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greed...which way to go with an engine upgrade

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2manyspits Avatar
2manyspits Thomas Schlundt
south bend, IN, USA   USA
we have been autocrossing a spitfire for years. very seldom does the car get beat. I would never run a 1500 they have to much of a tendency to put number three through the side of the block. 1300 small crank balanced good for 7000 on autocross course. Don't forget the car is competitive in FSP.

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clshore Carter Shore
Beverly Hills, FL, USA   USA
Hmm,
Honda has made the 1.5L VTEC Turbo L15 the base motor on all 2018 Accords.
Stock, it makes 192 HP, and 192 ft-lb of torque from 1500-5000 RPM.
Honda reliability, 50K+ miles
Weighs LESS than a Spitfire 1500.

Or, the 'plain jane' L15A7 is normally aspirated, 'only' makes about 120 HP, can be had for about $500 nowdays.

Of course, you would need to adapt a RWD transmission.

Some candidates:
Spitfire/GT6 4 speed, perhaps w O/D
TR-6 4 speed, perhaps w O/D
Suzuki Samurai 5 speed
Ford T-9 5 speed.
Toyota T-50 5 speed
Toyota W58 5 speed
Miata 5 speed (various versions over the years from NA - NC)
BMW 5 speed
Honda S2000 6 speed



Edited 1 time(s). Last edit at 2018-03-01 01:27 PM by clshore.

79bluespit Avatar
79bluespit Rick Lazio
Burlington, ON, Canada   CAN
Don't be scared of the 1500. Sometimes I wonder if the 1500 really is more prone to rod/crank failure than the 1300 BC twice as many 1500' were built. Logically you will see more 1500 with this problem. One thing to consider is the factory compensated for this by widening crank throws providing more crank support.

My suggestions for hard use are the mgb clevitte 77 rod bearing - have to machine crank to accept. Firdanza flywheel and custom make aluminum pulley. Shot peen rods cosworth or ARP bolts. Full circle punned thrust washers.

After that the recipe for more power is no secret. Proper camshaft, higher compression, better carburetion, exhaust manifold. Tailored to suit your rpm range.

One thing I'm working on this month is the Toledo 1300 single manifold to fit with the euro exhaust manifold. By eyeballing it it looks to fit by grinding away the coolant passage. If it works it will be a torque monster esp with HS6 carb good to 5000 rpm. To my knowledge no triumph 1300/1500 has been run with this set up as without grinding the two manifolds don't fit. Shud offer less weight, more torque and ease of tuning, better fuel consumption over twins. But this only works with Toledo 1300 rounded runner manifold.... Not the log inlet manifold.



Edited 1 time(s). Last edit at 2018-04-14 09:41 PM by 79bluespit.

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79bluespit Avatar
79bluespit Rick Lazio
Burlington, ON, Canada   CAN
One more thing you can do... Use a midget 1500 trans. First 3 gears are a bit revier than spit ratios. 4th is identical.

arturo64 Avatar
arturo64 Arthur T
Billings, MT, USA   USA
interesting plan with the single carb. there are some things that I just won't be able to change just cause I like em, and that's my twin SU's. put em on my gt6 too, just cause I love the things. I'm now planning to stick with my 1300 small journal for the season or two it will survive. might just rebuild and keep going too. but I heard a weird build idea of using a large journal 1300 and offset grinding the cranking to accept small journal rods. so it would bump it to a 1400 and lessen the weight of the crank. then shave some more glut off crank to let it spin up and walla! more CC without to much more spinning weight. sounds like a fun idea. now for Actual research rather than it being some comic book idea.

interesting idea on the midget trans. I'm actually having a full synchro 3 rail mailed to me right now, just so I can down shift into 1st and keep my revs up. I looked quick for the ratios for the Midget trans you mentioned but didn't find them yet, weird they'd be different but i'll look into it.



Arthur
68 spit
70 gt6+

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1526150 by 79bluespit Don't be scared of the 1500. Sometimes I wonder if the 1500 really is more prone to rod/crank failure than the 1300 BC twice as many 1500' were built. Logically you will see more 1500 with this problem. One thing to consider is the factory compensated for this by widening crank throws providing more crank support.

My suggestions for hard use are the mgb clevitte 77 rod bearing - have to machine crank to accept. Firdanza flywheel and custom make aluminum pulley. Shot peen rods cosworth or ARP bolts. Full circle punned thrust washers.

After that the recipe for more power is no secret. Proper camshaft, higher compression, better carburetion, exhaust manifold. Tailored to suit your rpm range.

One thing I'm working on this month is the Toledo 1300 single manifold to fit with the euro exhaust manifold. By eyeballing it it looks to fit by grinding away the coolant passage. If it works it will be a torque monster esp with HS6 carb good to 5000 rpm. To my knowledge no triumph 1300/1500 has been run with this set up as without grinding the two manifolds don't fit. Shud offer less weight, more torque and ease of tuning, better fuel consumption over twins. But this only works with Toledo 1300 rounded runner manifold.... Not the log inlet manifold.

79bluespit Avatar
79bluespit Rick Lazio
Burlington, ON, Canada   CAN
Ya I like that 1400 idea. A lot. I willl file that one away in ny brain. Based on the race video I saw... Ur better off with twins anyway. U need a revvy engine with track racing like that. With parking lot slaloms I think the single upgrade would work better.

Don't know why mg used lower gears , but they did. Except for 4th. And only on the 1500 midget.

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