TimZ

You are talking about valvetrain noise and not induction noise, right? How does the turbo affect that? I can hear my valvetrain just fine...

The timing marks on the chain do have to go back on the same teeth on the sprocket - it does effect the cam timing. If you didn't block the chain and tensioner with a proper tool then there is a 99% chance that the tensioner has fallen out and has wedged itself such that the chain won't go back. Hate to break the bad bad news, but if this is the case you're going to have to pull the front cover in order to put it back together correctly. Also, how much did you shave the head? This will also effect the cam timing - it can be pretty significant depending on how much material was removed.

Ya - the 1650 was with E85 - I was seeing north of 1800F with gas (Sunoco 94), which did make me a bit nervous. I run "straight" E85 -no mixing. Actually after having used it for a while now, the only thing that would make it not make sense to run would be if it weren't available. The EFI has been tuned to deliver the proper mixtures for E85 - you have to supply quite a bit more fuel - at max power I'm running an AFR of about 7.2, and at cruise I target around 11. Believe it or not 7.2 is acutally leaner than the max power rich numbers I've seen mentioned - which are usually around 6.95

No problem - after seeing that you guys were shooting for 1250F, I'm thinking that my mental model for high turbine inlet temps is different from yours - at this point I'm just happy to keep things under 1600... . ...btw - the last build did use custom Ferrea valves built to live under the temps I'm observing at the turbine inlet, and everything is ceramic coated.

The EBP sensors work great - I'm actually using one as my MAP sensor too. Just make sure to use a length of steel tubing to connect to the exhaust manifold pressure reference to isolate the sensor from the exhaust temps. ...So what was the Turbine Inlet Temp that occurred after making the mixture richer?

Lots of replies since the last time I checked... I agree - I believe that this is the reason for my elevated Turbine Inlet Temperatures (good point Tony), and why I showed the measured overlap and the TIP readings. This makes sense for my setup which has a relatively huge turbine housing and exhaust, but my understanding was that Jeff's setup uses a much smaller turbine housing for earlier spool. Given that my setup is resulting a bit less than 1:1 MAP/EBP until full boost and then about exactly 1:1, I can't see Jeff's setup having enough blowthrough for it to be the cause of his symptoms. For the EBP I'm using a Ford PowerStroke EBP sensor, connected to the turbine inlet pressure reference through about 8" of steel tubing. They have a measurement range of roughly 18inHg vacuum to 36psi pressure. Actually it works great for a MAP sensor too if you don't pull much vacuum. Do a search on PowerStroke EBP on eBay - you can usually find one for a decent price. As you mentioned I was referring to Turbine Inlet Temp as EGT, but as Jeff mentioned I wasn't trying to tune to a "magic number" temp as much as monitoring it and being a bit concerned. Incidentally, I suspect that my Turbine Inlet temp is considerably higher than the EGT at the exhaust port, judging from the condition of the combustion chamber and pistons at the last teardown. The temps I've seen at the turbine inlet would have left obvious evidence on the combustion chambers and pistons, but they looked just fine - not even any oil coking on the underside of the pistons. With this in mind I started with a generic and safe "max power rich" mixture as a baseline and then cautiously leaned out the mix a bit to make more power. I still didn't like seeing the Turbine Inlet Temp going north of 1700F, but it doesn't seem to be causing any actual problems. My main question was regarding the assertion that richer mixtures were the cause of the higher exhaust temps, which didn't make sense to me in this instance and in absence of some other factor. Also, were we just talking about going from 1250F to 1300, or were the temps going higher than that? I'm assuming you were asking "why" I run E85 - is that correct? More power, 105 octane, lower EGTs, MUCH cleaner burn, usually under $2.50/gallon. Since I've started running it, I REALLY don't want to go back to gasoline.

If you've already got the thing and it's still new, you might want to send it out for nitriding - I don't think its that expensive.

In my experience, the bigger concern here is avoiding tight spots where the stainless braid will abrade and destroy whatever it comes in contact with. I don't think I've ever seen it the other way around. FWIW, I've come to prefer the ProLite 350 (or similar) hoses. These typically have a nomex braid instead of stainless and are usually either black or blue in color. These hoses are WAY easier to work with than stainless (you can cut it to length with a razor blade - it won't puncture your fingers), use the exact same hose ends and have pressure capacities beyond anything you're likely to need, and they're lighter than stainless, too. If you do need higher pressure or temperature abilities, the standard stainless probably wouldn't have fit the bill either - for high temps you'll want the teflon lined stuff (which requires special hose ends) and maybe some FireBraid, and for things like power steering, there is specially made hose for that purpose.

