Honda Prelude Type 'S' Supercharged K20
Discussion
Ooo, always fancied a white one!
So lets talk figures
Ok so a few things to know first, the engine was dynoed at 305bhp and bang on 200lb/ft of torque, the torque curve pretty much mirrors the N/A curve but plus 40%. This engine was dynoed with a full 3" exhaust that was stupidly loud and not my hot chocolate. I am running the car with a 2.5" header collector, a high flow CAT & the cars original 2.25" exhaust system, its beautifully quiet and does not impeed on the supercharger noise at all, however I reckon its down a few ponies at high rpm's..
305bhp but probably less now!
200lb/ft.
Kurb weight originally 1310-1330kg, now weighs 1250kg with a full tank of fuel etc. Plan is to get it below 1200kg.
244bhp/ton (the e92 M3 is 262)
Now uses a glorious 6 speed gbox that is almost on par with the S2000 - I think this swap is worth it just for the gearbox!!
205/45/16 tyres.
Honda Accord TSX 0.659 6th gear.
Gearbox info:
Assuming an 8500rpm shift point.
FD 4.764
1st 3.266 37.8mph
2nd 2.13 57.9mph
3rd 1.517 81.3mph
4th 1.147 107.5mph
5th 0.921 133.9mph
6th 0.659 187.1mph
With the smaller 16" wheels I am running the max speed per gear is lower than the CTR with 17's. The ratios feel quite close together but its great fun banging up through the gears!
By fitting the accord 6th gear my motorway rpm's have dropped from a calculated 3760rpm down to 3180rpm. The car still pulls well up over hills and with my Ultragauge I have seen motorway economy as high as 44mpg (60mph lol).
So lets talk figures
Ok so a few things to know first, the engine was dynoed at 305bhp and bang on 200lb/ft of torque, the torque curve pretty much mirrors the N/A curve but plus 40%. This engine was dynoed with a full 3" exhaust that was stupidly loud and not my hot chocolate. I am running the car with a 2.5" header collector, a high flow CAT & the cars original 2.25" exhaust system, its beautifully quiet and does not impeed on the supercharger noise at all, however I reckon its down a few ponies at high rpm's..
305bhp but probably less now!
200lb/ft.
Kurb weight originally 1310-1330kg, now weighs 1250kg with a full tank of fuel etc. Plan is to get it below 1200kg.
244bhp/ton (the e92 M3 is 262)
Now uses a glorious 6 speed gbox that is almost on par with the S2000 - I think this swap is worth it just for the gearbox!!
205/45/16 tyres.
Honda Accord TSX 0.659 6th gear.
Gearbox info:
Assuming an 8500rpm shift point.
FD 4.764
1st 3.266 37.8mph
2nd 2.13 57.9mph
3rd 1.517 81.3mph
4th 1.147 107.5mph
5th 0.921 133.9mph
6th 0.659 187.1mph
With the smaller 16" wheels I am running the max speed per gear is lower than the CTR with 17's. The ratios feel quite close together but its great fun banging up through the gears!
By fitting the accord 6th gear my motorway rpm's have dropped from a calculated 3760rpm down to 3180rpm. The car still pulls well up over hills and with my Ultragauge I have seen motorway economy as high as 44mpg (60mph lol).
Here is a shot of the ultra gauge:
This clever little device plugs into the OBDII port and allows me to view all sensors, read and clear fault codes and most importantly gives me all sorts of fuel economy figures. I know lots of people don't give a crap about fuel efficiency but I enjoy chasing these numbers as much as bhp! I fitted the lowest front splitter I can find not only cos it looks drokking cool but it should also give me some aero aids
Future plans for fuel economy:
Upper grill block.
Manual supercharger bypass for a few percent increase at motorway speeds - the bypass can close at partial vacuum.
Tidy up underside aero, things such as partial engine floor & splitter.
Install EGT sensor.
Install a water hydrolysss unit, lean out the mixture and advance the timing to experiment with fuel economy.
Switcheable warm air intake.
Future plans for bhp:
Custom inlet manifold with charge cooler.
Either M90 or M112 latest gen supercharger - Gotta love the instant power
Perhaps a dual 2" high flow but quiet exhaust.
This clever little device plugs into the OBDII port and allows me to view all sensors, read and clear fault codes and most importantly gives me all sorts of fuel economy figures. I know lots of people don't give a crap about fuel efficiency but I enjoy chasing these numbers as much as bhp! I fitted the lowest front splitter I can find not only cos it looks drokking cool but it should also give me some aero aids
Future plans for fuel economy:
Upper grill block.
Manual supercharger bypass for a few percent increase at motorway speeds - the bypass can close at partial vacuum.
Tidy up underside aero, things such as partial engine floor & splitter.
Install EGT sensor.
Install a water hydrolysss unit, lean out the mixture and advance the timing to experiment with fuel economy.
Switcheable warm air intake.
Future plans for bhp:
Custom inlet manifold with charge cooler.
Either M90 or M112 latest gen supercharger - Gotta love the instant power
Perhaps a dual 2" high flow but quiet exhaust.
Thanks for the comments! I really intend to enjoy it this summer, car shows, trip to Europe and just general fun 'cruising' around are definiately on the cards!
This summer was spent driving around working out any problems, luckily it never broke down but there is a list of things I am working through to get it driving 100% like an OEM installation. Vibrations & reliability are my main concerns and it needs to be smooth as silk hence the redesign of the engine mounts to incorporate all 4 original H22 prelude mounts. If I went down this route to begin with the conversion would have been a little cheaper! Purchasing a whole car to begin with was expensive up front but the benefits were not having to piece everything together, I could try out the engine first hand & be confident it all works, no extra expense in mapping and the best bit is that with most bits sold to this date the whole engine, box, supercharger, ECU, wiring, etc cost me just a shade under 2k. I think I still have about £500 worth of stuff left to sell but these are the bits that will take a while to shift on!
