Hey everyone i have a couple questions about boosting my d15b7
I have a 1993 Civic Dx with a d15b7 138k on the motor. The motor is super healthy bone stock.
Will I be Reliable?
What size head gasket should I look into
I want to go with a god speed T3/T4 turbo kit
Run a thicker head gasket
Arp Head Studs

My goals for the Motor
Is to run about 195-200 HP
about 7-8Ibs of boost
On a Good Tune
And be reliable

I just want the car to have some more pick up to pull me threw the corners
thanks guys appreciate the help.

 

I've seen d16y8 and z6's in the 225whp area stock and daily driven. It's not hard but I would stay away from eBay turbo kits. You can probably do a junk yard kit that will be more reliable around the same price.

Try www.homemadeturbo.com

 

Should be fine at low boost levels. Mine held up for a little while at 13 psi before spitting the rods out. Precision SC34

 

yes 225 is the safe limit for most d series, the limiting factor being the stock connecting rods... they are as thin as a pencil and notoriously weak


do not get that turbo kit. it's a cheap Chinese kit produced in bulk and quality is nonexistent. the turbos fail, sometimes on first startup, sometimes 500 miles later, and some don't fail until 10-15k miles. some don't fail at all (this is very rare) it's not worth the investment just from the standpoint of the turbo that comes with the kit


the manifolds crack, all of them.. it's not a matter of if but when, they crack at the turbine flange and the wastegate flange. I've seen situations where the entire wastegate flange snaps off sending your wastegate flying down the road behind your car.. (this also prevents a hazard to drivers behind you... and any damage or accidents resulting from that wastegate flying off your car at high speed, effectively turning into a middle or shrapnel, you'd be financially liable for)

as far as the other components... the wastegates fail rapidly (seal in the bottom housing around the valve shaft fails, allowing hot exhaust gasses into the wastegate, melting and destroying the diaphragm and any other heat sensitive parts) and they leak (around the seal i just mentioned and the tops leak due to poor machine work, the two halves don't meet evenly and the diaphragm doesn't seat, allowing leaks, also sometimes the wastegates show up new with torn or defective diaphragms and the spring rate they say it has is almost always wrong, meaning you don't know what base boost pressure is till you throw the car on the dyno),


the blow off valves leak and more often than not get stuck and seize. they too come with poor quality diaphragms and most of the time the spring in the valve is too stiff to allow the valve to open, even with the adjuster fully backed off or removed, resulting in compressor surge. luckily most come with two springs inside, everyone normally has to remove the stiffer spring and use the softer one to allow for proper operation (dealt with this with a car I bought in Indiana and drove it back, did nothing but flutter and surge with both springs and a loosened adjuster, took one spring out and it still did it, this was on a stock turbo SR20DET at 14psi, valve was on the hot pipe too... luckily I packed a quality name brand blow off valve in my bag (and other parts just incase, the TSA got so confused xraying my bag lol) and swapped it out at a gas station, adjusted it and bam.. no more surge and flutter

the intercooler piping is made from a very low grade aluminum alloy and is very prone to becoming brittle, cracking or deforming over time, especially if you over tighten the clamps or the piping sees a lot of vibrations


speaking of which, the clamps and the couplers included with the kit are ****. couplers aren't true silicone, the rip and tear.. the clamps are the same way, half the time they break or strip when you tighten them down


the intercoolers used are very cheap, inefficient cores and the end tanks don't allow for even airflow through the core, this means higher IATs, reduced power per lb of boost and a lower detonation threshold.


take it from people with experience here, forget the eBay kit (turbo is wayyy too large for your low power levels anyways) and piece together your own from quality parts from quality companies. you can also look in the classifieds here and find everything you need to piece a kit together using both new and used parts, the sellers on here are usually very honest and have very reasonable asking prices for their stuff. the classified for the site sponsors are also a good place to look. these sponsors support our site and in return offer special deals to Honda-Tech members so look there as well.


or you can get everything from a complete kit to just a manifold and downpipe, or just a turbo from companies like RC Autoworks, GO Autoworks, etc.

the ARP headstuds are a must to keep the head properly sealed and seated, you will also need a new headgasket when you install the studs. there's no need for a thicker gasket as lowering the compression won't help you here, you'll only make lless power per pound of boost as you're still limited by the stock rods, stick with an OEM headgasket... they've been proven to withstand over 800hp


you also don't mention anything about fuel/engine management and tuning you CANNOT just slap on a kit and go, you need some way to tune the car... and no an FMU does not count



at the very least you need the following


Walbro 255lph fuel pump


larger injectors (DSM 440s are fine for your power goals)



1 step colder spark plugs (this is to prevent pre-ignition/detonation as a hotter spark plug (like the OEM units) will run too hot and cause detonation


a chipped OBD1 ecu, a p28 or p72 (for vtec motors) or a p06 (for non-vtec motors, can always be upgraded to a p28 if you ever decide to go with a vtec head/motor, the process is very simple) will work. you can use numerous software options to control and tune the ecu like crome, crome gold, Neptune, or Hondata S300

If you plan on running more than 10psi you'll need a different map sensor as the stock one won't read above 10psi... many companies make OEM replacement 3bar sensors or you can go with the cheaper gm 3bar


you also need some form of boost control if you want to run more boost than what the spring in the wastegate is set for. this can be as simple as a manual unit that goes inline to the pressure signal to the wastegate(you turn the **** to raise or lower boost levels) or you can use a gm boost control solenoid or a Mac solenoid, these get hooked up to the ecu and then the ecu will control boost levels (this method has to be tuned just like fueling and timing)


you need a few basic gauges as well


a wideband air fuel gauge to keep track of what the motor is doing, also to aid in tuning the car, as well as being able to see if something is wrong, as the air fuel ratio values will change from when it was tuned

a boost gauge to make sure you're running the pressure you want and that you don't have any creep issues, this also helps you notice a problem because sometimes boost levels will drop


an oil pressure gauge, this is essential as oil pressure is what keeps the motor running, turbo cars tend to see a lot of abuse and higher power levels stress the bottom end more, especially on d series motors


any other gauges are your personal preference but those are the three I deem as mandatory on any boosted vehicle


this covers the basics, I strongly suggest you read the FAQs stickied at the top of this forum, it contains all the info and basics of properly turbocharging a Honda. that compiled research will help you a lot

if you have any doubts about your ability to install the kit please contact a reputable local shop and have them install it

and above all, have an experienced professional tune the car

 

I wouldn't trust a D15B7 at 225 HP. The rods are just too weak.

 

the one advantage with the d15b7 is that it has a very low compression ratio in stock form, this will allow a little wiggle room as far as elevated cylinder pressures go but the rods are still the weak link (i think the d15b7 has some of the thinnest rods out of all d series motors IIRC)

also with it being non-vtec means it will take more boost to make the power you want, couple that with a poorly designed intake manifold and a very very poor cam design (cam was designed for maximum economy, not power and performance) and you're looking at a highly strung motor just waiting to commit suicide

I suggest you at least do a head swap or find a "performance" cam to help you with your power goals.