The Sexy Grandma 15 day build

[1992awdlaser]

Im pretty sure Shep was running a bigger turbo.

Nope. He will be using a 47R when the car gets put back together though. He might have been running methanol also. I remember reading that he wasn't using an intercooler or radiator. Jake Montgomery got into the 8's also. I believe 8.6x's.

 

[Slippi84]

Nope. He will be using a 47R when the car gets put back together though. He might have been running methanol also. I remember reading that he wasn't using an intercooler or radiator. Jake Montgomery got into the 8's also. I believe 8.6x's.

That's right Jake M was 8's Jake(JHR) was 9.5

 

[fst91dsm]

And yes Shep was methanol only

 

[Snobordin8]

I just found this thread. Very nice car, I love that exhaust manifold. Good luck working out the bugs!

 

[tonster]

Cylinder compression was fine so the leak down test would be pointless.

You know what it is, its my Hondata heatshield intake manifold gasket, stupid Honda parts,

Cylinder pressures can vary from cylinder compression. As when you do a compression you are only measuring maximum compression. You might have 157psi it one cylinder but you might be losing pressure in that cylinder through the other phases of the motor during rotation. I would leak down it. You might be pushing air past somethings you would never think about it. It takes 10 seconds and it is another piece to the puzzle.

 

[SosaPerformance]

Cylinder pressures can vary from cylinder compression. As when you do a compression you are only measuring maximum compression. You might have 157psi it one cylinder but you might be losing pressure in that cylinder through the other phases of the motor during rotation. I would leak down it. You might be pushing air past somethings you would never think about it. It takes 10 seconds and it is another piece to the puzzle.

I agree with doing a leakdown since it would tell you a whole lot more than just a compression test. I had a similar situation although it was a B series honda but all the same priciples,we had it on the dyno and once we went up on boost (25+) it dropped torque like a rock and plateaud the HP. Checked everything out including compression test and all was fine but obviously we had a problem. Did a leakdown and 2 cylinders next to each other had more leakdown than the other 2 and no air coming from intake or dipstick so valves seemed to be sealing and no leakage past rings hence the good compression numbers. It ended up being the headgasket was the culprit and at high boost would actually lift head and leak past gasket resulting in lost compression and sudden tq drop and flat top end power unlike a honda on boost. The weird thing was we had no oil/water mixing so of course made it harder to detect,just keep in mind a HG will go in many diff ways. Switched out the HG and all was fine problem fixed. Not saying thats exactly your problem just saying compression test alone did not help me with tracking down the problem but your on the right track starting with that first. Cranking only would not cause the problem it needed cylinder pressures. I assume you are on an O-ringed head/block with L19s with the type of build you are doing considering boost/power levels you are expecting so like I said maybe not your problem. Just figured throwing that out there in case it might help. G/L

 

[hpexperts]

these guys are right i would do a leak down test it would only take a couple min to do it.

 

[fst91dsm]

Tell you guys what, ill do one tomorrow just because everyone is so pro leak down. Hell, i dont have anything else to do with it until my new manifold gets here anyways.

 

[SosaPerformance]

Tell you guys what, ill do one tomorrow just because everyone is so pro leak down. Hell, i dont have anything else to do with it until my new manifold gets here anyways.

Dont do it to please us. Just trying to help you figure out a problem.

 

[SICKBIRD]

Good luck with the build man. I'm with you though I think it may be something to do with the intake manifold not flowing enough or properly

 

[fst91dsm]

Dont do it to please us. Just trying to help you figure out a problem.

And i appreciate all the imput, really. But I know thats not it. But I will do it anyways. It only takes a couple of minutes.

 

[SosaPerformance]

How many lbs/min were you running at xx.xpsi on your logs. And also was it holding steady boost untill redline or when you let off.

 

[fst91dsm]

How many lbs/min were you running at xx.xpsi on your logs. And also was it holding steady boost untill redline or when you let off.

I didnt look up the lb per min, I guess i can look it up. Boost was steady and flat as can be.

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[SosaPerformance]

Pm'd you

 

[SosaPerformance]

I didnt look up the lb per min, I guess i can look it up. Boost was steady and flat as can be.

