[/B]When building the engine there wasn't anything in the cylinders or new pistons that would seem to create a hot spot. All cylinders were bored and honed. Also, there shouldn't be a restriction in the oiling system. The block was ultrasonically cleaned. The coolant system was bled for a long time until all of the bubbles were out using an "overfill" funnel system.

The fuel is the only thing I'm not positive about in the last tune. I SHOULD have had 93 fuel in the tank like I always do, but there could have been a mixup at pump (unlikely but possible) where I put in 87. That's a low chance, but is still there. This is something also that will be tested at the next trip when I go in with good gas and possibly test with race gas to cancel that out.

 

Thats good, its just what come to mind... If you did have 87 in there then that would definatly explain it. Hopefully thats what it is... When you heading back to the dyno ?

 

Its either your octane rating is to low or the engines detonation resistance has been lowered some how.

 

not if the flex collapsed internally.

 

Rich- A lower octane would explain the "new" detonation on the second pass, but it wouldn't necessary explain why the car isn't making power proportionate to boost, would it?? The car reacted the same way the second time on the dyno as the first (just at a lower timing). Also, I'm working with TurboLS to get some JG303 cams reground to open up the head (incase that may be an issue). So after I get those installed with valvetrain, then I can start looking to go back.

As long as the cash is there after (won't be considered a retune since my components are so different and it will be full price). The shop owner was nice enough to let me leave last time to fix my issue and come back without a charge. I doubt I'll be that lucky again.

kyden- you're right, if it collapsed, then this would be a big issue as it wouldn't let the turbo breathe. But I just built this one, so all is well. Thanks for the idea tho

 

It could do but it all comes down to how potent both batches of fuel are compared to one on other. e.g. say we have a engine running at 0psi and is making 200hp on 90 octane fuel that has a slight detonation issue. We then add water (not meth) to increase the octane (or slow the burn rate) of the fuel but now we only make 190hp but we have a octane rating of 93. We then decide to ditch that idea and find some proper 93 octane fuel and hit the dyno again, we now make 210hp. Basically theres more to it than just octane, it also down to what else is in the actually fuel. You'll probably find that some of the top end pump fuels are designed for power in mind, but i don't know your fuel, so its more or less impossible to confirm & if the difference would be something you'd notice. I know our 99 Shell V power over here was designed for power in mind but then again i'm not sure how much power you'd gain in running it over the cheaper stuff you can buy as i've never tested or known anyone test them.

That was kind of the shop owner to do that... very kind indeed.

 

Yeah, I understand what you're saying about the fuel. That is a big possibility for why the car knocked under load on the second tune (and not on the first). It's something that I'll be looking to eliminate this next go around.

Thanks again for all your help! I really appreciate it!

 

No problem man, i wish you the best of luck

 

bad dizzy if their is no boost leaks and timing is on. My car had a issue like this and i replaced the dizzy!

 

Thanks man! Any more info is much appreicated (motor, power levels/psi, etc).

I just ordered a OBD2-OBD1 dizzy harness so that I can use a newer dizzy with hopefully less miles (and less issues). I'm sourcing one right now and I will let everyone know how it goes. I'm also waiting on my cams and such too. It'd be nice to get back to the dyno within a month or two.

 

The problem is a weak spark wouldn't cause the engine to detonate. It would do the opposite if anything...

 

The detonation only happened on the second tune, so I'm thinking it was something easy like bad gas (or a mistake on my part to put in a lower octane). I won't know this until I go back, but that's what I'm thinking.

BUT, the problem with power/psi ratio was there on both runs.

 

I see what your saying... Give a new distributor a shot anyway.

 

Yeah, I planned to pick up a dizzy and either take it with me or just install it before I go. I'm thinking I might just take it with me so that I can see a before/after and maybe have dyno sheets to HOPEFULLY show how much power I'd be picking up. LOL

Thanks for your help Rich!

 

Thats a good idea, it only takes 2 minutes to swap them around. I had a look at your screen shot btw. Everything what i could see looked nice and smooth like its suppose to. Who ever's doing your tuning is doing it right

 

Yeah, he's a really reputable tuner. He's on here sometimes, but I don't want to throw out his name because I don't want this to look as if it was his fault. It's definitely something amiss, and I'm hoping it's just the dizzy not working properly when increasing the boost.

 

Thats perfectly understandable, i would do the same, specially on this forum lol. Its either your best friend or your worst enemy if your a tuner or engine builder. Out of interest are from east or west USA ? I get the impression your up early from the time i normally see your online (mid day over here).

 

I'm in Texas on the coast. I get to work about 7am over here (CST), so that probably seems really early.

 

OK. Just a little update....

I sourced a JDM B20 dizzy yesterday that should make it's way to me soon. It supposedly came off a swap that was ordered, but the guy was going to OBD0, so he didn't need it. It should have low mileage and give me the best chance of having a tip-top OEM dizzy for the purpose of my "test".

To use this OBD2 dizzy, I've also got an MSD conversion harness coming. I figured this would be a good idea as OBD1 distributors are harder to find and usually have higher mileage (greater risk of it being bad).

Anyways, hopefully this will help solve the issue of my mysterious power search. After I get my cams and whatnot I'll install them and see about getting a tune. I'll keep the thread updated.

 

Good luck man !!

 

A little update for those listening....

I got my JDM dizzy in the mail last night....BUT the cap was smashed

It's not that bad though because I had a couple of other caps. The inside of it looks mint though, so I'm hopeful that this will help my power issue. However, I've also got a question.

Would this distributor be safe to use on the street until I get my new cams and valvetrain installed (tune after that)?? I don't see that it would throw off my AFR's by much since it's just a stronger spark (hopefully). My tune is set up pretty safe right now (about 5* timing pulled from last tune), so I don't think I'll have any issues with that. I just want to see what you guys think.

 

My only concern with that would be getting the ignition timing set by timing light exactly as the old distributor was set.

 

Yeah, I did that last night when I installed the new distributor. Locked the timing at 16* and set it with my timing light.

 

The car seems to be running fine with the new distributor. I can't really feel any power difference with nothing else changed but the dizzy. Hopefully it's something that would prove itself on the dyno while turning up the boost.

All the AFR's and everything are holding fine, so I know I was good there. After I do cams, valvetrain, and probably an intake manifold I'll be going back to the tuner to see how it does. It could be a while, but it will get done

 

Good stuff man, never rush, you'll get there