That's great that you've found a solution you are happy with - I always prefer a simple, elegant solution too. One thing that you didn't mention was the system pressure that you are running. If you are using straight water, I think you'll really want to run a higher system pressure than stock to regain some of the headroom for nucleate boiling protection that you lost by not using anti-freeze. I found this graph of pressure vs. boiling point for water that might be helpful... A data table for the graph can be found here: http://www.engineeringtoolbox.com/boiling-point-water-d_926.html

Agreed. The extra capacity in my case comes simply from the LD pump, some mild porting in the water passages in the front cover (the stock casting is not very flow-friendly once you look at it) a single core Ron Davis Radiator, and a shrouded stock mechanical fan (much simpler and flows a lot more air than any electric I could fit in there). With standard coolant I had chronic problems on hot summer days in slow traffic, not so much under power or at speed. Since I've changed to NPG-R, this has stopped for the most part - I still see some temperature creep in slow traffic on the hottest days (survived the Woodward Dream Cruise this year), but you should also take into consideration that I have protection against boilover to over 300 degrees F! Running 210 for short periods in traffic seldom happens, but shouldn't hurt anything if I'm not getting uneven cooling across the head due to nucleate spot boiling. The other thing that I took into consideration was that the NPG-R has those temperature capabilities at stock or less system pressures. I still run a full interior and heater, and need it sometimes here in Michigan! I really didn't like the idea of running really high system pressures with the 30 year old stock heater core and 10 year old stock molded heater hoses in the cabin. If you modify the cooling system for a reservior tank and pressure cap on the low pressure side you can actually run with a zero psi pressure relief and still get boilover protection to over 300 degF. I didn't go this far - currently running a stock pressure cap for simplicity. In the overall scheme of things ~$70 for coolant is peanuts compared to the money and time I have wrapped up in this thing, and I've been really pleased with the performance so far.

Maybe Paul can confirm - I've always taken the "no-retorque" thing to mean that they've tried to design the gasket so that it doesn't have to be re-torqued, not so much that it can't be re-torqued.

I guess I'm having trouble imagining how the procedure I mentioned above could cause any damage to any head gasket. Maybe if you loosened all of the head bolts at once and then retorqued them it could be a problem, but if you do one at a time I can't see how this could possibly hurt anything. This isn't some sort of difficult invasive procedure - it takes maybe 10 minutes and most of that is R&R'ing the valve cover (I am assuming that you have proper tools and a decent torque wrench). This used to be an "every 10k mile" service item.

I have never had good luck with the sealant stuff - yes it stops the leak, but I've also clogged two heater cores. If you are going to use it, make sure that the water to the heater core is blocked off, and flush the system after the leak stops. Now on re-torqueing... Seriously guys? Just re-torque the damned thing. If its already leaking what's the worst that could happen? There - I said it out loud. Back each bolt off 1/4 turn and torque to spec (with the engine stone cold of course) and see what happens. Do each bolt one at a time and in the proper torquing sequence (i.e., loosen the first bolt, then re-torque it, then move on to the second. Don't loosen them all at once) FWIW, I always retorque a new head gasket at least twice with a few heat cycles between each retorque. Granted I am using a different gasket - it's the Nissan comp gasket that requires machined recess for the separate fire rings, so its easier to have small leaks like this. Retorqueing has solved this problem at least once for me.

You can also look here: http://e85vehicles.com/e85/index.php http://e85forum.com ...but to answer your question, the difference in AFRs for stoichometric mixtures for E10 vs E0 is ~14.1 vs 14.7 AFR, or about a 4% increase in fueling for E10. Not a huge difference, and if anybody is destroying their engine by using E10 instead of E0 they had a pretty p*ss poor tune to begin with. Timing requirements are a little different at higher ethanol percentages, but for the most part you can use the exact same timing as you use for E0, even with E85. The main thing that you might notice is that you may be able to run a bit more timing if you were artificially backing the timing off to avoid knock with E0, due to E10's higher octane.

I appreciate that you are being conscientious, but I hope you were going to move the conversation to a new thread, as I think several people seemed interested in ir - maybe just post a link to the new thread here...

Quick update - I checked with ATP turbo last week, and these are on sale now. However, here was their response when I asked what was needed to upgrade my GT4294R: ...so for now the only thing I'd get to keep would be the turbine housing, and it's not clear, but it sounds like in the future I might only have to change the compressor wheel and the compressor housing. Not sure how this classifies as "interchangeable"...

