Performance difference between XE & LET

[Nova_Tek]

I'm trying to weigh up the cost of conversion with the performance of the XE and LET engines.

What are the typical 0-60 times of a standard XE & LET and the top speed.

Ok it can vary depending on the weight of the car and other variable but just need to get an idea.

Then I'll see which is worth doing.

:thumb:

[Jay]

0-60 of a mates old standard xe'd nova was 6.67, A LET will obviously be quicker as its 50 brake more! His top speed was 138mph with an f16 box and with f20 was 148mph.

Jay

[Nova_Tek]

Thanks Jay,

So with a LET we are talking about 6's top speed of around 155 I'm assuming with the correct gearbox

I'd like to hear some figures from any LET owners that know their 0-60 and top speed.

[Jay]

Well it all depends what box u go for, F20 or F28. i have known Let Novas to go 160mph + !

Jay

[krobinson]

A few 280-300bhp LET's ran over 160mph at brunters (f28 box's)

[Nova_Tek]

What would be the best box to go for thats the question really.

Unless theres someone on here that uses and F20 box with a LET and someone else who has a F28 and for both of these people to post on my thread :D

[Nova_Tek]

So my guess of 155mph on a standard LET with an F28 isnt too far off the mark.

[krobinson]

If your running an XE, use the F20, and LET, use the F28.

Most people blow up their F20's with the torque from a LET, especially on phase chips.

Keith

[Jay]

A few 280-300bhp LET's ran over 160mph at brunters (f28 box's)

Oh!

[Nova_Tek]

Any LET owners?

[Jim Mcrae]

Is there any benefit with the F16 on the XE, as thats what is fitted to mine, just curious really beacuse it's unussual.

[Philsutton]

A well set up let will get into the 4's 0-60 wise, quite a few people have done so far.

Top speed they have the ability to hit the 180mph's but most will do 160 ish. I would like to say what I got in mine but it started weavnig all over the shop while almost at the limiter in 6th and thus didnt get a reading.

[chimp007_uk]

I would like to say what I got in mine but it started weavnig all over the shop while almost at the limiter in 6th and thus didnt get a reading.

HAHA lol

My XE with F20 hit 145 on the clocks which was 136 on the gps. Its more for acceleration, and i'll never be doing that sort of speed in it again.

[Nova_Tek]

A well set up let will get into the 4's 0-60 wise, quite a few people have done so far.

In standard form or modified engine?

I wouldnt really be to bothered if I couldnt hit 180mph unless I had access to my own airstip. 160 is more then adequte and even then how often if ever, would you get top that speed?

I've seen LET Nova's in TV mag get to low 4's but they have been modified. So it looks like 5.5s - 6s is what to expect.

Now its a case of seeing if an extra .5sec - 1 sec off the 0-60 and extra 10 - 15mph is worth the extra bills

But the LET is so tempting. Off to program my calculator for XE & LET formulae lol

[R1CH]

XE's are quick and will be fun car to drive (if done well), but an LET isn't in the same league, there way more fun to drive, if you can afford to build an LET (properly - decent brakes, suspension, F28 ect..) then do it, can easily get them to see 280bhp (although most 2nd hand engines will be tired / high milage so dont expect them to last for ever) for not a lot of £££, they'll see off most things on the road as well (in a straight line !).

[Nova_Tek]

I will be looking to do it properly as I have waited many years and fantasied many times about a big engine in my Nova :D

If I go for the LET it will be in standard form maybe with minor mods like the XE cam's set up properly and the usual stuff like panel filter and quality exhaust system, so Im not after mad power but do want something that will shut certain flash drivers up and for me to now that if needed the performance is there.

Brakes I am sorting right now, fully refurbing the Ate calipers quality set of pads and probably GM disks, already have things like strutbrace etc ready.

So its just a case of parting with the cash and finding a good engine. If I was loaded then Id pop off to Vaux and get one of their fully recon'd LETs with 80k warrenty for £1400 :cry:

[craig green]

In my experience the figures dont point to much, a turbo motor is far torquier when on boost. You can climb hills far quicker without screaming its nutts off. Overtaking is far easier & safer (time exposed to danger).

You will also notice that when blasting round lanes & twisty roads a turbo car will reach the next bend considerably quicker than a N/A car & thus give your brakes a much harder time.

Turbo's do need more care & servicing attention than N/A which can pretty much be abused with no ill effects. High revving N/A is better suited to track work though so that might be a consideration.