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Correct me if im reading it wrong but on your first graph that logs rpm,boost,A/F it looks like your a/f's are between 10.6-10.8 which is way too rich for the boost and timing you mentioned earlier in the thread which was not crazy advance. Not to mention your on c16. I fully understand that you get it in the ballpark untill reaching desired boost and then fine tune a/f and timing but it looks like it starts dropping torque when it goes rich. Peak torque is at 6200 so looks like your getting full boost by 5500 or so. Your drop at 7600-8400 could be the 272's are'nt cutting it for your combination which you already mentioned you were switching. I would put those 280's in there and lean it out and see where that gets you. Again Im sure you guys have been playing with diff. a/f's and what not but im just commenting on the specific graphs you posted up. G/L

 

[kris_stewart10]

Maybe your vtec isnt working???

or maybe VTEC kicked in so hard that it tore the engine to shreds with the amount of torque that his VTEC produced

 

[Slippi84]

Yeah he hit it on the head. Like I said in my other post you start with low timing and try and get your a/f in the right ball park. 10.6-10.8 is pump gas territory. On 16 running pump gas a/f ratios is even worse as the fuel is harder to break down which is good when you run a more edgy timing and a/f mixture but bad if your rich. Lean her to atleast 11.6-1 and then see how she reacts. To be honest with race gas you ultimately want to be in the 12.5-1 if you want to be real edgy and milk that thing for power

 

[Black_Bullet]

^ I agree.

So leaner AFRs, the 280 cams, jmfab mani , and much more boost and Im sure you will start getting the power levels you find acceptable , and then after that it'll just be a matter of drivetrain holding up I guess.

 

[marcmsj]

Agreed. That's pretty rich for c16. Lean her out and see what ya get.

 

[fst91dsm]

I agree with everyone. I feel changing the cams, the JM Fab Manifold and leaning her out will help. Plus turning up the boost. I wasnt tuning it so I didnt take notice of the AFR until after the fact. That has already been talked about and were going to lean her out a little to the 11.5-11.7 range to see how she reacts and go from there.

 

[91TSiGuy]

Alex, you definitely need to crank up the boost. Wait till we get that new intake out to you first so you have a manifold on there with a plenum large enough for the high rpm flow you'll need, but once installed get that turbo into it's efficiency range. From the 24psi to 39psi jump, that 15psi netted me 300hp. You'll see what I mean soon enough.

 

[fst91dsm]

Alex, you definitely need to crank up the boost. Wait till we get that new intake out to you first so you have a manifold on there with a plenum large enough for the high rpm flow you'll need, but once installed get that turbo into it's efficiency range. From the 24psi to 39psi jump, that 15psi netted me 300hp. You'll see what I mean soon enough.

Thanks Brent, I cant wait to get that manifold on there. I hope that, mixed with some other things will get the car where it needs to be. But only time will tell.

 

[PharmEcis]

I'm a little confused. I just spent the better part of an hour reading through this entire thread. In the beginning you bashed the Polk head but after what is evidently a timing belt tensioner failure, you end up calling the SBR head crappy compared to the Polk head. What gives?

Also, torque falling off like that looks just fine to me as your boost level remained solid. The only time torque stays flat is because of boost creep. If boost pressure stays consistent after peak torque, torque WILL fall and it can fall fast depending on a setup.

 

[fst91dsm]

I'm a little confused. I just spent the better part of an hour reading through this entire thread. In the beginning you bashed the Polk head but after what is evidently a timing belt tensioner failure, you end up calling the SBR head crappy compared to the Polk head. What gives?

Also, torque falling off like that looks just fine to me as your boost level remained solid. The only time torque stays flat is because of boost creep. If boost pressure stays consistent after peak torque, torque WILL fall and it can fall fast depending on a setup.

Im not exactly sure where you got your reasoning from... If you did read the thread then you would be able to awnser your own question. First, the Polk head was messed up as of last year, but we repaired the head, now it works the way it should. Second, the tensioner failing was never blamed on anything else but itself. The SBR head is still "crappy" and I have been trying to get the problem resolved with Slowboy. The reason I say that head is not as good or equal to the Polk head is this. One, it didnt flow as good, TQ dropped much faster and harder with that head. Second, the ports are far smaller in the SBR head (5mm width, 3mm height on the exhaust side)(1mm width, same height intake side) compared to the Polk head, as well as knife edging on the exhaust ports on the Polk head and none on the SBR head. And yes we have already decided that the TQ is falling slower then most DSM's, so that is a plus.

 

[PharmEcis]

You do realize that the size of the port doesn't dictate how well it flows right? Going bigger doesn't mean that it's better. Also, knife edging the exhaust divider in the head is just plain stupid. When you knife edge it, it becomes more prone to cracking and having the divider come apart at the edge. That means pieces of aluminum get to go through your turbo. Been there, done that.

I've seen these heads pick up more flow from just a very good valve job versus hogging the ports out. These heads really need an awesome valve job, bowl work and combustion chamber work. The ports themselves need some work, but should DEFINITELY not be where you are focusing most of your interest and work. They really just need a clean up.

For a drag car, you should be running at least 280s if not bigger in regards to cams. I bet most of your "felt" loss of power at the upper RPM band is due to your cam choice, especially if they are HKS 272s which really aren't that good.