No, I meant rich - the ethanol/methanol curves exhibit a pronounced peak in flame speed, at 1.1 equivalence (.91 lambda), and then decrease noticeably as the mix gets richer. The gasoline curve is much flatter.

Interesting - I was going to go find and show that flame speed vs. mixture graph in my next post, then your link was using the same graphic. I'll show it again here just to keep things simple: I remembered that Ethanol slows down appreciably at higher mixes, but couldn't remember what gas did - thanks for the link!

Not absolutely sure, but I believe that it would read full rich wit zero oxygen - I am pretty sure that misfires will show a lean condition.

Yes, I am making some assumptions. However, remember that in the cases stated, the wideband was reading rich, which says that there shouldn't have been unburned oxygen in there - unburned fuel/air mix usually reads lean, due to its oxygen content. I'm trying to concentrate specifically on a situation where richening the mixture alone causes the EGTs to increase, and understanding why this happens. I'm thinking there may be a linkage between flame propagation speed and fuel mix - perhaps the burn rate slows down enough with a rich mix that the fuel is still burning after the exhaust valve opens. The root cause of this would be a combination of timing and fuel, though, and not the same as the fuel being ignited in the exhaust. I know that propagation speed changes at the extremes for E85 - anybody have data on C16? This is a different effect, caused by the throttle transition often leading to a lean mix from either a decel fuel cutoff, or just a lean condition in general on decel. This rich/lean transition introduces oxygen into the the exhaust, allowing the previously rich mix to burn.

This is a branch from another thread - I wanted to continue the discussion, but didn't want to hijack the thread. Here's what got me thinking... On my last set of dyno pulls, this wasn't exactly the behavior that I observed. As I've noted before my setup always seems to have some pretty high EGTs. Running E85 has helped considerably with its inherently lower combustion temps, but I when I tried leaning the mix out a bit, power went up, just as Tony and Jeff observed, but so did my EGTs. Still not as high as they were on gas, but higher none the less. I've also been speculating that the cause for my high EGTs was fuel burning in the exhaust, and this does seem to be corroborated by the fact that the pistons and chambers looked really good the last time I had the engine apart, when temperatures that I was observing on gas (~1850 degF ) should have left some observable evidence had they been occurring in the combustion chamber. (Full disclosure - I did drop a valve seat, but it was the intake valve, and once we got into it, it appears to have been improperly installed, so not due to a thermal meltdown). The thing I'm a bit hung up on is that if we are measuring a rich mixture (and even 13.8 is still quite a bit rich compared to stoich), then there should not be any oxygen in the exhaust to support the further burning of the excess fuel. So how's the rich mixture burning in the exhaust? I think that I have an answer to my setup at least. I'm using a pretty big turbine housing - it's a full T4 split housing with a 1.15 AR and a full 4" exhaust, plus a 60mm wastegate with essentially its own 2.25" exhaust. Here's a plot of my exhaust Backpressure on my best dyno pull: As you can see, the exhaust backpressure (measured at the turbine inlet) is the same as or a fair amount lower than the intake manifold pressure. To add to this I have a fairly aggressive cam - here's the profile as installed at the overlap period: So, it follows logically that I'm blowing some unburned mixture through during the overlap period, which is how the oxygen is getting in there. Now, if this is the case, then adding extra fuel should shouldn't result in higher temperature, since it will still be a rich mixture when it blows through to the exhaust, and the oxygen getting injected into the exhaust will only be able to burn so much fuel and the extra fuel will still be unburned. Further, this is only plausible if the exhaust backpressure is lower than the manifold pressure - otherwise you would get exhaust reversion rather than blowthrough. Now from what I remember, Jeff's turbine housing and AR is smaller than mine, so I'm having trouble imagining his exhaust manifold pressure being low enough to cause appreciable blowthough. So what do you guys think? What am I missing here - for some reason Jeff and Tony observed a markedly different result, and I believe that this is what they observed. Seems like something else is going on here - Gents?

This is an interesting topic that I'd like to expand on - Jeff, Tony, any objections if I take your posts and use them to start a new thread, so as not to hijack this one? I don't have time right now, but will try to get to it tonight... EDIT: Here the new thread: http://forums.hybridz.org/showthread.php?p=1111763#post1111763

Um... before you pull the head, you did notice that the dipstick is missing, right? edit: never mind - I now see it laying on the relay box in the first pic.

Careful with the octane numbers - other countries may not use the same system that we do in the States - I think their 98 is more like our 92 or 93