Pyro

Another thing to consider is the new cam grinds tend to wear out quicker. Yes, the 151 cam is/was a dog, but it was designed by gm to last a long time, so it got slow and low ramps. The xtreme series compcam have very fast ramps but I would not run one with just any motor oil, since the removable of anti-wear additives from most engine oils. So, I tend to stay with the older high energy or magnum series compcams.

I ran the 292H with a 350 (362 cid) 11:1 cr, rpm intake, holley 3310, full length 1-5/8 headers, dart 200cc iron eagle heads, 2-1/2 dual exhaust with areochambers, 3.90 r200, gm t5, 26x8 my drag tires on 15x 8 rims. ran 11.7's at 120 and 10.7 at 135 with 175 shot n20. 120 mph should be considered the safe limit for the stock rear end assembly. engine pulled hard to 7000 rpm but got my best et's with 6500 shift points.

maybe you are confusing advertised duration and at 0.050" duration. a 206 degrees at 0.050" is typically 252 degrees advertised (seat to seat).

a 9:1 cr engine with stock heads would do well with intake duration between 206 and 210 and 212 to 218 on the exhaust. a stock converter would be better than a 2300 stall but 2300 is still ok in a light car. if you plan on using a carb then use 108 to 110 lsa.

stock cr is more like 9.5:1. the head gasket, piston dishes, piston below deck, and cylinder head cc can all be considered the combustion chamber size. try using about 85cc (10+6+5+64). A 3.54 gear, 2300 stall, 9.5:1 cr would like a cam in the 218 to 224 degree range at 0.050".

"build the engine around the turbo" what does that mean?

81 to 83 280zx with 5 spds have the 3.90's. the 292H has a rough idle. makes great power after 3000 rpm. works great with a rpm intake and a 750 holley 3310.

wow! 12:1 cr! that is a lot. maybe that is why the hp is kind of high for a little cam and stock heads

if you put enough cam in it, it will not seem like it is over revving when going down the highway. a compcam 292H will pull to 7000 rpm with the right valve springs. That is about 140mph with a 3.90 gear, 26 inch tires, with a 1:1 top gear (3rd gear in a th350). that cam requires a 3000 stall and 10 to 10.5:1 cr and makes 400hp with almost stock heads

get a 3.90. use the proper stall for the cam used automatics are better suited for drag racing.

majestic turbo in dallas texas

Well then it must be set back. Got to have the shifter in the right spot. The T5 is a nice transmission. so, not a big fan of the ford 4 speed.

if it is in place and working then leave it alone. setting the engine back a few inches is not going to help much. The engine may even run cooler with the engine more forward because it gives much more room around the firewall for hot air to get out. if you want to lighten up the front end then install some aluminum parts (heads, intake, water pump, radiator) and add a mini-starter. moving the battery to the back will also help a lot. If you want even more power, then install a 350 crank.

sounds like a good plan. The better the head and cam flows, the less boost you will need to make your power goals.

hughdogz, don't worry. 400hp is a lot and will certainly entertain you. Should be able run a very low twelve or even a high eleven 1/4 mile if traction is good enough. I feel you can make your 375 rwhp goal (430 crank hp) with a msa stage 1 turbo cam and 22 psi of boost. Otherwise, the stock cam would need 24 psi to make 330 rwhp.

shift the t5 slow and it will live. no full power in 5th gear and avoid hard clutch dumps. I ran mid 11's at 120mph and mid 10's at 135mph (on n02) with my t5 using MT drag slicks. Just try not to shock it. stock wheels and tires will spin before the trans breaks.

nipponpower.com SPEC stage 2 (kelvar disk) is a nice clutch, takes a few hundred miles break in period to hold strong. SPEC stage 3 had too quick of engagement for a street car, so it chatters.