I forgot to mention 1/4" times. Ok so I have never ever done a run what you brung drag event and the first 3 runs out of 12 were dry, my 3rd run was the best and I managed the following:
13.9 1/4
2.45s 60ft
100mph trap speed.
My fastest trap speed was 101mph.
The car was spinning 1st and 2nd in the dry and this was without a LSD, hopefully with my helical LSD thats now installed and hopefully running boost by gear I should be able to get my 60ft times down a bit.
This summer was spent driving around working out any problems, luckily it never broke down but there is a list of things I am working through to get it driving 100% like an OEM installation. Vibrations & reliability are my main concerns and it needs to be smooth as silk hence the redesign of the engine mounts to incorporate all 4 original H22 prelude mounts. If I went down this route to begin with the conversion would have been a little cheaper! Purchasing a whole car to begin with was expensive up front but the benefits were not having to piece everything together, I could try out the engine first hand & be confident it all works, no extra expense in mapping and the best bit is that with most bits sold to this date the whole engine, box, supercharger, ECU, wiring, etc cost me just a shade under 2k. I think I still have about £500 worth of stuff left to sell but these are the bits that will take a while to shift on!
I forgot to mention 1/4" times. Ok so I have never ever done a run what you brung drag event and the first 3 runs out of 12 were dry, my 3rd run was the best and I managed the following:
13.9 1/4
2.45s 60ft
100mph trap speed.
My fastest trap speed was 101mph.
The car was spinning 1st and 2nd in the dry and this was without a LSD, hopefully with my helical LSD thats now installed and hopefully running boost by gear I should be able to get my 60ft times down a bit.
Daugaard said:
How much higher is the k20 in comparison to the h22?
Edit: The overall size of it.
The k20 engine is pretty much the same size, the rocker cover is narrower which gives the illusion its a smaller engine. It is certainly lighter, it doesnt have balance shafts for a start and as its a gen newer than the H22 & it uses less materials in its construction. I am sure I read somewhere the engine + gearbox was in the region of 20+kg lighter which is a good difference!Edit: The overall size of it.
Edited by Daugaard on Friday 31st January 09:20
My car has ended up 70kg lighter, measured using a weigh bridge. Its kurb weight was within 10kg of the published figures from Honda so I would say their scales were calibrated pretty good that week!
The only other weight saving I have done is a 10kg lighter battery and removed the A/C. The engine did have a the ATTS attached which must have weighed a good 20kg!
The engine is infact taller, the head is sat roughly at the same height but the sump now sits level with the sump guard, whereas the H22 sat a good inch higher. What also doesn't help is that the inlet manifold is very close to the underside of the bonnet. In the EP3 & CTR this isn't an issue due to the high bonnet line but mine is so low and it rakes down at the front which doesn't help! I have ended up having to cut a tiny bit of the underbonnet support structure away.
Mudgey said:
Here is a shot of the ultra gauge:
This clever little device plugs into the OBDII port and allows me to view all sensors, read and clear fault codes and most importantly gives me all sorts of fuel economy figures. I know lots of people don't give a crap about fuel efficiency but I enjoy chasing these numbers as much as bhp! I fitted the lowest front splitter I can find not only cos it looks drokking cool but it should also give me some aero aids
Future plans for fuel economy:
Upper grill block.
Manual supercharger bypass for a few percent increase at motorway speeds - the bypass can close at partial vacuum.
Tidy up underside aero, things such as partial engine floor & splitter.
Install EGT sensor.
Install a water hydrolysss unit, lean out the mixture and advance the timing to experiment with fuel economy.
Switcheable warm air intake.
Future plans for bhp:
Custom inlet manifold with charge cooler.
Either M90 or M112 latest gen supercharger - Gotta love the instant power
Perhaps a dual 2" high flow but quiet exhaust.
that gauge is very cool!!This clever little device plugs into the OBDII port and allows me to view all sensors, read and clear fault codes and most importantly gives me all sorts of fuel economy figures. I know lots of people don't give a crap about fuel efficiency but I enjoy chasing these numbers as much as bhp! I fitted the lowest front splitter I can find not only cos it looks drokking cool but it should also give me some aero aids
Future plans for fuel economy:
Upper grill block.
Manual supercharger bypass for a few percent increase at motorway speeds - the bypass can close at partial vacuum.
Tidy up underside aero, things such as partial engine floor & splitter.
Install EGT sensor.
Install a water hydrolysss unit, lean out the mixture and advance the timing to experiment with fuel economy.
Switcheable warm air intake.
Future plans for bhp:
Custom inlet manifold with charge cooler.
Either M90 or M112 latest gen supercharger - Gotta love the instant power
Perhaps a dual 2" high flow but quiet exhaust.
The gearbox is also as low as the sump therefore a dry sump won't actually gain me any height, tbh if I could lower the intake then i could raise the engine atleast half an inch!
It does seem unusual to drop in displacement! Here are the main reasons i chose to do the swap:
1. Weight loss.
2. The glorious 6 speed gearbox.
3. Much higher potential power on stock internals.
4. Better fuel economy - i figure in 15 years it would have paid for itself lol.
5. Just to do something different!
It does seem unusual to drop in displacement! Here are the main reasons i chose to do the swap:
1. Weight loss.
2. The glorious 6 speed gearbox.
3. Much higher potential power on stock internals.
4. Better fuel economy - i figure in 15 years it would have paid for itself lol.
5. Just to do something different!
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