360 HP estimate???

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Hot Metal said:
and we ran a lot of timing (36 total), with the 98oct leaded pump fuel we had.
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Does the UK use the European octane rating system? 98 in Europe is like 93 here in the US. Though you did have lead in it, so it is not really our 93 octane no-lead.

Just trying to help the OP get calibrated on the octane requirements he is going to need with N20.

OP, note that Hot metal is running lower DCR than you with that .590" lift solid flat tappet cam. So you will start out a closer to detonation issues than he did.
 
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Not sure on the ratings tbh, our worst stuff is normal unleaded 95ron. I have no experience of running N20 with todays fuel, N20 doesn't care how good a fuel you use but timing will be the key to stop a disaster happening especially with "clean" jetting tunes. Very hard to say what fuel he should use as it depends on the motor combination which is really what makes the power as to what fuel to use with how much timing and N20, generally premium with perhaps some additive would help of course. For a small 125 hit you could use just 2 or 4 smaller fuel jet with only a few deg. retard depending on fuel rating and still gain 6>7ths or more today. Wouldn't think you need anything like 100oct for a 125/150 hit.
 
OK, thanks, you answered the question actually. 95 RON (Research Octane Number) is like 87 over here. We use the average of RON and MON (Motor Octane Number).

And you also answered the question: combine timing and octane....as one would expect. Realize that he has notably higher DCR to start with than your motor, so it starts closer to detonation-land.

My favorite expression about N20: "Most of the problems are user error."
 
Yes most catastrophes are self inflicted, the most important thing with N20 is Timing, Timing and Timing again, but thats rich coming from me who only came back 1 deg on a 250 shot:rolleyes:
 
no nitrous without checking ring gap
and IDK about NO2 with hyper pistons in the first place
you would have to sneak up on the tune for sure
not that you should not for every build
 
If you don't have collecter extensions, you need them. 15 inch or longer.
 
Extensions usually help low end TQ numbers and can help throughout the range when correct in length. Open right out of the collector on most every naturally aspirated car is never the right approach.
 
crackedback said:
Extensions usually help low end TQ numbers and can help throughout the range when correct in length. Open right out of the collector on most every naturally aspirated car is never the right approach.
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Yep. Lot of people just cut them back to the heat after running them
 
Yes, I understand, and tnx... I 1st welded some on 43 years ago and found out that the low RPM torque improvement that was supposed to happen was real LOL.. a nice and easy improvement. The initial mention just seemed to relate to N2O, not in general, so I was wondering about the context.
 
nm9stheham said:
Is this in particular for N2O? Not following....
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Most situations call for some extension, and the bigger the need for more torque low and midrange (low stall), the longer they should be. Has nothing to do with nitrous.
 
Hot Metal said:
No, we built it as an NA motor with replacement TRW pistons/ring gaps. Then we discovered N20, we made several passes with a cheater system@125/150 hp jets and just that 1 pass with 250 jets (11.01), but we ran it on motor 90% of the time. Cheater solenoids only have a .093 orifice, so the 110n/110f jet 250 tune wasn't 250hp and the jetting on the kits was very rich back then. We encountered no problems at all with plugs (NGK7's) and we ran a lot of timing (36 total), with the 98oct leaded pump fuel we had.
If your gonna get a bit serious with it and run 200hp+tunes frequently with todays clean 5>10 smaller size fuel jet tunes, watch your timing and run 100oct fuel as its timing that kills motors with a lot of N20, then I would open your ring gaps some, otherwise I wouldn't bother if your only gonna run it every now and again with max 150hp tunes.
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I'm considering whether or not to spring for a trans brake valve body or not. My 2600 stall would start to push through the brakes at just over 2k I know if i get a transbrake it "should" stall to it's TRUE flash. Would the trans brake be worth the extra $500 over a regular full manual or should I just do a higher stall with with a regular full manual?
 
gregsdart said:
Most situations call for some extension, and the bigger the need for more torque low and midrange (low stall), the longer they should be. Has nothing to do with nitrous.
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This is great info. I'll get some welded up asap!
 
You can do some 12"+ extensions if you want, they will help the bottom end some NA and the cost is minimal, as are the gains. However, if you are going to use N20 say a 150 hit frequently and hit it off the line as I did (only way to do it in my book) the torque increase on the hit will be huge negating the use of a T-brake as well somewhat, but for an extra $500 you may as well get it, I would change the converter as well to something in the 3500 range, and up the cam to something like this if you wanna stay hyd.
20-229-4 - Xtreme Hi-lift Hydraulic Flat Tappet Camshafts...or
20-228-4 - Xtreme Hi-lift Hydraulic Flat Tappet Camshafts
but these comp fast rate cams don't help much with top end rpm as the lifters don't cope too well with them....Hughes hyd. cams are easier.
After running that old .590 solid DC cam I would never go hyd. in any performance type application where rpms are going to exceed 6000.

Or you could change the gears to something like 4.10>30's which should get you to the stripe ok and keep it pulling@5500rpm with the NA power you have with that mild 274H cam but that may slow you a touch in the 60's...the problem is with a 125/150 shot you'll be turning just over 6000 (4.30's) and with a hyd. it may give issues in the valvetrain......never easy is it. Personally I would go to a solid ft cam, of course all dependent on funds etc....how far do you want to take things as to how fast do you want to go is always the question....you could go 10's NA with a pair of those new TF190 heads, or anything with at least 280cfm flow+ a cam/inlet/carb/hdrs/converter to match if you have the $$$$$.
 
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Hot Metal said:
You can do some 12"+ extensions if you want, they will help the bottom end some NA and the cost is minimal, as are the gains. However, if you are going to use N20 say a 150 hit frequently and hit it off the line as I did (only way to do it in my book) the torque increase on the hit will be huge negating the use of a T-brake as well somewhat, but for an extra $500 you may as well get it, I would change the converter as well to something in the 3500 range, and up the cam to something like this if you wanna stay hyd.
20-229-4 - Xtreme Hi-lift Hydraulic Flat Tappet Camshafts...or
20-228-4 - Xtreme Hi-lift Hydraulic Flat Tappet Camshafts
but these comp fast rate cams don't help much with top end rpm as the lifters don't cope too well with them....Hughes hyd. cams are easier.
After running that old .590 solid DC cam I would never go hyd. in any performance type application where rpms are going to exceed 6000.

Or you could change the gears to something like 4.10>30's which should get you to the stripe ok and keep it pulling@5500rpm with the NA power you have with that mild 274H cam but that may slow you a touch in the 60's...the problem is with a 125/150 shot you'll be turning just over 6000 (4.30's) and with a hyd. it may give issues in the valvetrain......never easy is it. Personally I would go to a solid ft cam, of course all dependent on funds etc....how far do you want to take things as to how fast do you want to go is always the question....you could go 10's NA with a pair of those new TF190 heads, or anything with at least 280cfm flow+ a cam/inlet/carb/hdrs/converter to match if you have the $$$$$.
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would the intake, carb, and headers I am already running not work? ALso I may go solid lift cam for now since this is a mostly track car.
 
Airgap, 750DP is a good set up, if you went for the 10's they would still work ok but be somewhat inadequate in my opinion...then I would go for a Victor intake, a 5000 min stall and at least a proper 950>1050 4150 with 1.3/4">1.7/8" headers.
 
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