The V8 Owners Forum - Forum Index The V8 Owners Forum -
Welcome to the well-known V8 Owners Forum, no matter what you drive if its V8 Powered you'll be made very welcome.
 
 GarageGarage   1/4 Mile Table1/4 Mile Table 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

spider plate ??
Goto page Previous  1, 2, 3, 4, 5  Next
 
Post new topic   Reply to topic    The V8 Owners Forum - Forum Index -> Nitrous Oxide Area
View previous topic :: View next topic  
Author Message
kiwicar
Moderator Gold
Moderator Gold


Joined: 18 Nov 2006
Posts: 5461
Location: Milton Keynes


PostPosted: Sun Jul 04, 2010 10:19 am    Post subject: Reply with quote

Though I have neither a rover nor Nitrous oxide I would be very interested in what you have done, it is all tuning and keeps the old gray matter going.
Best regards
Mike
_________________
poppet valves rule!
Back to top
View user's profile Send private message
CastleMGBV8
Top Dog
Top Dog


Joined: 18 Aug 2007
Posts: 2334
Location: Sidcup, Kent, UK

1975 MG MGB GT V8

PostPosted: Sun Jul 04, 2010 10:28 am    Post subject: Reply with quote

Perry,

Pleased to here you have sorted out the problem and the performance is coming back.

Are you running the cam with any retard, now you have improved the breathing and fuelling potential it would seem logical to try and push the power band up the rev range a bit so that you can achieve more top end power and a higher terminal speed,

You would appear to have more than enough torque to get you off the line quickly, if your timing gear is not adjustable Real Steel do offset keys for the cam that would allow you to retard the cam by 4 deg. and i think this would cure the running out of puff over 4000 RPM you mentioned a while back.

You may off course already thought of this but if not, worth getting a key for a few quid and slotting it in next time you have the front cover off.

Top secret details? come on, send me a PM I won't tell anyone.

PS whats your MPH per 1000RPM in top gearand what RPM is currently peak BHP?

Regards,

Kevin.
Back to top
View user's profile Send private message
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Thu Jul 08, 2010 9:14 pm    Post subject: Reply with quote

Kev!
I cant remember mph per 1000rpm. If I get a mo over next weekend at the show I'll have a look. hp currently back up to 400 with 560 ft/lbs
I have got a 3 way cam sprocket, but its set to normal. Whats your thinking about setting it retarded??

Perry
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
CastleMGBV8
Top Dog
Top Dog


Joined: 18 Aug 2007
Posts: 2334
Location: Sidcup, Kent, UK

1975 MG MGB GT V8

PostPosted: Fri Jul 09, 2010 9:10 am    Post subject: Reply with quote

Perry,

Setting 4 deg. retarded will move the power band up the rev range and give you more top end power, as mentioned you seem to have more than enough torque to get you off the line but seem to remember you saying that the engine runs out of puff before you get to the line.

If you give me your tyre rolling radius I can work out the MPH/thousand RPM to see what the optimal power band would be for your terminal speed.

Diff is 3.07? and the TH400 is direct top gear I assume.

Another 500 RPM or so of additional power band may make all the difference.

Kevin.
Back to top
View user's profile Send private message
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Fri Jul 09, 2010 9:25 am    Post subject: Reply with quote

CastleMGBV8 wrote:
Perry,

Setting 4 deg. retarded will move the power band up the rev range and give you more top end power, as mentioned you seem to have more than enough torque to get you off the line but seem to remember you saying that the engine runs out of puff before you get to the line.

If you give me your tyre rolling radius I can work out the MPH/thousand RPM to see what the optimal power band would be for your terminal speed.

Diff is 3.07? and the TH400 is direct top gear I assume.

Another 500 RPM or so of additional power band may make all the difference.

Kevin.



Diff is 3.07:1
Th350 is 1:1 in top gear
Tyre diameter is 28" when not moving. I think its more like 29.5" at high speed

Pel
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
CastleMGBV8
Top Dog
Top Dog


Joined: 18 Aug 2007
Posts: 2334
Location: Sidcup, Kent, UK

1975 MG MGB GT V8

PostPosted: Fri Jul 09, 2010 10:48 am    Post subject: Reply with quote

Perry,

Ok lets assume the tyre is 29", that would be 4630 RPM at 130MPH ie 28MPH per 1000 RPM retarding the cam for more top end power should enable a higher terminal speed, 5000 RPM would be 140MPH.

If you still have sufficient torque to maintain yout 60ft times then your 1/4 times should be quicker

Also retarding the cam should help with your exhaust scavenging which with your restrictive heads is what is holding the engine back.

Check what the alternative slots will give in terms of advance/retard 4 deg.is what your looking for.

Kevin.
Back to top
View user's profile Send private message
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Fri Jul 09, 2010 10:01 pm    Post subject: Reply with quote

The slots in my cog will do +/- 4 degree's Kev!

I'll adjust the cam timing after the retro show to see how she runs at USC event Smile
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Mon Jul 12, 2010 4:58 pm    Post subject: Reply with quote

Sounds like this might help eh Kev??

It will be interesting to find out in a month or so Smile

Retarding by 4 degree's wont give me any valve fouling issues will it ?


Perry
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Mon Jul 12, 2010 5:06 pm    Post subject: Reply with quote

Youve got me at it now you Bugger Smile

I'm just running through the job in my head and I reckon I cxould have it all done and running in 4 hours??

