240Z Turbo Posted June 27, 2003 Share Posted June 27, 2003 Well, I machined a template for the C4 pump bolt pattern. I just lay it onto the 280zxt bellhousing and transfer over the holes. I drilled them out and then spot faced the holes on the inside in a mill. Anyway, I now have a nissan bell housing that bolts up to the C4 transmission. I am now working on getting a 9.5" converter made that uses the C4 top and the 280zxt front cover so it bolts to the stock 280zxt flexplate. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted June 30, 2003 Share Posted June 30, 2003 I thought you were going to do a GM turbo 400 conversion? What changed your mind? Are you going to have parts manufactured for sale? I'm not happy with how my trans is behaving. It revs up 2-400 rpm when shifting 2-3. It goes up even higher if I leave it drive and stomp on it. I didn't install the shim to bring everything up to full pressure. Perhaps I should do that before ripping it out and looking elsewhere. Bernard Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted June 30, 2003 Author Share Posted June 30, 2003 Well, my motor is back 1" from the stock location so it made the fit rather tight. I mocked the 200-4R I originally wanted to do, but it was very close to the tunnel. 99% sure it would have worked, but the C4 is so much smaller for packaging. Perhaps in the future I will do the adapter for the GM/Olds tranny. I am not going to make a kit for this, but I will provide drawings for everything required. Just too much of a hassle at this point. I will keep you updated on the progress for those interested. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted June 30, 2003 Author Share Posted June 30, 2003 I'm not happy with how my trans is behaving. It revs up 2-400 rpm when shifting 2-3. It goes up even higher if I leave it drive and stomp on it. I didn't install the shim to bring everything up to full pressure. Perhaps I should do that before ripping it out and looking elsewhere.Bernard That sounds like a timing problem. Have you done any mods to the tranny/valve body? I have the valve body mods online. http://www.eng.fsu.edu/~jthagard/4n71b/ Quote Link to comment Share on other sites More sharing options...
Bernardd Posted June 30, 2003 Share Posted June 30, 2003 I did the mods as per the info you had for your mods. I did not do the mod for max line pressure as the info suggested. Another tranny guy talked me out of it. Timing issue??! Please explain. I have no clue how an auto trans works. Bernard Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted June 30, 2003 Author Share Posted June 30, 2003 these were the mods as given to me by Level 10 performance. Timing issues deal with the release of the 2nd gear band and the engagement of the 3rd gear clutches. Remember, the tranny has to release the 2nd gear band and at the same time engage the 3rd gear clutches, hence the necessity to have these events timed. I think the condition you have is commonly referred to as flair. My tranny also did that for a while, cannot remember what I did to solve it. If you did not drill the holes as specified it can cause these problems. Have you tried playing around with the modulator adjustment? Also, you can try placing a restrictor on the vacuum source for the modulator. This may help. Full line pressure is not bad on these trannies. It may help your problem, but I do not know. I am also not a tranny expert. BTW, could you tell a big difference after making these VB modifications? Did it shift much harder? Quote Link to comment Share on other sites More sharing options...
Bernardd Posted July 1, 2003 Share Posted July 1, 2003 I drilled the holes as specified. I have not played with the modulator at all. Can you give me some direction as to which way to start? Would I be lengthening it? Is it adjustable or do I have to buy parts and install? If the instructions are in the FSM I'll be ok. I'm just not sure which way(in or out) does what. My trans was in rough shape when I had it rebuilt, so yes it does shift much better. But it's the second to third shift that's not what I want it to be. I'd like it to be as firm as the 1-2 which is quick and solid. I will set the line pressure to max shortly and then start with modulator. Bernardd Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted July 1, 2003 Author Share Posted July 1, 2003 If you remove the line on the modulator there should be an adjustment on it. Mine uses an allen wrench. Adjust it in to raise the shift point(CW) and screw it out to lower the shift point(CCW). The modulator is pretty cheap, about $25. You need to get one for a turbo application, it has a silver dot on it. You may try calling Level 10 to get their opinion...ask for Pat. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted July 1, 2003 Share Posted July 1, 2003 I picked up a modulator after the rebuild. I never looked at it closely but the part # was for a turbo tranny. Never made any difference. Thanks Jim Bernard Quote Link to comment Share on other sites More sharing options...
jeffp Posted July 16, 2003 Share Posted July 16, 2003 Hi James, I was looking at your post and the bellhousing looks good. I have a question tho, are you sure the C4 is going to hold up to the abuse you are going to put it through? I have a suggestion, Ford made a C6 that fit the SB application on some of their trucks and vans. The C6 is a much beefier tranny then the C4 is. I have a good friend in Carson City that ownes a Ford junk yard, and he builds trannies. His name is Richard Haas, his number is 775 246-3444, just a thought here, but you might want to give him a call about the C6 application, he can get you one if you would like to go with a stronger tranny that the C6 has to offer. Just something to think about before you get full force into the C4 tranny. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted July 16, 2003 Share Posted July 16, 2003 Are you still planning on driving your car on the highway? It's going to scream without an overdrive. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted July 16, 2003 Share Posted July 16, 2003 It's going to scream without an overdrive ...or a LU. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted July 17, 2003 Author Share Posted July 17, 2003 The C4 can be made to hold 900hp with no problems. However, the time between rebuilds is more frequent than a GM tranny. Another advantage is cost and the size of the tranny. It is cheap to build the c4 to hold for my application, especially when I don't make 900hp and my car weighs 2565lbs. Hell, I can get a Art Carr C4 race tranny for $1500. The tranny is also very small, much smaller than a GM tranny or the 200-4R. As far as OD, well.... Quote Link to comment Share on other sites More sharing options...
jgkurz Posted July 18, 2003 Share Posted July 18, 2003 My Dad runs a C4 with a trans-brake in his 427FE 69 Mach1 Mustang. It run's low 9's on 11.5 slicks and still has a full interior. So far it's held together. FWIW, the C4 is worth about .3 sec in the 1/4 mile over a C6. Quote Link to comment Share on other sites More sharing options...
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