Is there any benefit with the F16 on the XE, as thats what is fitted to mine, just curious really beacuse it's unussual.

F16CR is a little lower geared (FD) so typically should accelerate a tad quicker & top out a tad slower than the F20. The F20 was designed for the XE & a slightly bigger clutch & meant to be a bit more robust to withstand XE abuse. GM build in quite a safety margin for power with their transmissions so an F16 isnt really stretched in an XE tbh.

[Nova_Tek]

In my experience the figures dont point to much, a turbo motor is far torquier when on boost. You can climb hills far quicker without screaming its nutts off. Overtaking is far easier & safer (time exposed to danger).

You will also notice that when blasting round lanes & twisty roads a turbo car will reach the next bend considerably quicker than a N/A car & thus give your brakes a much harder time.

Turbo's do need more care & servicing attention than N/A which can pretty much be abused with no ill effects. High revving N/A is better suited to track work though so that might be a consideration.

You've just touched on something I didnt consider... climibing large inclines. Where the car would be used in the near future has some steep hills, on some cars I've had to climb them in first gear :eek: , also has twisty roads and very nice straights aswell. So its, %98 of the time, gonna be a road car.

I appreciate that turbo's are slightly more higher maintainence but the LET was not an out and out race engine, its still a road car engine so it had more normal service intervals, of course a few more engine parts may need a bit of attention compared to a N/A engine and the engines now being older the need for servicing is important but I know that and any appreciator of cars and engines will give git plenty of TLC.

Just need an extra grand now:cry:

[The Simps]

Having owned both for several years I'd definately go LET on a road car.

0-60 isn't that much difference in standard form compared to an XE but beyond that the extra torque makes a hell of a difference!

You can drive them normally thru low revs and high gears because of the torque and I'd regularly get 40+ mpg. But when you belt it it really puts a smile on your face.

If you fit an XE I guarrantee you'll want to upgrade to a LET within 6mths to a year, so why waste the money - do it right the 1st time!

[Andy]

My mate used to have an XE with an F28 on,it was frantic up to 100 then took a while to flat out

[garethcolley]

I have a LET running 290, chipped, uprated injectors, fuel pressure, pump and cooler with XE inlet cam, vernier pulleys, new hydraulic lifters, front mount and alloy pipework. Cost 1500 with a mint F20 and all conversion parts! My mate has an XE, spent 1500 quid on the engine from V-Tuning a year ago!!! then a further £600 minimum on bits and bobs. I would defo go for the LET conversion even if its standard. Ive recently been in his and like the previous comment it just isnt in the same league.

Going back to F20's blowing up. If you shift down at stupid revs and are constantly on the limiter then yeh it will go but as would most. Doubt ill bother gettin an F28. You would be going some to be doing that in a LET anyway cos you would end up in a wall. It really does scare me flooring mine from 2nd through to 4th. The boost although progressive is just ridiculous.

[Nova_Tek]

Cheers for the comments people, a lot of valuable points, like Simps said, if I end up loving the XE I'd always be thinking about "should've got the LET", Its always the case :). Plus getting it to be abit more powerful will probably end up costing most of the difference in the engine costs anyway. I like the notion of 40mpg on sensible driving, thats close to what I get in my 1.2.

I think I'll end up going with the F28 as opposed to the F20 but worst case scenario if I cant source a good F28 then F20 is good enough to use.

Like I said before apart from minor mods like the XE cam, filter and exhaust it will be pretty much standard, mainly due to money and secondly it will be more relaible in the long run too.

Need to start making a list of bits 'n' pieces and give myself a budget to stick to tightly.

I have been reading the How To's section regarding conversions. Am I right in thinking that the LET is very similar to an XE transplant, same mount issues, gearbox issues and odd bits mentioned in the thread?

I am not running any front ARB and from relevant threads theres not much need for one, a good suspension setup and a strut brace will be installed, therefore do I need to do the tie-bar lowering mod or keep it as is?

Cheers lads your posts are most useful :thumb:

[The Simps]

Going back to F20's blowing up. If you shift down at stupid revs and are constantly on the limiter then yeh it will go but as would most. Doubt ill bother gettin an F28.

You will regret it mate! F28 comes into its own on dual carrieageway/motorway.

My old one was running around 280bhp/340lbft and I came up behind a Cerberra in 6th at 80mph. He put his foot fown (probably in top gear like me) and there was nothing between us up to 145mph when he backed off to look over and go "what the fnck!".

