Well, my TO bearing did not make it in this weekend, so in my spare time I decided I should check the piston to valve clearance. After all, that is what I started this thread for, to see if anyone had run various cams with the 4g63 head on the SOHC flat top pistons. I just don't like the idea of the clay method and not really knowing when the valve events occur so I grabbed the hack saw and made my own checking device.
Here is step #1, it took a while but seeing inside must be worth it
Here it is with the stock turbo cams installed and only 1 intake and 1 exhaust on number 4 where I will be looking
A view of the chamber show the 2 valves are fully in tact for measurements.
Here is the final result with already squished head gasket.
This is what happens when my parts run late. A little JB weld should put it back together.
The car is together and running. I let it warm up and then checked compression. 225psi at 6400 feet altitude. My 2.0 was 130psi at altitude. I believe I am 18% lower on the numbers being this high, so at sea level the 2.4 would show about 270psi cranking. My best guess would say it is right around 12:1 compression. I am going to drive it for a week or two with the wastegate loose to see how everything does.
Well I put about 200 miles on it over the weekend. The first 150 miles with the wastegate open so it built no boost. Everything seems good, I had to retune a bit for the extra displacement. I pulled timing across the table to be conservative. I also richened the fuel a bit to start with. Today I connected the wastegate and ran it with the factory 9psi boost. I gave it a good 5 second 4th gear pull, seems smooth. I don't notice any detonation, but I don't have a knock sensor so I am listening only. My exhaust is quite though. I have heard light detonation with pump gas. I think next weekend I will use a det can to listen better. It certainly has more torque off the turbo, but no way to know how much without a dyno. The high compression is a little weird to get use to, it kind of reminds me of a motorcycle engine now. It revs pretty fast and slows down quickly. It starts instantly and when you turn the key off it dies fast. Just different. Sometimes the starter will catch it on compression and it almost stalls the starter, but usually it cranks up fine. Pretty interesting experiment, we'll see how long it lasts before the HG or pistons go.
Well I put about 200 miles on it over the weekend. The first 150 miles with the wastegate open so it built no boost. Everything seems good, I had to retune a bit for the extra displacement. I pulled timing across the table to be conservative. I also richened the fuel a bit to start with. Today I connected the wastegate and ran it with the factory 9psi boost. I gave it a good 5 second 4th gear pull, seems smooth. I don't notice any detonation, but I don't have a knock sensor so I am listening only. My exhaust is quite though. I have heard light detonation with pump gas. I think next weekend I will use a det can to listen better. It certainly has more torque off the turbo, but no way to know how much without a dyno. The high compression is a little weird to get use to, it kind of reminds me of a motorcycle engine now. It revs pretty fast and slows down quickly. It starts instantly and when you turn the key off it dies fast. Just different. Sometimes the starter will catch it on compression and it almost stalls the starter, but usually it cranks up fine. Pretty interesting experiment, we'll see how long it lasts before the HG or pistons go.
What are you tuning with and why not use a knock sensor?
Megasquirt, so no knock sensor. Supposedly you can use a knock sensor with it but I never heard of anyone having success with that. Scary huh? It is almost unheard of for people with DSMs to not use a knock sensor to tune with, but it is what it is.
Megasquirt, so no knock sensor. Supposedly you can use a knock sensor with it but I never heard of anyone having success with that. Scary huh? It is almost unheard of for people with DSMs to not use a knock sensor to tune with, but it is what it is.
I tuned my car and many others for years with no knock sensor (hondas, scubyies, DSM's etc...) it's all about being thoughtfull adn paying close attention to the engine behaviour and sound. Then when you start to push the envelope you can read plugs on the street, or you can even see detonation as puffs of intermittant black smoke on the dyno. (looks different than running rich)
I drive it 60 miles a day to work. So far so good. I can get going from a dead stop so much quicker now without having to rev the engine. Just take off like a typical non turbo car and then boost hits quickly as well. As this point I am a little worried about how long it will last, but I am not going easy on it just because of that(got to have fun). I got on it several times yesterday and verified that the stock 2.0 turbo cams are too small for the larger displacement. I expected that, but didn't come across a set of cams yet. They flatten out pretty good above 4500rpm. Atleast I think it the cams causing that. I want to go with 272 cams to keep it nice for the daily commute. Otherwise I think 280's would be real nice for street/strip. I think its really going to open up with 272 cams so that is my next priority. As it sets right now, I bet I can surprise a few people at the stoplight. When they don't hear any rev, then instant rpm and gone across the intersection
There are some pretty long hills on my commute home and with the old 2.0 setup the car would pull between 3-5psi boost to maintain the speed limit of 65mph. Now I am a little less than zero on the boost gauge to maintain the speed limit on the same hills. So I am not even getting the engine to full throttle much less any boost. Like I said before, we knew the 2.4 was going to pick up torque and then add in the compression bump on top. I am happy with it.
I am at 500 miles on the setup now. The new CFDF clutch should be broken in well. When the car ran on pump gas with 2.0 I would get 27mpg. When I switched the 2.0 to e85 I had to increase fuel by 34% which put my mileage at 18mpg. With the 2.4 engine now I am getting 22mpg. I am only down 18% on mileage with e85 so that starts making the e85 actually cheaper than premium versus the old setup and being down 34% on mileage. The e85 around here right now is 25% cheaper than premium. So I'm finally saving a little bit by running it and getting the extra benefit
Get some logs up when/if you can. I'd like to see 70-90mph times and airflow numbers. Also after you get it tuned are you going to take it to the track?
____________________________
Matt
dd '90 GST, Holset H1C
This is a megasquirt car so no airflow numbers I'm afraid. I had no plan to take it to the track since overall it is a slow daily driver, but I would like to get it on the local dyno and compare to my friends talon who has the indentical setup to my old 2.0 setup. We should be able to compare the two and see what torque gains were made throughout the curve from the 2.4 and compression upgrade. Before changing my engine our setups matched in every respect, same exhaust sytems, mufflers, FMIC, turbo porting, cams etc. As close as two cars can be. We also both ran 18psi boost. His car is heading to paint jail this week, so we won't be able to hit a dyno until it is back. It will likely be a month before his car is back.
I talked to my friend about getting both cars on the dyno after his paint job, he also wants to do this. Hopefully in a month we will have results. I checked compression again at his house his and it showed 220psi on all four with his gauge at 6000 feet. Did not get any video, sorry, but I did make time to see Watchmen. I loved it, the smartest guy on earth, heh heh.
I set my dual boost switch for 14psi last night and tried it out. 14 pounds feels really good, pulls better than 18psi did with the old 2.0. That gives me 9psi on the low setting for typical driving and 14psi when the need arises.
I am way excited. This is the kind of stuff I like to see. I am glad it is working out for you. I hope she stays together. That is a HUGE jump in the compression numnbers. Far more than I thought it would be. Sick man.
Steven
____________________________
Mary Kay- Project 200mph
