New remote turbo thread
#196
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Considering it was Porsches first computer and analog to boot, it obviously doesn't compare to the LH/EZK but it is programmed for a boosted engine and was used in the 300+ HP 924GT that won its class at LeMans.
Concerning the dieseling, I was referring to a diesel engine that ignites fuel with high compression and no ignition spark not the runon called dieseling that results from hot carbon in the combustion chamber.
Dennis
#197
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We are talking about the same thing. When something other than the spark plug sets off the air / fuel mixture it's pre-ignition. Reason why boosted cars should be running a colder spark plugs since this reduces the chance of the spark plug turning into a glow plug causing pre-ignition.
#198
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We are talking about the same thing. When something other than the spark plug sets off the air / fuel mixture it's pre-ignition. Reason why boosted cars should be running a colder spark plugs since this reduces the chance of the spark plug turning into a glow plug causing pre-ignition.
Dennis
#199
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Very good discussion.!!!....and generally spot on. It is a balance of boost, CR, intake temps, colder plugs, managing the knocks, measuring everything....it ultimately goes to reliable forced induction (SC or Turbo) over time (or mileage if you choose).
We haven't seen any real issues under 7-8 pounds and the engine (in reasonable shape) can cope. 5#'s boost and is easy and doesn't seem to really stretch any of the stock engine setups. But we know that.... In original setup/testing, we failed a head gasket, upon removal the engine (109,000miles) and subsequent inspection of it, the gasket was cleary already in very poor condition. I think I 've seen some other discussion threads regarding HG's and condition.
I'd be careful consistently running 15lbs of boost and anticipate that the ongoing maintenance cost is going to be incrementally high
unless the engine has really been gone through or an engine history with detailed files is available. Ultimately, I would build some safety into an engine to cope....mostly an upper end review and head studs. I like my cometics.....no problems running this car hard in 12,000 miles....touch wood.
Methanol at these levels of boost help a lot from what we can see so far and the install is pretty easy. We have it set up so that it doesn't even engage until 5lbs and a much larger reservoir (1.5gal) mounted in the boot. It adds to the fuel mixture a bit,but if the injectors need upsizing, they need upsizing...the ST lines this out clearly in the data logging and when it starts going south.
Shark tuning is critical to get your best shot at surviveability and tying all of the other elements (good gas/bad gas, colder plugs, etc), and its best to do it on a car by car basis.
......but there are a bunch of SC cars running around with good records.....and (I think) bolt on's and not much tuning.....please correct me if this perception is incorrect.
JT
We haven't seen any real issues under 7-8 pounds and the engine (in reasonable shape) can cope. 5#'s boost and is easy and doesn't seem to really stretch any of the stock engine setups. But we know that.... In original setup/testing, we failed a head gasket, upon removal the engine (109,000miles) and subsequent inspection of it, the gasket was cleary already in very poor condition. I think I 've seen some other discussion threads regarding HG's and condition.
I'd be careful consistently running 15lbs of boost and anticipate that the ongoing maintenance cost is going to be incrementally high
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Methanol at these levels of boost help a lot from what we can see so far and the install is pretty easy. We have it set up so that it doesn't even engage until 5lbs and a much larger reservoir (1.5gal) mounted in the boot. It adds to the fuel mixture a bit,but if the injectors need upsizing, they need upsizing...the ST lines this out clearly in the data logging and when it starts going south.
Shark tuning is critical to get your best shot at surviveability and tying all of the other elements (good gas/bad gas, colder plugs, etc), and its best to do it on a car by car basis.
......but there are a bunch of SC cars running around with good records.....and (I think) bolt on's and not much tuning.....please correct me if this perception is incorrect.
JT
Last edited by 89 928 turbo; 04-24-2008 at 11:00 AM.
#200
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So 5 psi would be a safe bet JT on a stock motor just looking for a minor gain?
