millsn Posted October 23, 2011 Share Posted October 23, 2011 Anyone else following Dave Walkers variable length trumpets? Seems he's able to quickly discern the best length and optimise torque. I'm interested in this as my engine always feels a bit lacking there (ia m picky though). So what difference 10 lbft, is it worth investing? I don't think he maps mbe so I think I'd need to buy a set, can't imagine theyre cheap our permanent either Link to comment Share on other sites More sharing options...
Dignity Posted October 23, 2011 Share Posted October 23, 2011 "I don't think he maps mbe so I think I'd need to buy a set, can't imagine theyre cheap our permanent either" For me it was worth £135. To get the best from my set up I would have had to cut a hole in the bonnet which I did not want to do. Just by putting them on at the same length as my old trumpets I gained 4ft/lbs and 5bhp. This I believe is due to the different shape. More importantly it moved the torque curve into a more usable position. Not sure what you mean by being permanent?? If you send me a BM i can send you the RR graph to give you a better idea. Regards Colin Link to comment Share on other sites More sharing options...
millsn Posted October 23, 2011 Author Share Posted October 23, 2011 YHBM Link to comment Share on other sites More sharing options...
Dignity Posted October 23, 2011 Share Posted October 23, 2011 The Blatmail has come through without your email address. Can you resend and include your address in the content part of the message. Regards Colin Link to comment Share on other sites More sharing options...
Drumster Posted October 23, 2011 Share Posted October 23, 2011 Dignity, You should still just be able to reply to the 'private@blatmail' address anyway if that's what you're referring too. Works for me. Millsn, I might go the adjustable intake route as well. I'm starting from blank sheet and already have a bonnet cut-out so the cost of £135 against £100 for normal trumpets seems to be worthwhile. Link to comment Share on other sites More sharing options...
Dignity Posted October 23, 2011 Share Posted October 23, 2011 Quoting Aeroscreens: Dignity, You should still just be able to reply to the 'private@blatmail' address anyway if that's what you're referring too. Works for me Hi Chris, I didn't think that you could send attachments through that way? Colin Link to comment Share on other sites More sharing options...
Dignity Posted October 23, 2011 Share Posted October 23, 2011 Quoting millsn: YHBM Reply now sent Link to comment Share on other sites More sharing options...
Mr Locust Posted October 23, 2011 Share Posted October 23, 2011 Have had good experiences with tuned lengths of rampipes in the past when using DHLA carbs. Dave's article was quite interesting but I was hoping he would also look at the effect of mixing lengths on an engine ie whether it spreads the torque benefit usefully or compromises the whole thing. Link to comment Share on other sites More sharing options...
Drumster Posted October 23, 2011 Share Posted October 23, 2011 Dignity, Missed the point about sending attachments Link to comment Share on other sites More sharing options...
oilyhands Posted October 23, 2011 Share Posted October 23, 2011 The research on unequal length trumpets has already been done comprehensively by Steve Butts on his 250BHP K series, adding two long (200mm) trumpets brought the torque up cionsiderably (over 25lb/ft) below 4000RPM with very little affect on the top end. Autoteknix do an airbox with this combination off the shelf. Oily Link to comment Share on other sites More sharing options...
Dignity Posted October 23, 2011 Share Posted October 23, 2011 Link to Auto-Teknix. Airbox Link to comment Share on other sites More sharing options...
millsn Posted October 24, 2011 Author Share Posted October 24, 2011 Catch is I'm running a zetec which I imagine would behave differently. Looks like a big thing to have sticking out of your bonnet too. I think the zetec sits further forward than the K which limits the amount of room available. Personally I don't like the airboxes that stick out Formula style. I imagine on a K you would be Direct to head which must free up room. Link to comment Share on other sites More sharing options...