Spend £50 on p2 copies and you're laughin,

[The Simps]

Like I said before apart from minor mods like the XE cam, filter and exhaust it will be pretty much standard, mainly due to money and secondly it will be more relaible in the long run too.

Need to start making a list of bits 'n' pieces and give myself a budget to stick to tightly.



Fitting a LET is very similar to LET. The only difference is turbo to rad clearance, which intercooler you go for and whehter you go F28 or not.

PM me if your serious mate and I can walk you thru it :thumb:

[garethcolley]

p2 Copies?

[Nova_Tek]

You will regret it mate! F28 comes into its own on dual carrieageway/motorway

Fitting a LET is very similar to LET. The only difference is turbo to rad clearance, which intercooler you go for and whehter you go F28 or not.

PM me if your serious mate and I can walk you thru it :thumb:

Thought the LET would be the same as a LET :p

I will be using a charge-cooler as I have the snowplough bumper and theres no room for a FMIC. Rad wise been reading some people running standard stuff but I my go from a 1.2 to a GTE one instead. I also wanna use the F28. Is this the same as fitting a F20 i.e gearbox spacer needed or is it a bit more involved then that?

I am serious and do wanna do it, if things go to plan, then hopefully withing 2 months, otherwise Id wanna do it by end of august ideally.

Just have a few things to sort out, may be moving abroad so theres alot on my plate. Soon as I reduce my work load.

Thanks :thumb:

[Adam]

No, the mount needs cutting off the car and a new one welding on to fit the F28.
And theres a few jobs do on the box, converting it to 2wd etc etc.

Ph2 copies= Phase 2 chips.
Increased OB pressure, and Held Boost pressure to take power to around 270-280bhp.

[Nova_Tek]

Really? Hmm wasnt expecting that. Welding is not something I can do at home and it would have to be given to someone to do. Is there not an actual mount available to adapt the box?

How difficult is it to convert the F28 to 2WD?

[Adam]

Yeah theres a mount available to fit it, but the shell mount still needs cutting off the shell, and a new custom one fitting.

Pretty easy to convert to fwd iirc

[Nova_Tek]

Now its a matter of finding someone that can do that particular job.

Fitting the engine wiring etc Im reletively confident about, although being my first time from what I have read its straight forward, obvisouly there maybe the odd minor obsticle.

I, in this case, may have to consider the F20.

[Nova_Tek]

Ahh ok just looking at the chris astley site

http://www.chrisastleymotorsport.com/product_info.php?cPath=22&products_id=28&osCsid=7068ef35c7cf6e4d31147b7c5ecaa1de

so Its just a case of welding this prefab mount. Ok not so involving as making your own mount.

Still need to find someone though.

[Adam]

Yeah, that part needs welding to the chassis leg, and it then just bolts up.

Will this be your first engine conversion?

A let is not a job for a first timer IMO

Check out Simps Red Nova Turbo project thread on mig, it has a lot of detail about fitting/wiring a Let, and pics of fitting the gearbox mount etc etc.

[Nova_Tek]

Yeh it will be my first. Reason why I considered to do this was to keep the costs down & maybe it would prove to be a huge learning curve for my to get to grips with this sorta work and generally get to know the car better, theres no better way of learning the doing it yourself, but I understand that its not easy. Finding someone reliable to do it without moaning is a mission aswell.

Will check out his thread on Mig again think I read it a while ago but wil have to refresh my memory.

[The Simps]

Taken from my latest project thread:- http://www.pngclub.com/forum/showthread.php?t=89638

http://img.photobucket.com/albums/v310/TheSimps/Nova/Nova%20Coupe%20Project/28-12-071.jpg
http://img.photobucket.com/albums/v310/TheSimps/Nova/Nova%20Coupe%20Project/28-12-075.jpg
http://img.photobucket.com/albums/v310/TheSimps/Nova/Nova%20Coupe%20Project/28-12-076.jpg
http://img.photobucket.com/albums/v310/TheSimps/Nova/Nova%20Coupe%20Project/28-12-078.jpg


Its worth the extra effort involved mate.

As far as welding goes I hired one for £15 for the day from my local tool shop for my red turbo. If you're not confident doing that just look in yellow pages for a welder who does onsite welding. You've only got to get it grinded off and lined up and he zaps in a few beads of weld. 10mins job for him tops.

