When my engine blew, I took off the turbos and didnt even bother to look. I'm afraid to right now. Its been about 2 months. I will know soon enough if i have to upgrade to BNRs

 

Hmm boy did the builder lie to you then. So you had S5 T2 rotors instead of FD rotors? Actually thats not going to safeguard anything since S5 T2 rotors and FD rotors have the same compression. Thats right, they both have 9:1 compression. S4 T2 rotors are the only turbo rotors in 13B's that have lower compression which is 8.5:1.

 

Maybe they were S4 T2 rotors then. I couldn't remember offhand - I wasn't the one who had the engine built. The previous owner (AgentSpeed) had the engine rebuilt by Bryan at BNR Supercars.

 

Bryan is a standup guy, no worries with your engine builder.

 

Sorry about your misfortune, I just recently noticed this issue with the stock map sensor after my dyno pulls.

Almost every run was in the wrong P row above 13psi. Time to re-calibrate the map sensor

 

Just had the engine compression tested at Marvelspeed.

Front rotor: 8.0, 8.2, 8.0
Rear rotor: 0.0, 0.0, 8.2

What a bummer. It looks like I had wonderful compression up until I lost my engine, especially for the S4 TII rotors.

I found out what caused the overboost. A rubber vacuum cap split beside the wastegate vacuum line and allowed the engine to overboost.

Now I'm looking at rebuilding. Who are the top engine builders these days?

 

Yup, 8s are very good. That really really sucks that a damn cheap rubber vacuum cap caused you to lose a seal .

Top engine builders? Of course I'm going to say steve over at Gotham, but then I'm biased, lol. The guys over at RP build strong motors as well. You're lucky, you have two great great choices right in your own backyard!

 

Hey Rich, could you get on AIM? I have some questions about Gotham for ya.

 

hey man i think i did the same thing to my motor it has the same symptoms that you are describing, and now i am looking into where and how much its gonna cost to rebiuld it? if you have any suggestion iam all ears

 

Man what happened?!?!?!?!?!

Was 15 psi and 385rwhp not enough???

This makes me sad...

 

huh?

the stock sensor is accurate to about 1 bar (14.5)...above that, it's a crap shoot...ask Steve Kan, BDC, or any knowledgeable tuner

furthermore, BDC always recommends running at a mix of 100 octane and 93 premium above 14 psi

 

i dont understand what u guys are meaning by stock map sensor and like a 3 bar map sensor so if u can explain it to me without getting rude comments that would make my day

 

there are different levels of MAP (manifold absolute pressure) sensors: 1bar, 2 bar, 3bar, 4bar, 5bar, etc. and 1 bar =14.5psi. with map sensors, the first bar is always for vacuum. SO:
a 1 bar map sensor reads vacuum; 0-30inHg
a 2 bar map sensor reads vacuum and 1bar of boost; 30inHg-0-14.5psi
a 3 bar map sensor reads vacuum and 2bar of boost; 30inHg-0-29psi
a 4 bar map sensor reads vacuum and 3bar of boost; 30inHg-0-43.5psi
etc.

stock MAP sensor reads a little over 2 bar. supposedly its not very accurate over 13-14psi. maybe people just think that because its a 2bar map sensor and it only reads to 14.5psi? (thats just a guess, i'm not really sure about that)

there guy, i hope i made your day.

 

I lost my engine with a similar failure. My wastegate hose split and I overboosted past the point my fuel pump would support.

Now my wastegate line is a threaded 4AN connection on both sides so it cant pop off and it is an insulated line that is rated at 1300F.

I also switched to a 3bar (like a 5 minute job), and switched to dual fuel pumps. This did not stop me from blowing the engine 1500 miles later with some bad igl/igt settings in my p10/15 n12/18 area - a downshift was all it took. I have a much more conservative map now and have been boosting at 16 for a couple thousand miles.

The thing I always wondered about was why dont we just set the igl/igt really retarded above the max boost we want to run? That way the engine overboosts and it just falls on it face but doesnt detonate.

 

The difference is about relative pressure and absolute pressure.

At sea level, the weight of air on the earth produces 1 bar (14.5psi) everywhere. So this is 1 bar absolute pressure. If you pressurize the air further, like in a boosted engine, and produce "1 bar" of boost you're adding to that base 1 bar. So a 2 bar map sensor can only handle one bar of boost. A 3 bar map sensor can handle 2 bar of boost (29 psi).

Dave

 

yeah guy check out my post above

 

Sorry to hear the mishap with your car. Hope you get it back together soon.

Bryan@BNR

 

OK, I'm officially scared...lol My pfc goes upto 1.13 now, before when I had a high flow cat it went to 1.10 (now I have a res midpipe) My boost gauge is an autometer and it went up to 20psi. Which one do I trust?

 

Do you have a three bar map sensor? 1 kg/cm^2 (on the pfc commander) is 14.2 psi, so 1.13 is about 16.2 psi. If you don't have one, get it immediately.

I say get rid of the shitty autometer gauge, the one I had many years ago read consistently 2 psi too high.

 

Yeah, after reading all this I have decided to get a 3bar map sensor. But My pfc should be correct up to 1.15? So since I haven't passed that point yet I haven't really been over boosting?

 

"The most expensive engine is a cheap rebuild-that fails!"
No shortcuts here-
www.rotorsportsracing.com"

 

Correct, but you're awfully close. I'm surprised Banzai let your car leave with the stock map sensor after the 500r install......

 

Not sure where you're going with this post. Are you saying the thread starter had a shitty motor

 

Well, the highest that I was hitting on the pfc when we tuned it was 1.08. When it got a little colder out, I started hitting 1.10. When I put the res midpipe and it's cold out, I hit 1.13. 3bar map sensors are only like $75, and easy to install right? This winter my car is getting the works, so by next summer all the kinks will be out of it.

 

GM 3 bars are pretty cheap, the install is fairly easy, but I see them get frequently installed in a half-assed manner, where the wires are crimped into the connector. Mine was like that for awhile and it caused all sorts of crazy problems (like reading max bosot while cruising and the car would suddenly flood and shut down) until my bud ccarlisi turned me onto a better method of install. Your best bet is to purchase the proper female connector with pigtail that allows you to solder into your harness. Also, I recommend looking into the apex'i 3 bar sensor that is designed to work in conjunction with the power fc. It supposedly corrects for elevation differences if i remember correctly, which is a nice bonus.

In the meantime I recommend turning your boost controller down until you're seeing around 1.00 on the commander. Your TiAL 44mm should be able to handle any potential creep