I would like to do a setup like this not to break 400 HP, but to get more of a kick in the seat. The fact the car would sound like an F-14 at Zone-5 is just a fun accessory and benefit to it!
I would like to do a setup like this not to break 400 HP, but to get more of a kick in the seat. The fact the car would sound like an F-14 at Zone-5 is just a fun accessory and benefit to it!
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Last edited by Mongo; 04-23-2008 at 08:25 PM.
#201
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Actually, 7 lbs is very safe for a converted NA engine. General motors proved this in 79 when they took the 3.8 V-6 and bolted on a turbo mated with a 4 barrel quadrajet. This was a very hardy engine. The weakest point was the turbo bearings due to the lower quality oils they had at that time. No IC or water/methanol injection was required until the ante was raised with the Grand National engines. BTW If anyone is interested, I have a complete set up for the early version, less the quadrajet.
Dennis
Dennis
#202
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So 5 psi would be a safe bet JT on a stock motor just looking for a minor gain?
I would like to do a setup like this not to break 400 HP, but to get more of a kick in the seat. The fact the car would sound like an F-14 at Zone-5 is just a fun accessory and benefit to it!
I would like to do a setup like this not to break 400 HP, but to get more of a kick in the seat. The fact the car would sound like an F-14 at Zone-5 is just a fun accessory and benefit to it!
#204
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The easiest way to gain boost is by fooling the wastegate. This is done by putting a variable restricting valve on the boost line feeding the wastegate. I've seen these setups with $10 valves bought at the local hardware or more expensive valves that are electrically controlled by a dial in the instrument panel. I wouldn't use either of them without a good boost gauge to prevent overboost.
Dennis
Dennis
#205
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Some of the guys with 930s I knew a while back did the same thing and had a dial in the cockpit to turn the boost. It's as tempting as it is catastrophic if you're careless.
#206
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Yep, it is scary. I have the 930 1 bar wastegate in my 931 and even that is not safe if any connections are loose or blow off. It's happened once to me. The rush is great until it hits the rev limiter. From there it's all downhill.
BTW I have a boost gauge but it happened too quick to catch.
Dennis
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Dennis
#207
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Yes, you have to pay attention, low end plastic boost dialers and low end gauges are not the best cost savings now that you have invested all this and are putting an $5-8,000 (or more?) potential engine rebuild on the table.
We tried the little dial up plastic deal, but moved quickly away from it....its important to have a boost gauge with good range to see what's going on, but things do happen quickly.
We have never had an issue with tubing blowing/knocking off the various pieces parts, but we single and double zip tie everything.....you still have to check them out once in a while.
We tried the little dial up plastic deal, but moved quickly away from it....its important to have a boost gauge with good range to see what's going on, but things do happen quickly.
We have never had an issue with tubing blowing/knocking off the various pieces parts, but we single and double zip tie everything.....you still have to check them out once in a while.
#208
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Ehh, I don't think I'd ever turn the boost up if I went turbo on this car. Even at 10:1, sometimes I feel that compression is too high to turbocharge or supercharge, regardless of how durable the engine is.
#209
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We just go off a day tuning at the dyno with Chuck's car with good results.
Boost: 5.5lbs
Dyno was a DynoDynamics:
380.1 RWHP/406 Ft/lb
AFR's mostly in the mid to high 11's, timing next.....
30# injectors, RR-FPR @ 58psi, 96,000 miles all else Stock.
We will post the dyno sheets and AFR's as soon as we can figure out how to make them small enough to upload off the scanner.....I'd take some advise on this...
jt
Boost: 5.5lbs
Dyno was a DynoDynamics:
380.1 RWHP/406 Ft/lb
AFR's mostly in the mid to high 11's, timing next.....
30# injectors, RR-FPR @ 58psi, 96,000 miles all else Stock.
We will post the dyno sheets and AFR's as soon as we can figure out how to make them small enough to upload off the scanner.....I'd take some advise on this...
jt