soon i will rebuild the engine to stock spec and sell the car for a WRX Sti or a EVO VII whatever comes first

i am not trying to make bookoo hp here i would be happy with 240

ziggity · 01-30-2003, 11:24 AM

and how about sppol up time this should be affected but by how much i know quualude has this HG i wonder if hell chime in by the way i have a .63 a/r turbine and a 54 trim compressor t3/t04e

Obsidian7 · 01-30-2003, 11:51 AM

The dyno chart on their website of the JRSC Prelude is *scary*.. that's far too lean for my tastes! From 3250-6500 rpm.. the A/F ratio should be at least 1 full point richer.

It also shows on their website that they have a DynoJet dyno. I may be wrong, but from what I have seen, the way people tune timing on a DynoJet is to advance the timing until there are no more gains... then they call it "done".

However, on a Mustang dyno, you can look at the dyno run in many different ways.. one of them will actually show a detonation event in the graph (detontation would show up as a brief moment of zero or negative acceleration).

Obsidian7 · 01-30-2003, 11:52 AM

I know that the turbo would spool up slower if you ran a lower CR, but I couldn't tell you how much slower...

schwett · 01-30-2003, 03:40 PM

either way the car needs careful tuning of the timing map in order to prevent detonation. you can't just lower the cr half a point and say, "done, imma run stock timing."

however : it will be easier to get a car with a lower compression ratio to run safely. if you're running 7psi though, on decent gas, i would suggest you leave the headgasket alone, make sure the timing maps are tuned very carefully and convservatively, and get the j&s. it's much cheaper than a new motor. (easier to install too!)

i am going to assume that dyno on his website is just a random sample of the wideband in action... because if he's suggesting that is a properly tuned car, run far, far, far away. as already pointed out : WAY too lean. typical stock JRSC dyno.

ziggity · 01-30-2003, 05:21 PM

i am not convinced with the statement

detonation kills ringlands(well obviously it can but it isnt the only thing)

i believe that the ringlands are broken because of many reasons but first and foremost i think it is the pressure on the ringlands itself this is all assuming that the car is tuned properly AF ratio and timing maps

one example sagaprelude has boosted up to 11 psi with the rideal HG and has not blown yet i am not sure of the equation but i would guess that 8psi with a 10:1 would exert nearly the same amount of pressure on the ringlands as say 10 psi on a 9.0-9.3:1

i have absoultely no intentions of boosting past 8 even with the head gasket so i was thinking it would ultimately lower the pressure on the ringlands and finally yes it will be properly tuned ask around h-t he is a very smart tuner and people call him conservative

by the way i own a J&S and an oil cooler as well as catch can yada yada yada EVERYTHING to help prevent detonation

Obsidian7 · 01-30-2003, 11:12 PM

The reason detonation kills H22 ringlands is simple. The cylinder pressures created by a detonation event *FAR EXCEEDS* the "normal" (ha!) cylinder pressures you would see in a boosted H22.

Think about it... normally, the energy released from the burning of air & fuel is timed properly to push down on the pistion, providing power. With detonation, instead of using that energy for power, you are compressing it.. because the spark timing was too early, the mixture was too lean to provide a "controlled" burn, or in-cylinder temperatures were too high and caused the mixture to ignite early. The same energy that is normally used to send the pistion back down is now being squished by the pistion. Something has to give, and the ringlands are the weakest link.

You'd have to run *stupid* amounts of boost on a stock block to match the cylinder pressure of a single detonation event... You simply won't be running that kind of boost.

Assuming sane levels of boost (under 11psi), *any* situation you can think of that will destroy a ringland (running lean, incorrect timing, bad fuel, failed injector, etc.).. leads to a detonation/knock event.

Most of the blown JRSCed, turboed, or N20ed H22 motors here in this forum failed because of detonation. I don't think anyone can disprove that.

schwett · 01-30-2003, 11:16 PM

Quote:

Originally posted by Obsidian7
....Most of the blown JRSCed, turboed, or N20ed H22 motors here in this forum failed because of detonation. I don't think anyone can disprove that.

this is almost certainly true, and keep in mind :

some detonation can't be heard be even the most careful ear. experience and conservative tuning is the only choice besides a j&s on this motor.

Obsidian7 · 01-30-2003, 11:24 PM

Quote:

Originally posted by schwett

this is almost certainly true, and keep in mind :

some detonation can't be heard be even the most careful ear. experience and conservative tuning is the only choice besides a j&s on this motor.

Agreed! ..but I prefer:

"experience and conservative tuning is the only choice along with a j&s on this motor."

..but that's just me

Pok-gai · 01-31-2003, 11:35 AM

Quote:

Originally posted by Obsidian7
I wouldn't think of a thicker head gasket as something that adds "reliability". It lowers your compression ratio, so that you can run more boost with less chance of detontation. If you just ran the same amount of boost with or without the thicker head gasket, then the gasket would actually cause you to lose power.. so I guess that would add reliability

what about if i was going to run 6 psi on stock internals for a few months with block rebuild planned for summer? i was planning on getting a lower compression head gasket and an ems for tuning purposes...if i get it tuned carefully, would i really need the head gasket? originally i figured i would be safer with lower compression too, but if you say conservative tuning and some form of knock control (the ems is capable of this, correct?) then i may just stay with the stock gasket.

schwett · 01-31-2003, 11:47 AM

lots of people (most people) run 6-7 psi of boost on the stock headgasket. it just means you run less timing that you would with lower compression. i don't think lower compression means you can do away with good boost timing control, so you STILL need the ems/btc/j&s, whatever you decide to use, with or without the headgasket. my $.02, don't bother with the headgasket at <10psi of boost.

Quote:

Originally posted by Pok-gai

what about if i was going to run 6 psi on stock internals for a few months with block rebuild planned for summer? i was planning on getting a lower compression head gasket and an ems for tuning purposes...if i get it tuned carefully, would i really need the head gasket? originally i figured i would be safer with lower compression too, but if you say conservative tuning and some form of knock control (the ems is capable of this, correct?) then i may just stay with the stock gasket.

Quaalude · 01-31-2003, 05:39 PM

You really don't need a thicker headgasket for 7-8 psi but it will increase your margin of safety though. With a stock headgasket, you will make more power (at the same boost level) and the turbo should spool up faster because of the 10:1 compression ratio, but like Schwett said, you can't run as much timing as you would with a lower compression. I got the thicker headgasket because I needed a new gasket anyways since I took off the head (bent ex. valves) to send it to Portflow and I wanted to run more boost safely (currently running 8-9 psi). If you are going to use the stock headgasket and have a standalone, then just tune on the conservative side, have a device for knock control (J&S or AEM EMS), and run moderate levels of boost (7-8 psi).

BTW, I get full boost (9 psi) by 4000 rpm. The specs on the turbo are t3/t4e stage 3 w/0.63 a/r and 60 trim w/0.60 a/r.