Rad, alt, dissy and water pump out. Drop the front of the ARB (4 bolts), front cover off. Move the cogs and put it all back together !!

no!!
I'm not doing until after the Retro Show.. Too many alterations will get me confused again Smile
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
gelmonkey
Sergeant Monkey Face


Joined: 27 Jun 2009
Posts: 1304
Location: plymouth


PostPosted: Mon Jul 12, 2010 5:59 pm    Post subject: Reply with quote

Perry
I have done this to my engine.
You have the time to do this before the show you know Laughing
You know you want too.
Paul
Back to top
View user's profile Send private message
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Mon Jul 12, 2010 6:58 pm    Post subject: Reply with quote

gelmonkey wrote:
Perry
I have done this to my engine.
You have the time to do this before the show you know Laughing
You know you want too.
Paul


What was the net result Paul??
The engine certainly does run out of puff. 0-100 in 7 seconds and then another 3.6 seconds to gain 27mph when it was on song last year??

I would love to do this before the show, but I've had so much down time with engine breakage due to nitrous rtelated issues that I dont want to bog myself down again. I always moan at folk for doing more than one change to an engine and then not knowing why its not working. But I went and did it myself at the start of this year due to crap advice from an "expert"!! And most of my season has gone now. I've got Retro + USC and 1 RWYB in Sept.

At this moment I have just one thing to re tune, and thats the carb fuelling. Then I can adjust the nitrous fuelling back down to 250hp and see if I get a good pass. I also only have 3 bottles of nitrous for this weekend so its gonna be tight. If I can use 2 bottles for dialing in on Saturday I'll only have 3 passes in an 11lb bottle unless I start winding the pressure up to the 950-1000psi mark when its half empty. If I use about 2lbs per run the bottle is half empty after run 3. This is when the bottle pressure drops off hard during a run so it goes rich halfway down the track Sad
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
gelmonkey
Sergeant Monkey Face


Joined: 27 Jun 2009
Posts: 1304
Location: plymouth


PostPosted: Mon Jul 12, 2010 8:21 pm    Post subject: Reply with quote

Hi Perry
Im afraid I cant give you any results with this from my point of veiw as the car has not been run in anger.
I did it purely for extra top end grunt as the V8 has so much down the bottom end.
Having more top end should help me to blast past my buddy Malc and the chap that I look after in Thatcham.
Sorry I can't be of more help with this ,just thought I'd give Kevin's little thought flames a bit of a fan Very Happy
Cheers
P
Back to top
View user's profile Send private message
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Tue Jul 13, 2010 6:29 pm    Post subject: Reply with quote

Sounds like a plan dude!!
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
mgbv8
Gold Member
Gold Member


Joined: 18 Nov 2006
Posts: 5326


1975 MG MGB GT V8

PostPosted: Wed Jul 14, 2010 8:35 pm    Post subject: Reply with quote

I just thought up a new idea to make my own nitrous injection system that will be safe and easy to use on any V8 that has a single plane manifold. Easily tuneable without the need to strip the top off to change jets. The system consists of parts that are available to anyone off the shelf in the UK as long as you can use a drill and tap. I have the backing of a pro racer (this guy runs 6 seconds) in the USA who has offered to take my idea and make it all work including flow testing for just the cost of the postage to ship my manifold to and fro. But I think I can do it here over the winter to make a simple system that can flow from 50hp to 700hp. Once the parts are fitted to the manifold you will be able to fit all the pipework to 2 pairs of solenoids and that is it??
You can then run a 50 shot upwards depending on how much petrol you can deliver to go with the nitrous. And you will get even distributiuon to all 8 cylinders.

I'll keep this under wraps until I have a final design. But the final design will be FOC to anyone on here who can use a drill and tap Smile
_________________
Perry Stephenson
MGB GT + Rover V8
9.62 @ 137.37mph
Now looking for 8 seconds with a SBC engine
http://www.youtube.com/watch?v=nVscbPHgue0&list=UUqIlXfSAoiZ--GyG4tfRrjw

https://www.youtube.com/watch?v=eg3avnsNKrc&index=2&list=FLqIlXfSAoiZ--GyG4tfRrjw
Back to top
View user's profile Send private message Send e-mail
kiwicar
Moderator Gold
Moderator Gold


Joined: 18 Nov 2006
Posts: 5461
Location: Milton Keynes


PostPosted: Thu Jul 15, 2010 5:38 am    Post subject: Reply with quote

Hi Perry
good idea, can I suggest, when you have the design sorted, you draw it out and write up a description of the design and the principles that are key to it's function with the detail in where your design differs from others, stick it in an envelope and post it to yourself. Doing so saves allot of problems that can ocour if your design is successful.
Best regards
Mike
_________________
poppet valves rule!
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    The V8 Owners Forum - Forum Index -> Nitrous Oxide Area All times are GMT
Goto page Previous  1, 2, 3, 4, 5  Next
Page 3 of 5

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
Make payments with PayPal - it's fast, free and secure!


Copyright www.v8forum.co.uk 2006. All Rights Reserved,
Forum Disclaimer: Any posts in the V8 Forum are posted by individuals acting in their own right and do not necessarily reflect the views of the owner, administrators or moderators.