Jason Plato Posted October 24, 2011 Share Posted October 24, 2011 http://rides.webshots.com/photo/1165961920054871002UxAoxxsplit length trumpets from 2003 here In 2003 I was experimenting with trumpet lengths on my 210bhp 1600K , I ended up using 130mm trumpets which I had made up especially for me plus 19mm spacers . These changed the tuned pulse to the tune of +22bhp and +24lb torque in the mid range vs 90mm trumpets . It also meant that the trumpets now poke out of the bonnet , which is fine as I want a cold air feed anyway . Peter was also at emerald on the same day and tried my trumpets - with no gains on his 1800 . Peter will tell you that my timing was not optimised -but I have failed to find any more power by using the timing since that day . I believe that the 1600 needs a different length to the 1800 ,and the exhaust , cams and head being used also has different requirements . I dont know of anyone else who has done any practical tuned length work on the 1800 at the time Just be aware that the length of trumpet will need to clear the crossmember and you will have to make your own backplate and filter arrangement to fix onto the trumpets . Plus the long trumpets are bloody loud !!! thread here The split length trumpets worked but to use it properly you need to have individual cylinder ignition and fueling trim. and 4 lambdas ! Edited by - Dave Jackson on 24 Oct 2011 12:25:16 Link to comment Share on other sites More sharing options...
oilyhands Posted October 24, 2011 Share Posted October 24, 2011 Dave, Although it seems counter intuitive, Emerald added individual cylinder trims to cope, but in fact they were no needed.. Oily Link to comment Share on other sites More sharing options...
Jason Plato Posted October 24, 2011 Share Posted October 24, 2011 interesting . the problem for me was the bloody noise. it sounded great but was painful in the drivers seat, I do fancy doing some work on the duratec as everyone appears to be simply using the 90mm trumpet Link to comment Share on other sites More sharing options...
dannylt Posted November 21, 2011 Share Posted November 21, 2011 Ammo tried lots of combinations of spaced out trumpets on all my Duratecs... it was probably the pissing about of swapping them all that encouraged Dave to make these variable ones! They sound great - next time I go back I'm definitely having a set. Oh and yes, they did make a considerable difference, though all of them were loud. Link to comment Share on other sites More sharing options...
jackb_ms Posted November 23, 2011 Share Posted November 23, 2011 What would be the effect of longer trumpets on roller barrels? Would there be similar power and torque gain? There is quite a bit of room under the bonnet of a 21 Jack Link to comment Share on other sites More sharing options...
Jason Plato Posted November 24, 2011 Share Posted November 24, 2011 it's not so much how much are the gains from longer trumpets , it's more to do with what is the optimal induction length for an individual engine specification. finding the optimal length is made easier with adjustable trumpets but the actual length you end up at will be driven by cam, exhaust, timing , breathing and compression Link to comment Share on other sites More sharing options...
jackb_ms Posted November 24, 2011 Share Posted November 24, 2011 Dave Do you have the details of who made your trumpets and spacers? Cheers Jack Link to comment Share on other sites More sharing options...
Jason Plato Posted November 24, 2011 Share Posted November 24, 2011 the 130mm trumpets were specical order from Jenvey made to my spec to ensure they fitted the centers of the throttle bodies and didnt overlap at the tips. I think the actual drawing that Jenvey ended up using was the same as that on a circa 1997 Nissan BTTC car. the extension sections were made myself after I aquired some laser cut base plates from Bill Shirvington. the whole lot was several hunderd pounds. I still have the trumpets in the garage after all that you can appreciate why the variable length are a better option for testing. dj Link to comment Share on other sites More sharing options...
jackb_ms Posted November 24, 2011 Share Posted November 24, 2011 Well I've looked into cost as well and it seems that noone does a longer version for the RB at a reasonable cost ☹️ Jack Link to comment Share on other sites More sharing options...
Jason Plato Posted November 24, 2011 Share Posted November 24, 2011 reasonable cost for a 130mm ally trumpet I recall was about £100 each ? Link to comment Share on other sites More sharing options...
Jason Plato Posted November 24, 2011 Share Posted November 24, 2011 are your centers the same as Jenvey 42mm throttle bodies - like I said I still have the trumpets ... Link to comment Share on other sites More sharing options...
jackb_ms Posted November 24, 2011 Share Posted November 24, 2011 Dave I don't know ifthe the same as Jenvey 42mm throttle bodie. the Emerald adjustable one looked very tempting but would not fit which is a shame. Maybe you could lend them to me and I can check if they fit? 😬 Jack Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now