The NA is still a small cam, you shouldn't feel any difference. However, since boost will be delayed, your car will feel slower on the street. That hard kick at 2800 rpms will not happen until 3500, which makes the car feel like a dog. I went through the same process. Switched turbos without swapping the cam and the car lost all low speed torque due to turbo lag and ran out of cam earlier (short power band). sure it ran better on boost, but the loss of the low rpm boost was a big problem for me. So, I installed a MSA stage 1 turbo cam and increased the rpm range. Yes, it is faster now, but I miss the stock turbine. Next time, I'm leaving the turbine alone since I drive on the street most of the time (no more time to race it). Or maybe try a turbine a little closer to the stock setup. The nice thing about the stage 3 is while driving on the highway. It runs about 10 inhg of vacuum going down the road at 80 mph. The stock turbine was about to start boosting at 3000 rpms. I could hardly drive over 80 without the boost coming on. However, the stage 3 requires a down shift to pass where the stock turbine did not. I hope you have better results than I did. For the track the stage 3 is the way to go, for a pure street car, I'm not sure. I would have less lag with an aftermarket efi system with ignition timing control.

A stage 3 turbine will start boosting at 3000 and hit full boost by 3500. Not the best for a stock cam that quits pulling by 5000. An increase in cam duration should go along with that turbine upgrade. I would at least install a 75 to 80 NA cam for another 500 rpms of useable power.

Could easily be a mild street car. Just install high flow components on the exhaust side to lower the exhaust side pressure. As your article says, "if the exhaust pressure is lowered than the intake pressure there will be no reversion" or something to that effect. Install a setup like this on a stock engine and it could handle more overlap. (T3 stage 5 turbine, high flow down-pipe, external wastegate, and a ported exhaust manifold). However, high flow exhaust components tend to make turbo lag.

Yes, good point jeff. I should steer away from those "general rules". It seems the amount of overlap tolerated by a turbo engine depends on the pressure in the exhaust manifold. Therefore, high flow turbines and free flowing exhaust manifolds can handle more over lap. When using a stock turbine on a L28et, avoiding overlap would be a good thing, since the exhaust pressures can become much larger than the intake pressure.

nice link! Thanks, I'm always looking for cam tech papers. I agree with you 100%. overlap is not a good thing for a turbo engine (especially with a smallish turbo). However, the stock NA cam is so small that is doesn't have enough overlap to worry about. The link focuses on when the exhaust valve closes and when the intake valve opens (overlap). If you look at the spec specs there is hardly any difference when the Z turbo and NA cam There are 3 turbo cams and have exhaust closure at 14, 8, and 6 atc, the non turbo 75 to 80 cam exhaust valve closes at 14 The turbo cam intake valve opens at 12 or 16 btc and the na opens at 16 btc. so the turbo cam with the most overlap is 26 degrees, the 77 to 80 na cam has 30. hardly any difference. However 8 more degrees on the intake does make another 500+ rpms of useable power.

248 degrees of duration is still a tiny cam with hardly any overlap to speak of even with 109 or 110 lsa. I know my msa cam is using 114 lsa. So that makes the overlap about the same with the msa stage 1 turbo cam as the stock na cam. Yes, I did the math. Both cams (msa stage 1 and the na) do have more overlap than a stock turbo cam that is for sure. However, my msa cam sure makes more power than a stock turbo cam. Do you want to make 500 hp with 30 psi of boost or 25 psi of boost?

I don't think that is possible. Why do you say it jumped a few teeth? Fyi, when checking the location of the timing marks, it can take as many as 12 engine revolutions to get the timing marks and chain marked links in the right place. Just pulling off the valve cover and rotating the engine to tdc and looking at the timing marks (1,2, or 3) is not the way to check which timing mark the engine is on. do a compression check. if there is low or no compression then the timing could be off.

I think you answered your own question. Sounds like you are getting too much fuel. soaked plugs don't work very well. check the things that make it run rich. high fuel pressure, bad connection at the temp sensor (2 prong connector), stuck starter injector, ect.... change the plugs, shut off the fuel pump, try starting with starter fluid only, if it kicks over, then you are running to much fuel.