[Nova_Tek]

Is that the passenger side mount?

Is it that and the geabox mount that needs to be altered to fit the bigger blocks?

I know that 1 mount is fine but 2 of them needs to be altered.

[The Simps]

thats right. here's the link for the rear mount how to:- http://www.pngclub.com/forum/showthread.php?t=90103

[Nova_Tek]

Thanks for that.

All there Chris Astley mounts that are in the conversion kit, do they just bolt on to the existing mounts or is it a case of these mounts are fabricated to be welded on?

Cheers for you vast knowledge Simps :thumb:

[The Simps]

the mounts are all bolt on except the f28 one.

you can see in my 2nd pic how the front block mount uses the standard mount position.

You also need to be aware that if you go f28 you will need to modify your gear linkage and change your tie bar arrangement to make it lower. lol

[Nova_Tek]

Wont the tie bar kit from christ astley do the trick?

[The Simps]

which one you mean?

[The Simps]

if you mean these ones then no.

http://www.chrisastleymotorsport.com/images/ARBLOWER.jpg

[The Simps]

You need to run the tie bar on the bottom of the control arm to clear the box. the easiest way to do this is run the ball joint on top, use a lowering block and bolttie bar on bottom like this on Rich Ms nova:-

http://img.photobucket.com/albums/v310/TheSimps/DSC00543.jpg


You also ideally want to plate the bottom arms for strength. You then need to lower where the tie bar meets the front crossmember. Chris used to sell a kit to do this with uprated bearing. I've elongated my top bolt hole and will run a spacer block up to 25mm.

http://img.photobucket.com/albums/v310/TheSimps/Nova/Nova%20Coupe%20Project/02-03-2008.jpg
http://img.photobucket.com/albums/v310/TheSimps/Nova/Nova%20Coupe%20Project/21-03-082.jpg

[Nova_Tek]

Thats a lotta work. If time is tight then I may stick a F20 instead as that needs less work.

F28 will be sweet but will depend how much time I will have to do it.

[craig green]

Whats the rush. Do it properly. Do it once.

[Philsutton]

Thats a lotta work. If time is tight then I may stick a F20 instead as that needs less work.

F28 will be sweet but will depend how much time I will have to do it.

Do you have the time to be changing boxes all the time? Do it right first time it will work out in the long run.

[The Simps]

I've just put the full guide in Technical archive:- http://www.pngclub.com/forum/showthread.php?t=98463

There all little jobs tbh that can be done before you fit the engine.

[Nova_Tek]

Whats the rush.

Where do I start mate, I am pushed for time in many matters and the less time this conversion takes the better.

I fully understand that the F28 is the ultimate mate to the LET but like I said if it gets to the point when Im pushing for time then I may have to do a slight downgrade to an F20. I could really take the p*ss and stick in a F16 which I have in my garage as a spare for my dads SRi but thats stupid and I know eventually, or sooner, it will die lol

Seeing as people have run F20's on LET's and even moddified ones and have worked then its a feasible alternative to stick one on a standard LET.

Like I said its only if time runs out.

[The Simps]

i ran my an f16 for 8mths on eds phase 2 and it survived. depends how you drive. i drive like a girl.

[Nova_Tek]

I drive hard when appropriate or when theres a right n*b that needs to be shown a lesson :) most of the time Im sensible :D

Is there any difference with 0 - 60 between the boxes?

[The Simps]

never tried 0-60 runs - thats when things break! I only really went after things that were rolling at around 80mph+

[Nova_Tek]

never tried 0-60 runs - thats when things break! I only really went after things that were rolling at around 80mph+

I can imagine on a F16 :)

[Nova_Tek]

Whats the difference between F28 and the F25 mounting wise and gears?

what car were they on? and can they be fitted to a LET?

Thanks muchly.

[The Simps]

f25 came on the v6s. Most people change them for the f20 or f28 - its a crap box with reeeeeaaaaaaalllllllllyyyyyyy long gears.

[Nova_Tek]

Righty, good for top speed but none to clever for quickness Id imagine

[dan16v]

Either way you will need welding done! if i was doing it id get the bay stitch welded and get the engine bay strengthining plates welded in! for xe or let!!

[Nova_Tek]

Yeh will be doing that mate. Either the plates or welding done with strut top plates welded on aswell.

[The Simps]

so if the welders already going to be out you might aswell go f28...